Backport implementation of bug 259768: "Use optimal jobs number:

highly misleading" from 8.1 to 8.0.

Change-Id: I5a3d33b21b306b30411dc6eb2325d77d0383c9bf
Reviewed-on: https://git.eclipse.org/r/9731
Reviewed-by: Doug Schaefer <dschaefer@qnx.com>
IP-Clean: Doug Schaefer <dschaefer@qnx.com>
Tested-by: Doug Schaefer <dschaefer@qnx.com>

build/org.eclipse.cdt.managedbuilder.core/schema/buildDefinitions.exsd

@@ -1757,8 +1757,27 @@ If this attribute is not specified, MBS will assume that there are no reserved m
          <attribute name="parallelBuildCmd" type="string">
             <annotation>
                <documentation>
-                  specifies the &quot;parallel build&quot; builder option. 
+                  Specifies the command for &quot;parallel build&quot;.
-If the builder supports specifying custom number of parallel jobs, the option definition may contain &quot;*&quot; the Build System sill substitute the &quot;*&quot; with the number of parallel threads to be used.
+If the builder supports specifying custom number of parallel jobs the option definition may contain &quot;*&quot;. The Build System will substitute the &quot;*&quot; with the number of parallel threads to be used. In case of &quot;unlimited&quot; jobs jobs number will be omitted.
+For example, builder representing GNU make would define parallelBuildCmd as &quot;-j*&quot;.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="parallelBuildOn" type="boolean">
+            <annotation>
+               <documentation>
+                  Defines if the parallel build is enabled in newly created project by default (when parallel build is supported). The number of jobs is defined by &quot;parallelizationNumber&quot; attribute. If &quot;parallelizationNumber&quot; is not defined &quot;optimal&quot; value will be used.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="parallelizationNumber" type="string">
+            <annotation>
+               <documentation>
+                  Sets maximum number of parallel threads/jobs to be used by builder (that value can be changed after creation of project by user).
+A positive number or value &quot;optimal&quot; or &quot;unlimited&quot; are recognized:
+- number 1 will cause parallel build to be turned off,
+- &quot;optimal&quot; will set maximum number of jobs to number of processors on the system,
+- &quot;unlimited&quot; will make builder to run as many threads/jobs as possible.
                </documentation>
             </annotation>
          </attribute>

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/IBuilder.java

@@ -76,13 +76,16 @@ public interface IBuilder extends IHoldsOptions, IMakeBuilderInfo {
 	static final String ATTRIBUTE_CUSTOMIZED_ERROR_PARSERS = "customizedErrorParsers"; //$NON-NLS-1$
 	static final String ATTRIBUTE_CUSTOM_PROPS = "customBuilderProperties"; //$NON-NLS-1$
 
-//	static final String ATTRIBUTE_CUSTOMIZED_ERROR_PARSERS = "customizedErrorParsers"; //$NON-NLS-1$
-
 	static final String ATTRIBUTE_IGNORE_ERR_CMD = "ignoreErrCmd"; //$NON-NLS-1$
 	static final String ATTRIBUTE_STOP_ON_ERR = "stopOnErr"; //$NON-NLS-1$
+	
 	static final String ATTRIBUTE_PARALLEL_BUILD_CMD = "parallelBuildCmd"; //$NON-NLS-1$
-	static final String ATTRIBUTE_PARALLELIZATION_NUMBER = "parallelizationNumber"; //$NON-NLS-1$
 	static final String ATTRIBUTE_PARALLEL_BUILD_ON = "parallelBuildOn"; //$NON-NLS-1$
+	static final String ATTRIBUTE_PARALLELIZATION_NUMBER = "parallelizationNumber"; //$NON-NLS-1$
+	/** @since 8.0 */
+	static final String VALUE_OPTIMAL = "optimal"; //$NON-NLS-1$
+	/** @since 8.0 */
+	static final String VALUE_UNLIMITED = "unlimited"; //$NON-NLS-1$
 	static final String PARALLEL_PATTERN_NUM = "*"; //$NON-NLS-1$
 	static final String PARALLEL_PATTERN_NUM_START = "["; //$NON-NLS-1$
 	static final String PARALLEL_PATTERN_NUM_END = "]"; //$NON-NLS-1$
@@ -92,15 +95,9 @@ public interface IBuilder extends IHoldsOptions, IMakeBuilderInfo {
 	static final String DEFAULT_TARGET_INCREMENTAL = "all";  //$NON-NLS-1$
 	static final String DEFAULT_TARGET_CLEAN = "clean";  //$NON-NLS-1$
 	static final String DEFAULT_TARGET_AUTO = "all"; //$NON-NLS-1$
-	
+	/** @since 6.0 */
-	/**
-	 * @since 6.0
-	 */
 	static final String ATTRIBUTE_COMMAND_LAUNCHER = "commandLauncher"; //$NON-NLS-1$
-
+	/** @since 8.0 */
-	/**
-	 * @since 8.0
-	 */
 	static final String ATTRIBUTE_BUILD_RUNNER = "buildRunner"; //$NON-NLS-1$
 	
 	/**

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/IMultiConfiguration.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2010 Intel Corporation and others.
+ * Copyright (c) 2007, 2011 Intel Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -13,19 +13,56 @@ package org.eclipse.cdt.managedbuilder.core;
 import org.eclipse.cdt.core.settings.model.ICMultiItemsHolder;
 import org.eclipse.cdt.managedbuilder.buildproperties.IBuildProperty;
 import org.eclipse.cdt.managedbuilder.buildproperties.IBuildPropertyValue;
+import org.eclipse.cdt.managedbuilder.internal.core.Builder;
 
 /**
+ * This class is to combine multiple configurations to one to support
+ * selection of multiple configurations on property pages.
+ * 
  * @noextend This class is not intended to be subclassed by clients.
  * @noimplement This interface is not intended to be implemented by clients.
  */
 public interface IMultiConfiguration extends IConfiguration, ICMultiItemsHolder {
 	
+	/**
+	 * Check if all configurations' builders are operating in parallel mode.
+	 * @return {@code true} if parallel mode is enabled for all configurations,
+	 *    {@code false} otherwise.
+	 */
 	boolean getParallelDef();
-	void    setParallelDef(boolean def);
+	/**
+	 * Set same parallel execution mode for all configurations' builders.
+	 * @see Builder#setParallelBuildOn(boolean)
+	 * 
+	 * @param parallel - the flag to enable or disable parallel mode.
+	 */
+	void setParallelDef(boolean parallel);
 
+	/**
+	 * Returns maximum number of parallel threads/jobs used by the configurations' builders.
+	 * @see #setParallelDef(boolean)
+	 * 
+	 * @return - maximum number of parallel threads or jobs used by each builder or 0 if the numbers
+	 *    don't match. 
+	 */
 	int getParallelNumber();
-	void    setParallelNumber(int num);
 
+	/**
+	 * Sets maximum number of parallel threads/jobs to be used by each builder.
+	 * 
+	 * @param jobs - maximum number of jobs or threads, see for more details
+	 *    {@link Builder#getOptimalParallelJobNum()}.
+	 */
+	void setParallelNumber(int jobs);
+	
+	/**
+	 * Check if all configurations' internal builders are operating in parallel mode.
+	 * @return {@code true} if parallel mode is enabled for all configurations,
+	 *    {@code false} otherwise.
+	 * 
+	 * @deprecated since CDT 9.0. Use {@link #getParallelDef()}
+	 */
+	@Deprecated
 	boolean getInternalBuilderParallel();
 
 	boolean isInternalBuilderEnabled();

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/InternalBuildRunner.java

@@ -65,7 +65,7 @@ public class InternalBuildRunner extends AbstractBuildRunner {
 	public boolean invokeBuild(int kind, IProject project, IConfiguration configuration,
 			IBuilder builder, IConsole console, IMarkerGenerator markerGenerator,
 			IncrementalProjectBuilder projectBuilder, IProgressMonitor monitor) throws CoreException {
-		boolean isParallel = builder.isParallelBuildOn() && builder.getParallelizationNum() > 1;
+		boolean isParallel = builder.getParallelizationNum() > 1;
 //		boolean buildIncrementaly = true;
 		boolean resumeOnErr = !builder.isStopOnError();
 
@@ -173,8 +173,7 @@ public class InternalBuildRunner extends AbstractBuildRunner {
 					break;
 				case IBuildModelBuilder.STATUS_ERROR_LAUNCH:
 				default:
-					buf.append(ManagedMakeMessages
+					buf.append(ManagedMakeMessages.getResourceString(BUILD_FAILED_ERR));
-							.getResourceString(BUILD_FAILED_ERR));
 					break;
 				}
 				buf.append(System.getProperty("line.separator", "\n")); //$NON-NLS-1$//$NON-NLS-2$
@@ -194,8 +193,7 @@ public class InternalBuildRunner extends AbstractBuildRunner {
 				epmOutputStream.close();
 				epmOutputStream = null;
 				// Generate any error markers that the build has discovered
-				monitor.subTask(ManagedMakeMessages
+				monitor.subTask(ManagedMakeMessages.getResourceString(MARKERS));
-						.getResourceString(MARKERS));
 
 				bsMngr.setProjectBuildState(project, pBS);
 			} else {

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildProcessManager.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006, 2007 Intel Corporation and others.
+ * Copyright (c) 2006, 2011 Intel Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -11,42 +11,28 @@
 
 package org.eclipse.cdt.managedbuilder.internal.buildmodel;
 
-import java.io.BufferedReader;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.Vector;
 
 import org.eclipse.cdt.managedbuilder.buildmodel.IBuildCommand;
-import org.eclipse.cdt.managedbuilder.core.ManagedBuildManager;
-import org.eclipse.cdt.managedbuilder.envvar.IBuildEnvironmentVariable;
-import org.eclipse.cdt.managedbuilder.envvar.IEnvironmentVariableProvider;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
 
 /**
  * This class implements process pool management for internal builder 
- *
- * NOTE: This class is subject to change and discuss, 
- * and is currently available in experimental mode only
  */
 public class BuildProcessManager {
 	protected OutputStream out;
 	protected OutputStream err;
 	protected boolean show;
-	protected ProcessLauncher[] processes;
+	protected Vector<ProcessLauncher> processes;
 	protected int maxProcesses;
 	
-//	 Number of CPUs is not dependent of object instance.
-//   But user can change UI settings for processes number.
-//   So we cannot set procNumber directly to maxProcesses. 	
-	static int procNumber = 0;
-	
 	/**
 	 * Initializes process manager
 	 * 
@@ -59,7 +45,7 @@ public class BuildProcessManager {
 		err = _err;
 		show = _show;
 		maxProcesses = _procNumber;
-		processes = new ProcessLauncher[maxProcesses];
+		processes = new Vector<ProcessLauncher>(Math.min(10, maxProcesses), 10);
 	}
 	
 	/**
@@ -79,18 +65,19 @@ public class BuildProcessManager {
 	 * @param monitor Progress monitor for this task 
 	 */
 	public ProcessLauncher launchProcess(IBuildCommand cmd, IPath cwd, IProgressMonitor monitor) {
-		if (hasEmpty()) {
+		for (int i = 0; i < maxProcesses; i++) {
-			int i = 0;
+			if (i >= processes.size()) {
-			for (; i < maxProcesses; i++) {
+				ProcessLauncher process = new ProcessLauncher(cmd.getCommand(), cmd.getArgs(), mapToStringArray(cmd.getEnvironment()), cwd, out, err, monitor, show);
-				if (processes[i] == null || processes[i].queryState() == ProcessLauncher.STATE_DONE) {
+				processes.add(process);
-					break;
+				process.launch();
-				}
+				return process;
-			}
 				
-			if (i < maxProcesses) {
+			}
-				processes[i] = new ProcessLauncher(cmd.getCommand(), cmd.getArgs(), mapToStringArray(cmd.getEnvironment()), cwd, out, err, monitor, show);
+			if (processes.get(i).queryState() == ProcessLauncher.STATE_DONE) {
-				processes[i].launch();
+				ProcessLauncher process = new ProcessLauncher(cmd.getCommand(), cmd.getArgs(), mapToStringArray(cmd.getEnvironment()), cwd, out, err, monitor, show);
-				return processes[i];
+				processes.set(i, process);
+				process.launch();
+				return process;
 			}
 		}
 		return null;
@@ -102,36 +89,37 @@ public class BuildProcessManager {
 	 * returned as a result. Otherwise this method returns null.
 	 */
 	public ProcessLauncher queryStates() {
-		ProcessLauncher result = null;
+		for (ProcessLauncher process : processes) {
-		
+			int state = process.queryState();
-		for (int i = 0; i < maxProcesses; i++) {
+			if (state != ProcessLauncher.STATE_RUNNING && state != ProcessLauncher.STATE_DONE)
-			if (processes[i] != null) {
+				return process;
-				int state = processes[i].queryState();
-				if (state != ProcessLauncher.STATE_RUNNING) {
-					if (state != ProcessLauncher.STATE_DONE && result == null)
-						result = processes[i];
-				}
-			}
 		}
 		
-		return result;
+		return null;
 	}
 
 	/**
 	 * Checks states of all currently running processes. 
 	 */
 	public boolean hasEmpty() {
-		for (int i = 0; i < maxProcesses; i++) {
+		if (processes.size() < maxProcesses)
-			if (processes[i] == null) 
 			return true;
-			else {
+		
-				if (processes[i].queryState() != ProcessLauncher.STATE_RUNNING) 
+		for (ProcessLauncher process : processes) {
+			if (process.queryState() != ProcessLauncher.STATE_RUNNING) 
 				return true;
 		}
-		}
 		return false;
 	}
 
+	/**
+	 * Returns maximum threads used up to that point
+	 */
+	public int getThreadsUsed() {
+		return processes.size();
+	}
+	
+
 	
 	/**
 	 * Converts map to strings array
@@ -152,40 +140,10 @@ public class BuildProcessManager {
 	
 	/**
 	 * @return Number of processors detected
+	 * @deprecated since CDT 9.0 - just use Runtime.getRuntime().availableProcessors()
 	 */
+	@Deprecated
 	static public int checkCPUNumber() {
-		if (procNumber > 0) return procNumber;
+		return Runtime.getRuntime().availableProcessors();
-		
-		procNumber = 1;
-		int x = 0;
-		String os = System.getProperty("os.name"); //$NON-NLS-1$
-		if (os != null) {
-			if (os.startsWith("Win")) { //$NON-NLS-1$
-				IEnvironmentVariableProvider evp = ManagedBuildManager.getEnvironmentVariableProvider();
-				if (evp != null) {
-					IBuildEnvironmentVariable var = evp.getVariable("NUMBER_OF_PROCESSORS", null, false, false); //$NON-NLS-1$
-					if (var != null) {
-						try {
-							x = new Integer(var.getValue()).intValue();
-							if (x > 0) { procNumber = x; }
-						} catch (NumberFormatException e) {} // fallthrough and return default
-					}
-				}
-			} else { // linux
-				String p = "/proc/cpuinfo"; //$NON-NLS-1$
-				try {
-					BufferedReader r = new BufferedReader(new InputStreamReader(new FileInputStream(p)));
-					String s;
-					while ((s = r.readLine() ) != null ) 
-					   { if (s.startsWith("processor\t:")) x++; } //$NON-NLS-1$
-					r.close();
-					if (x > 0) { procNumber = x; }
-				} 
-				catch (IOException e) {} // fallthrough and return default
-			}
-		}
-		if(DbgUtil.DEBUG)
-			DbgUtil.trace("Number of processors detected: " + procNumber);	//$NON-NLS-1$
-		return procNumber;
 	}
 }

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/ParallelBuilder.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006 Intel Corporation and others.
+ * Copyright (c) 2006, 2011 Intel Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -17,6 +17,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
+import java.util.Vector;
 
 import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.cdt.managedbuilder.buildmodel.IBuildCommand;
@@ -205,18 +206,16 @@ public class ParallelBuilder {
 		if(cwd == null)  cwd = des.getDefaultBuildDirLocation();
 		int threads = 1;
 		if (cfg instanceof Configuration) {
-			if (((Configuration)cfg).getParallelDef())
-				threads = BuildProcessManager.checkCPUNumber();
-			else
 			threads = ((Configuration)cfg).getParallelNumber();
 		}
 		ParallelBuilder builder = new ParallelBuilder(cwd, dirs, out, err, monitor, resumeOnErrors, buildIncrementally);
 		builder.enqueueAll(des);
 		builder.sortQueue();
 		monitor.beginTask("", builder.queue.size()); //$NON-NLS-1$
-		builder.dispatch(new BuildProcessManager(out, err, true, threads));
+		BuildProcessManager buildProcessManager = new BuildProcessManager(out, err, true, threads);
+		builder.dispatch(buildProcessManager);
+		lastThreadsUsed = buildProcessManager.getThreadsUsed();
 		monitor.done();
-		lastThreadsUsed = threads;
 		return IBuildModelBuilder.STATUS_OK;
 	}
 	
@@ -295,10 +294,8 @@ public class ParallelBuilder {
 	 * Dispatches the build queue and returns build status
 	 */
 	protected int dispatch(BuildProcessManager mgr) {
-		ActiveBuildStep[] active = new ActiveBuildStep[mgr.getMaxProcesses()];
+		int maxProcesses = mgr.getMaxProcesses();
-		for (int i = 0; i < active.length; i++) {
+		Vector<ActiveBuildStep> active = new Vector<ActiveBuildStep>(Math.min(maxProcesses, 10), 10);
-			active[i] = null; // new ActiveBuildStep();
-		}
 		
 		int activeCount = 0;
 		int maxLevel = 0;
@@ -332,9 +329,8 @@ public class ParallelBuilder {
 				proceed = false;
 			} else {
 				// Check "active steps" list for completed ones
-				for (int i = 0; i < active.length; i++) {
+				for (ActiveBuildStep buildStep : active) {
-					if (active[i] == null) continue;
+					ProcessLauncher pl = buildStep.getLauncher();
-					ProcessLauncher pl = active[i].getLauncher();
 					if (pl == null) continue; 
 					if (pl.queryState() == ProcessLauncher.STATE_DONE) {
 						// If process has terminated with error, break loop
@@ -345,8 +341,8 @@ public class ParallelBuilder {
 							break main_loop;
 						}
 						// Try to launch next command for the current active step
-						if (active[i].isDone()) continue;
+						if (buildStep.isDone()) continue;
-						if (active[i].launchNextCmd(mgr)) {
+						if (buildStep.launchNextCmd(mgr)) {
 							// Command has been launched. Check if process pool is not maximized yet
 							if (!mgr.hasEmpty()) {
 								proceed = false;
@@ -354,7 +350,7 @@ public class ParallelBuilder {
 							}
 						} else {
 							// Command has not been launched: step complete
-							refreshOutputs(active[i].getStep());
+							refreshOutputs(buildStep.getStep());
 							activeCount--;
 							monitor.worked(1);
 						}
@@ -373,7 +369,7 @@ public class ParallelBuilder {
 			}
 			
 			// Check if we need to schedule another process
-			if (queue.size() != 0 && activeCount < active.length) {
+			if (queue.size() != 0 && activeCount < maxProcesses) {
 				// Need to schedule another process 
 				Iterator<BuildQueueElement> iter = queue.iterator();
 
@@ -381,8 +377,8 @@ public class ParallelBuilder {
 				while (iter.hasNext()) {
 					BuildQueueElement elem = iter.next();
 					
-					// If "active steps" list is full, then break loop
+					// If "active steps" list reaches maximum, then break loop
-					if (activeCount == active.length)
+					if (activeCount == maxProcesses)
 						break;
 					
 					// If current element's level exceeds maximum level of currently built
@@ -391,14 +387,13 @@ public class ParallelBuilder {
 						break;
 
 					//Check if all prerequisites are built
-					IBuildResource[] res = elem.getStep().getInputResources();
 					boolean prereqBuilt = true;
-					for (int j = 0; j < res.length; j++) {
+					for (IBuildResource bldRes : elem.getStep().getInputResources()) {
-						IBuildStep stp = res[j].getProducerStep(); // step which produces input for curr
+						IBuildStep step = bldRes.getProducerStep(); // step which produces input for curr
 						boolean built = true;
-						if (stp != stp.getBuildDescription().getInputStep()) {
+						if (step != step.getBuildDescription().getInputStep()) {
-							for (int k = 0; k < active.length; k++) {
+							for (ActiveBuildStep buildStep : active) {
-								if (active[k] != null && active[k].getStep().equals(stp) && !active[k].isDone()) {
+								if (buildStep != null && buildStep.getStep().equals(step) && !buildStep.isDone()) {
 									built = false;
 									break;
 								}
@@ -417,10 +412,21 @@ public class ParallelBuilder {
 						// Remove element from the build queue and add it to the
 						// "active steps" list.
 						iter.remove();
-						for (int i = 0; i < active.length; i++) {
+						for (int i = 0; i < maxProcesses; i++) {
-							if (active[i] == null || active[i].isDone()) {
+							if (i >= active.size()) {
-								active[i] = new ActiveBuildStep(step);
+								// add new item
-								if (active[i].launchNextCmd(mgr)) activeCount++;
+								ActiveBuildStep buildStep = new ActiveBuildStep(step);
+								active.add(buildStep);
+								if (buildStep.launchNextCmd(mgr))
+									activeCount++;
+								break;
+							}
+							if (active.get(i).isDone()) {
+								// replace old item
+								ActiveBuildStep buildStep = new ActiveBuildStep(step);
+								active.set(i, buildStep);
+								if (buildStep.launchNextCmd(mgr))
+									activeCount++;
 								break;
 							}
 						}

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Builder.java

@@ -40,10 +40,10 @@ import org.eclipse.cdt.core.settings.model.extension.CBuildData;
 import org.eclipse.cdt.core.settings.model.util.CDataUtil;
 import org.eclipse.cdt.core.settings.model.util.LanguageSettingEntriesSerializer;
 import org.eclipse.cdt.internal.core.SafeStringInterner;
+import org.eclipse.cdt.managedbuilder.core.AbstractBuildRunner;
 import org.eclipse.cdt.managedbuilder.core.BuildException;
 import org.eclipse.cdt.managedbuilder.core.ExternalBuildRunner;
 import org.eclipse.cdt.managedbuilder.core.IBuildObject;
-import org.eclipse.cdt.managedbuilder.core.AbstractBuildRunner;
 import org.eclipse.cdt.managedbuilder.core.IBuilder;
 import org.eclipse.cdt.managedbuilder.core.IConfiguration;
 import org.eclipse.cdt.managedbuilder.core.IManagedConfigElement;
@@ -66,6 +66,7 @@ import org.eclipse.cdt.managedbuilder.makegen.IManagedBuilderMakefileGenerator2;
 import org.eclipse.cdt.managedbuilder.makegen.gnu.GnuMakefileGenerator;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IncrementalProjectBuilder;
+import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtension;
@@ -79,7 +80,7 @@ import org.eclipse.core.variables.VariablesPlugin;
 import org.osgi.framework.Version;
 
 public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider<Builder>, IRealBuildObjectAssociation  {
-
+	public static final int UNLIMITED_JOBS = Integer.MAX_VALUE;
 	private static final String EMPTY_STRING = ""; //$NON-NLS-1$
 
 	//  Superclass
@@ -119,10 +120,12 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 	private HashMap<String, String> customBuildProperties;
 //	private Boolean isWorkspaceBuildPath;
 	private String ignoreErrCmd;
-	private String parallelBuildCmd;
 	private Boolean stopOnErr;
-	private Integer parallelNum;
+	// parallelization
-	private Boolean parallelBuildOn;
+	private String parallelBuildCmd;
+	private Boolean isParallelBuildEnabled;
+	private Integer parallelNumberAttribute; // negative number denotes "optimal" value, see getOptimalParallelJobNum()
+
 	private boolean isTest;
 	
 	//  Miscellaneous
@@ -327,9 +330,10 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 		
 		stopOnErr = builder.stopOnErr;
 		ignoreErrCmd = builder.ignoreErrCmd;
+
+		isParallelBuildEnabled = builder.isParallelBuildEnabled;
+		parallelNumberAttribute = builder.parallelNumberAttribute;
 		parallelBuildCmd = builder.parallelBuildCmd;
-		parallelNum = builder.parallelNum;
-		parallelBuildOn = builder.parallelBuildOn;
 
 		if(builder.outputEntries != null){
 			outputEntries = builder.outputEntries.clone();
@@ -372,17 +376,15 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 			} catch (CoreException e) {
 			}
 		}
-		if(getParallelizationNum() != builder.getParallelizationNum()
+		if (isParallelBuildOn() != builder.isParallelBuildOn() && supportsParallelBuild()) {
-				&& supportsParallelBuild()){
 			try {
-				setParallelizationNum(builder.getParallelizationNum());
+				setParallelBuildOn(builder.isParallelBuildOn());
 			} catch (CoreException e) {
 			}
 		}
-		if(isParallelBuildOn() != builder.isParallelBuildOn()
+		if (getParallelizationNumAttribute() != builder.getParallelizationNumAttribute() && supportsParallelBuild()) {
-				&& supportsParallelBuild()){
 			try {
-				setParallelBuildOn(builder.isParallelBuildOn());
+				setParallelizationNum(builder.getParallelizationNumAttribute());
 			} catch (CoreException e) {
 			}
 		}
@@ -556,18 +558,18 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 		if (tmp != null)
 			stopOnErr = Boolean.valueOf(tmp);
 
-        parallelBuildCmd = SafeStringInterner.safeIntern(element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD));
+		tmp = element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD);
-        
-        tmp = element.getAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER);
-        if(tmp != null){
-        	try {
-        		parallelNum = Integer.decode(tmp);
-        	} catch (NumberFormatException e){
-        	}
-        }
-        tmp = element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_ON);
 		if (tmp != null)
-        	parallelBuildOn = Boolean.valueOf(tmp);
+			parallelBuildCmd = SafeStringInterner.safeIntern(tmp);
+
+		tmp = element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_ON);
+		if (tmp != null) {
+			isParallelBuildEnabled = Boolean.valueOf(tmp);
+			if (isParallelBuildEnabled) {
+				tmp = element.getAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER);
+				setParallelizationNumAttribute(decodeParallelizationNumber(element.getAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER)));
+			}
+		}
 
 		// Get the semicolon separated list of IDs of the error parsers
 		errorParserIds = SafeStringInterner.safeIntern(element.getAttribute(IToolChain.ERROR_PARSERS));
@@ -618,6 +620,43 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 			fBuildRunnerElement = ((DefaultManagedConfigElement)element).getConfigurationElement();
 	}
 	
+	private String encodeParallelizationNumber(Integer jobsNumber) {
+		if (jobsNumber <= 0)
+			return VALUE_OPTIMAL;
+		
+		if (jobsNumber.equals(UNLIMITED_JOBS))
+			return VALUE_UNLIMITED;
+		
+		return jobsNumber.toString();
+	}
+
+	private int decodeParallelizationNumber(String value) {
+		int parallelNumber = -1;
+		if (VALUE_OPTIMAL.equals(value)) {
+			parallelNumber = -getOptimalParallelJobNum();
+		} else if (VALUE_UNLIMITED.equals(value)) {
+			parallelNumber = UNLIMITED_JOBS;
+		} else {
+			try {
+				parallelNumber = Integer.decode(value);
+			} catch (NumberFormatException e) {
+				ManagedBuilderCorePlugin.log(e);
+				parallelNumber = getOptimalParallelJobNum();
+			}
+			if (parallelNumber <= 0) {
+				// compatibility with legacy representation - it was that inconsistent
+				if (isInternalBuilder()) {
+					// "optimal" for Internal Builder
+					parallelNumber = -getOptimalParallelJobNum();
+				} else {
+					// unlimited for External Builder
+					parallelNumber = UNLIMITED_JOBS;
+				}
+			}
+		}
+		return parallelNumber;
+	}
+
 	/**
 	 * Initialize the builder information from the XML element 
 	 * specified in the argument
@@ -752,20 +791,18 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 		if (tmp != null)
 			stopOnErr = Boolean.valueOf(tmp);
 
-        if(element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD) != null)
+		tmp = element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD);
-        	parallelBuildCmd = SafeStringInterner.safeIntern(element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD));
+		if (tmp != null)
-        
+			parallelBuildCmd = SafeStringInterner.safeIntern(tmp);
-        tmp = element.getAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER);
-        if(tmp != null){
-        	try {
-        		parallelNum = Integer.decode(tmp);
-        	} catch (NumberFormatException e){
-        	}
-        }
 
 		tmp = element.getAttribute(ATTRIBUTE_PARALLEL_BUILD_ON);
-        if(tmp != null)
+		if (tmp != null) {
-        	parallelBuildOn = Boolean.valueOf(tmp);
+			isParallelBuildEnabled = Boolean.valueOf(tmp);
+			if (isParallelBuildEnabled) {
+				tmp = element.getAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER);
+				setParallelizationNumAttribute(decodeParallelizationNumber(element.getAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER)));
+			}
+		}
 
         ICStorageElement[] children = element.getChildren();
         for(int i = 0; i < children.length; i++){
@@ -873,12 +910,15 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 			element.setAttribute(ATTRIBUTE_IGNORE_ERR_CMD, ignoreErrCmd);
 		if (stopOnErr != null)
 			element.setAttribute(ATTRIBUTE_STOP_ON_ERR, stopOnErr.toString());
+
 		if (parallelBuildCmd != null)
 			element.setAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD, parallelBuildCmd);
-        if(parallelNum != null)
+
-        	element.setAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER, parallelNum.toString());
+		if (isParallelBuildEnabled != null)
-        if(parallelBuildOn != null)
+			element.setAttribute(ATTRIBUTE_PARALLEL_BUILD_ON, isParallelBuildEnabled.toString());
-        	element.setAttribute(ATTRIBUTE_PARALLEL_BUILD_ON, parallelBuildOn.toString());
+		if (isParallelBuildOn() && parallelNumberAttribute != null)
+			element.setAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER, encodeParallelizationNumber(parallelNumberAttribute));
+
 		// Note: build file generator cannot be specified in a project file because
 		//       an IConfigurationElement is needed to load it!
 		if (buildFileGeneratorElement != null) {
@@ -968,10 +1008,15 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 		if (getIgnoreErrCmdAttribute() != null)
 			element.setAttribute(ATTRIBUTE_IGNORE_ERR_CMD, getIgnoreErrCmdAttribute());
 		element.setAttribute(ATTRIBUTE_STOP_ON_ERR, Boolean.valueOf(isStopOnError()).toString());
-        if(getParrallelBuildCmd() != null)
+
-        	element.setAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD, getParrallelBuildCmd());
+		if (parallelBuildCmd != null)
-       	element.setAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER, new Integer(getParallelizationNumAttribute()).toString());
+			element.setAttribute(ATTRIBUTE_PARALLEL_BUILD_CMD, parallelBuildCmd);
-       	element.setAttribute(ATTRIBUTE_PARALLEL_BUILD_ON, Boolean.valueOf(isParallelBuildOn()).toString());
+
+		if (isParallelBuildEnabled != null)
+			element.setAttribute(ATTRIBUTE_PARALLEL_BUILD_ON, isParallelBuildEnabled.toString());
+		if (isParallelBuildOn() && parallelNumberAttribute != null)
+			element.setAttribute(ATTRIBUTE_PARALLELIZATION_NUMBER, encodeParallelizationNumber(parallelNumberAttribute));
+
 		// Note: build file generator cannot be specified in a project file because
 		//       an IConfigurationElement is needed to load it!
 		if (buildFileGeneratorElement != null) {
@@ -1042,16 +1087,17 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 	public String getArguments() {
 		String args = getArgumentsAttribute(); 
 		String stopOnErrCmd = getStopOnErrCmd(isStopOnError());
-		String parallelBuildCmd = isParallelBuildOn() ? getParallelizationCmd(getParallelizationNum()) : EMPTY_STRING;
+		int parallelNum = getParallelizationNum();
+		String parallelCmd = isParallelBuildOn() ? getParallelizationCmd(parallelNum) : EMPTY_STRING;
 		
 		String reversedStopOnErrCmd = getStopOnErrCmd(!isStopOnError());
-		String reversedParallelBuildCmd = !isParallelBuildOn() ? getParallelizationCmd(getParallelizationNum()) : EMPTY_STRING;
+		String reversedParallelBuildCmd = !isParallelBuildOn() ? getParallelizationCmd(parallelNum) : EMPTY_STRING;
 		
 		args = removeCmd(args, reversedStopOnErrCmd);
 		args = removeCmd(args, reversedParallelBuildCmd);
 		
 		args = addCmd(args, stopOnErrCmd);
-		args = addCmd(args, parallelBuildCmd);
+		args = addCmd(args, parallelCmd);
 
 		return args != null ? args.trim() : null;
 	}
@@ -1116,16 +1162,25 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 	
 	public String getParallelizationCmd(int num) {
 		String pattern = getParrallelBuildCmd();
-		if(pattern.length() == 0){
+		if (pattern.length() == 0 || num == 0) {
-			return EMPTY_STRING;
-		}if(num == 0){
 			return EMPTY_STRING;
 		}
-		
+		// "unlimited" number of jobs results in not adding the number to parallelization cmd
-		return processParallelPattern(pattern, num < 0, num);
+		// that behavior corresponds that of "make" flag "-j".
+		return processParallelPattern(pattern, num == UNLIMITED_JOBS, num);
 	}
 	
+	/**
+	 * This method turns the supplied pattern to parallelization command
+	 * 
+	 * It supports 2 kinds of pattern where "*" is replaced with number of jobs:
+	 * <li>Pattern 1 (supports "<b>-j*</b>"): "text*text" -> "text#text"</li>
+	 * <li>Pattern 2 (supports "<b>-[j*]</b>"): "text[text*text]text" -> "texttext#texttext</li>
+	 * <br>Where # is num or empty if {@code empty} is {@code true})
+	 */
 	private String processParallelPattern(String pattern, boolean empty, int num){
+		Assert.isTrue(num > 0);
+		
 		int start = pattern.indexOf(PARALLEL_PATTERN_NUM_START);
 		int end = -1;
 		boolean hasStartChar = false;
@@ -1238,10 +1293,10 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 		
 		if(newArgs != null){
 			String stopOnErrCmd = getStopOnErrCmd(isStopOnError());
-			String parallelBuildCmd = isParallelBuildOn() ? getParallelizationCmd(getParallelizationNum()) : EMPTY_STRING;
+			String parallelCmd = isParallelBuildOn() ? getParallelizationCmd(getParallelizationNum()) : EMPTY_STRING;
 
 			newArgs = removeCmd(newArgs, stopOnErrCmd);
-			newArgs = removeCmd(newArgs, parallelBuildCmd);
+			newArgs = removeCmd(newArgs, parallelCmd);
 		}
 		setArgumentsAttribute(newArgs);
 	}
@@ -1916,7 +1971,6 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 		return attr;
 	}
 	
-	
 	public String getFullBuildTarget() {
 		return getIncrementalBuildTarget();
 	}
@@ -2385,34 +2439,80 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 		return false;
 	}
 
-	public int getParallelizationNum() {
+	/**
-		if(supportsParallelBuild())
+	 * Returns the optimal number of parallel jobs.
-			return getParallelizationNumAttribute();
+	 * The number is the number of available processors on the machine.
-		return 1;
+	 * 
+	 * The function never returns number smaller than 1.
+	 */
+	public int getOptimalParallelJobNum() {
+		return Runtime.getRuntime().availableProcessors();
 	}
 	
+	/**
+	 * Returns the internal representation of maximum number of parallel jobs
+	 * to be used for a build.
+	 * Note that negative number represents "optimal" value.
+	 * 
+	 * The value of the number is encoded as follows:
+	 * <pre>
+	 *  Status       Returns
+	 * No parallel      1       
+	 * Optimal       -CPU# (negative number of processors) 
+	 * Specific        >0  (positive number)
+	 * Unlimited    Builder.UNLIMITED_JOBS
+	 * </pre>
+	 */
 	public int getParallelizationNumAttribute() {
-		if(parallelNum == null){
+		if (!isParallelBuildOn())
+			return 1;
+		
+		if(parallelNumberAttribute == null){
 			if(superClass != null){
 				return ((Builder)superClass).getParallelizationNumAttribute();
 			}
 			return 1;
 		}
-		return parallelNum.intValue();
+		return parallelNumberAttribute.intValue();
 	}
 
-	public void setParallelizationNum(int num) throws CoreException {
+	private void setParallelizationNumAttribute(int parallelNumber) {
-//		if(num == 0 || supportsParallelBuild()){
+		isParallelBuildEnabled = (parallelNumber != 1);
-			Integer newParallelNum = new Integer(num);
+		if (parallelNumber > 0) {
+			parallelNumberAttribute = parallelNumber;
+		} else {
+			// "optimal"
+			parallelNumberAttribute = -getOptimalParallelJobNum();
+		}
+	}
+
+	public int getParallelizationNum() {
+		return Math.abs(getParallelizationNumAttribute());
+	}
+
+	/**
+	 * {@inheritDoc}
+	 * 
+	 * @param jobs - maximum number of jobs. There are 2 special cases:
+	 *    <br>- any number <=0 is interpreted as setting "optimal" property,
+	 *    the value of the number itself is ignored in this case
+	 *    <br>- value 1 will turn parallel mode off.
+	 */
+	public void setParallelizationNum(int jobs) throws CoreException {
+		if (!supportsParallelBuild())
+			return;
+
+		if (parallelNumberAttribute == null || parallelNumberAttribute != jobs) {
 			String curCmd = getParallelizationCmd(getParallelizationNum());
 			String args = getArgumentsAttribute();
 			String updatedArgs = removeCmd(args, curCmd);
 			if (!updatedArgs.equals(args)) {
 				setArgumentsAttribute(updatedArgs);
 			}
-			parallelNum = newParallelNum;
+
+			setParallelizationNumAttribute(jobs);
 			setDirty(true);
-//		}
+		}
 	}
 
 	public boolean supportsParallelBuild() {
@@ -2457,29 +2557,33 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 	}
 
 	public boolean isParallelBuildOn() {
-		if(parallelBuildOn == null){
+		if (!supportsParallelBuild()) {
+			return false;
+		}
+		if (isParallelBuildEnabled == null) {
 			if (superClass != null) {
 				return getSuperClass().isParallelBuildOn();
 			}
 			return false;
 		}
-		return parallelBuildOn.booleanValue();
+		return isParallelBuildEnabled.booleanValue();
 	}
 
+	/**
+	 * {@inheritDoc}
+	 * 
+	 * @param on - the flag to enable or disable parallel mode.
+	 *    <br>{@code true} to enable, in this case the maximum number of jobs
+	 *      will be set to "optimal" number, see {@link #getOptimalParallelJobNum()}.
+	 *    <br>{@code false} to disable, the number of jobs will be set to 1.
+	 */
 	public void setParallelBuildOn(boolean on) throws CoreException {
-		if(isParallelBuildOn() == on)
+		if (on) {
-			return;
+			// set "optimal" jobs by default when enabling parallel build
-		if(on && !supportsParallelBuild())
+			setParallelizationNum(-1);
-			return;
+		} else {
-		
+			setParallelizationNum(1);
-		String curCmd = getParallelizationCmd(getParallelizationNum());
-		String args = getArgumentsAttribute();
-		String updatedArgs = removeCmd(args, curCmd);
-		if(!updatedArgs.equals(args)){
-			setArgumentsAttribute(updatedArgs);
 		}
-		parallelBuildOn = Boolean.valueOf(on);
-		setDirty(true);
 	}
 
 	public Set<String> contributeErrorParsers(Set<String> set){
@@ -2638,6 +2742,7 @@ public class Builder extends HoldsOptions implements IBuilder, IMatchKeyProvider
 	public boolean isExtensionBuildObject() {
 		return isExtensionElement();
 	}
+
 	@Override
 	public String toString() {
 		return getUniqueRealName();

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Configuration.java

@@ -752,7 +752,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 	 *  E L E M E N T   A T T R I B U T E   R E A D E R S   A N D   W R I T E R S
 	 */
 	
-	/* (non-Javadoc)
+	/**
 	 * Initialize the configuration information from an element in the 
 	 * manifest file or provided by a dynamicElementProvider
 	 * 
@@ -803,7 +803,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
         	isTest = Boolean.valueOf(tmp).booleanValue();
 	}
 	
-	/* (non-Javadoc)
+	/**
 	 * Initialize the configuration information from the XML element 
 	 * specified in the argument
 	 * 
@@ -1577,7 +1577,6 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
         } 
     } 
 	
- 
     /* (non-Javadoc) 
      * @see org.eclipse.cdt.core.build.managed.IConfiguration#setPostbuildStep(java.lang.String) 
      */ 
@@ -1785,7 +1784,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 		((FolderInfo)getRootFolderInfo()).resetOptionSettings();
 	}
 
-	/*
+	/**
 	 *  Create a resource configuration object for the passed-in file
 	 */
 	public IResourceConfiguration createResourceConfiguration(IFile file)
@@ -1932,7 +1931,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 		return getRootFolderInfo().getToolFromInputExtension(sourceExtension);
 	}
 
-	/*
+	/**
 	 * The resource delta passed to the builder is not always up-to-date
 	 * for the given configuration because between two builds of the same configuration
 	 * any number of other configuration builds may occur
@@ -2004,7 +2003,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 				prefs.getBoolean(pref, false) : defaultValue;
 	}
 */	
-	/*
+	/**
 	 * this method is used for enabling/disabling the internal builder
 	 * for the given configuration
 	 * 
@@ -2121,7 +2120,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 		return null;
 	}
 
-	/*
+	/**
 	 * returns whether the internal builder is enabled
 	 * @return boolean
 	 */
@@ -2129,7 +2128,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 		return getBuilder().isInternalBuilder(); 
 	}
 	
-	/*
+	/**
 	 * 
 	 * sets the Internal Builder mode
 	 * 
@@ -2144,7 +2143,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 		}
 	}
 
-	/*
+	/**
 	 * returns the Internal Builder mode
 	 * if true, internal builder will ignore build errors while building,
 	 * otherwise it will stop at the first build error
@@ -2156,73 +2155,73 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 	}
 	
 	/**
-	 * 
 	 * sets the Internal Builder Parallel mode
-	 * 
 	 * @param parallel if true, internal builder will use parallel mode 
+	 * 
+	 * @deprecated since CDT 9.0. Use {@link #setParallelDef(boolean)}
 	 */
+	@Deprecated
 	public void setInternalBuilderParallel(boolean parallel){
-		if(getInternalBuilderParallel() == parallel)
+		setParallelDef(parallel);
-			return;
-		
-		try {
-			getEditableBuilder().setParallelBuildOn(parallel);
-		} catch (CoreException e) {
-		}
 	}
 	
 	/**
 	 * returns the Internal Builder parallel mode
 	 * if true, internal builder will work in parallel mode 
 	 * otherwise it will use only one thread
-	 * 
 	 * @return boolean
+	 * 
+	 * @deprecated since CDT 9.0. Use {@link #getParallelDef()}
 	 */
+	@Deprecated
 	public boolean getInternalBuilderParallel(){
-		return getBuilder().isParallelBuildOn();
+		return getParallelDef();
 	}
 	
 	/**
-	 * @param parallel if true, internal builder will use parallel mode 
+	 * Set parallel execution mode for the configuration's builder.
+	 * @see Builder#setParallelBuildOn(boolean)
+	 * 
+	 * @param parallel - the flag to enable or disable parallel mode.
 	 */
 	public void setParallelDef(boolean parallel){
 		if(getParallelDef() == parallel)
 			return;
 		
-		int num = getParallelNumber();
+		try {
-		if(num != 0){
+			getEditableBuilder().setParallelBuildOn(parallel);
-			setParallelNumber(-num);
+		} catch (CoreException e) {
-		} else {
+			ManagedBuilderCorePlugin.log(e);
-			if(parallel){
-				setParallelNumber(-1);
-			} else {
-				setParallelNumber(1);
-			}
 		}
 	}
 	
 	/**
-	 * @return boolean
+	 * Check if the configuration's builder is operating in parallel mode.
+	 * @return {@code true} if parallel mode is enabled, {@code false} otherwise.
 	 */
 	public boolean getParallelDef(){
-		int num = getBuilder().getParallelizationNum();
+		return getBuilder().isParallelBuildOn();
-		return num <= 0;
 	}
 	
 	/**
-	 * sets number of Parallel threads
+	 * Sets maximum number of parallel threads/jobs to be used by builder.
-	 */
-	public void setParallelNumber(int n){
-		try {
-			getEditableBuilder().setParallelizationNum(n);
-		} catch (CoreException e) {
-		}
-	}
-	
-	/**
-	 * returns number of Parallel threads
 	 * 
-	 * @return int
+	 * @param jobs - maximum number of jobs or threads. For details how
+	 *    the number is interpreted see {@link Builder#setParallelizationNum(int)}.
+	 */
+	public void setParallelNumber(int jobs){
+		try {
+			getEditableBuilder().setParallelizationNum(jobs);
+		} catch (CoreException e) {
+			ManagedBuilderCorePlugin.log(e);
+		}
+	}
+	
+	/**
+	 * Returns maximum number of parallel threads/jobs used by the configuration's builder.
+	 * @see #setParallelDef(boolean)
+	 * 
+	 * @return - maximum number of parallel threads or jobs used by the builder.
 	 */
 	public int getParallelNumber(){
 		return getBuilder().getParallelizationNum();

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/GeneratedMakefileBuilder.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- *  Copyright (c) 2002, 2010 IBM Corporation and others.
+ *  Copyright (c) 2002, 2011 IBM Corporation and others.
  *  All rights reserved. This program and the accompanying materials
  *  are made available under the terms of the Eclipse Public License v1.0
  *  which accompanies this distribution, and is available at
@@ -906,7 +906,6 @@ public class GeneratedMakefileBuilder extends ACBuilder {
 			}
 
 			IPath makeCommand = new Path(makeCmd); 
-			if (makeCommand != null) {
 			String[] msgs = new String[2];
 			msgs[0] = makeCommand.toString();
 			msgs[1] = currentProject.getName();
@@ -1144,7 +1143,6 @@ public class GeneratedMakefileBuilder extends ACBuilder {
 				addBuilderMarkers(epm);
 				consoleOutStream.close();
 			}
-			}
 		} catch (Exception e) {
 			forgetLastBuiltState();
 		} finally {
@@ -1196,7 +1194,7 @@ public class GeneratedMakefileBuilder extends ACBuilder {
 			boolean resumeOnErr,
 			IProgressMonitor monitor) {
 		
-		boolean isParallel = ((Configuration)cfg).getInternalBuilderParallel();
+		boolean isParallel = ((Configuration)cfg).getParallelDef();
 		
 		// Get the project and make sure there's a monitor to cancel the build
 		IProject currentProject = cfg.getOwner().getProject();

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/MultiConfiguration.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2010 Intel Corporation and others.
+ * Copyright (c) 2007, 2011 Intel Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -44,6 +44,7 @@ import org.eclipse.cdt.managedbuilder.envvar.IConfigurationEnvironmentVariableSu
 import org.eclipse.cdt.managedbuilder.macros.IConfigurationBuildMacroSupplier;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IResource;
+import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.osgi.framework.Version;
@@ -253,15 +254,23 @@ public class MultiConfiguration extends MultiItemsHolder implements
 		return s;
 	}
 
-	/* (non-Javadoc)
+	/**
-	 * @see org.eclipse.cdt.managedbuilder.core.IConfiguration#getBuildArguments()
+	 * @return build arguments if the arguments for all configurations match
+	 *    or {@code null} otherwise.
 	 */
 	public String getBuildArguments() {
-		String s = fCfgs[0].getBuildArguments();
+		String args0 = fCfgs[0].getBuildArguments();
-		for (int i=1; i<fCfgs.length; i++)
+		if (args0 == null)
-			if (! s.equals(fCfgs[i].getBuildArguments()))
+			args0 = EMPTY_STR;
-				return EMPTY_STR;
+		
-		return s;
+		for (IConfiguration cfg : fCfgs) {
+			String args = cfg.getBuildArguments();
+			if (args == null)
+				args = EMPTY_STR;
+			if (!args0.equals(args))
+				return null;
+		}
+		return args0;
 	}
 
 	/* (non-Javadoc)
@@ -1090,49 +1099,49 @@ public class MultiConfiguration extends MultiItemsHolder implements
 	}
 
 	public boolean getParallelDef() {
-		for (int i=0; i<fCfgs.length; i++)
+		for (IConfiguration cfg : fCfgs) {
-			if (fCfgs[i] instanceof Configuration) {
+			if (cfg instanceof Configuration) {
-				if (!((Configuration)fCfgs[i]).getParallelDef())
+				if (!((Configuration)cfg).getParallelDef())
 					return false;
 			} else
 				return false;
+		}
 		return true; // all cfgs report true
 	}
 	
-	public void setParallelDef(boolean def) {
+	public void setParallelDef(boolean parallel) {
-		for (int i=0; i<fCfgs.length; i++)
+		for (IConfiguration cfg : fCfgs) {
-			if (fCfgs[i] instanceof Configuration)
+			if (cfg instanceof Configuration)
-				((Configuration)fCfgs[i]).setParallelDef(def);
+				((Configuration)cfg).setParallelDef(parallel);
+		}
 	}
 	
 	public int getParallelNumber() {
-		int res = -1;
+		int res = 0;
-		for (int i=0; i<fCfgs.length; i++)
+		for (IConfiguration cfg : fCfgs) {
-			if (fCfgs[i] instanceof Configuration) {
+			if (cfg instanceof Configuration) {
-				int x = ((Configuration)fCfgs[i]).getParallelNumber();
+				int num = ((Configuration)cfg).getParallelNumber();
-				if (res == -1) 
+				Assert.isTrue(num != 0); // can't be 0, see IMakeCommonBuildInfo.getParallelizationNum()
-					res = x;
+
-				else if (res != x)
+				if (res == 0) 
+					res = num;
+				else if (res != num)
 					return 0; // values are different !
 			} else
 				return 0;
-		return (res == -1 ? 0: res); // all cfgs report true
+		}
+		return res; // all cfgs report same value
 	}
 	
 	public void setParallelNumber(int num) {
-		for (int i=0; i<fCfgs.length; i++)
+		for (IConfiguration cfg : fCfgs) {
-			if (fCfgs[i] instanceof Configuration)
+			if (cfg instanceof Configuration)
-				((Configuration)fCfgs[i]).setParallelNumber(num);
+				((Configuration)cfg).setParallelNumber(num);
+		}
 	}
 	
 	public boolean getInternalBuilderParallel() {
-		for (int i=0; i<fCfgs.length; i++)
+		return getParallelDef();
-			if (fCfgs[i] instanceof Configuration) {
-				if (!((Configuration)fCfgs[i]).getInternalBuilderParallel())
-					return false;
-			} else
-				return false;
-		return true; // all cfgs report true
 	}
 	
 	public boolean isInternalBuilderEnabled() {

build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/newmake/core/IMakeCommonBuildInfo.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2004, 2010 QNX Software Systems and others.
+ * Copyright (c) 2004, 2011 QNX Software Systems and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -12,6 +12,7 @@ package org.eclipse.cdt.newmake.core;
 
 import java.util.Map;
 
+import org.eclipse.cdt.managedbuilder.internal.core.Builder;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 
@@ -42,10 +43,39 @@ public interface IMakeCommonBuildInfo {
 	void setStopOnError(boolean on) throws CoreException;
 	boolean supportsStopOnError(boolean on);
 
+	/**
+	 * @return the maximum number of parallel jobs to be used for build.
+	 */
 	int getParallelizationNum();
-	void setParallelizationNum(int num) throws CoreException;
+
+	/**
+	 * Sets maximum number of parallel threads/jobs to be used by builder.
+	 * Note that this number can be interpreted by builder in a special way.
+	 * @see Builder#setParallelizationNum(int)
+	 * 
+	 * @param jobs - maximum number of jobs.
+	 */
+	void setParallelizationNum(int jobs) throws CoreException;
+
+	/**
+	 * @return {@code true} if builder supports parallel build,
+	 *    {@code false} otherwise.
+	 */
+
 	boolean supportsParallelBuild();
+
+	/**
+	 * @return {@code true} if builder support for parallel build is enabled,
+	 *    {@code false} otherwise.
+	 */
 	boolean isParallelBuildOn();
+
+	/**
+	 * Set parallel execution mode for the builder.
+	 * @see Builder#setParallelBuildOn(boolean)
+	 * 
+	 * @param on - the flag to enable or disable parallel mode.
+	 */
 	void setParallelBuildOn(boolean on) throws CoreException;
 
 	boolean isDefaultBuildCmd();

build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/internal/ui/Messages.java

@@ -27,9 +27,10 @@ public class Messages extends NLS {
 	public static String BuilderSettingsTab_0;
 	public static String BuilderSettingsTab_1;
 	public static String BuilderSettingsTab_10;
-	public static String BuilderSettingsTab_11;
+	public static String BuilderSettingsTab_EnableParallelBuild;
-	public static String BuilderSettingsTab_12;
+	public static String BuilderSettingsTab_UseOptimalJobs;
-	public static String BuilderSettingsTab_13;
+	public static String BuilderSettingsTab_UseUnlimitedJobs;
+	public static String BuilderSettingsTab_UseParallelJobs;
 	public static String BuilderSettingsTab_14;
 	public static String BuilderSettingsTab_15;
 	public static String BuilderSettingsTab_16;

build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/internal/ui/Messages.properties

@@ -31,9 +31,10 @@ BuilderSettingsTab_7=&Generate Makefiles automatically
 BuilderSettingsTab_8=&Expand Env. Variable Refs in Makefiles
 BuilderSettingsTab_9=Build settings
 BuilderSettingsTab_10=Stop on first build error
-BuilderSettingsTab_11=Use parallel build
+BuilderSettingsTab_EnableParallelBuild=Enable parallel build
-BuilderSettingsTab_12=Use optimal jobs number
+BuilderSettingsTab_UseOptimalJobs=Use number of processors ({0})
-BuilderSettingsTab_13=Use parallel jobs: 
+BuilderSettingsTab_UseParallelJobs=Use parallel jobs: 
+BuilderSettingsTab_UseUnlimitedJobs=Use unlimited jobs
 BuilderSettingsTab_14=Workbench Build Behavior
 BuilderSettingsTab_15=Workbench build type:
 BuilderSettingsTab_16=Make build target:

build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildBehaviourTab.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2010  Intel Corporation and others.
+ * Copyright (c) 2007, 2011 Intel Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -11,6 +11,8 @@
  *******************************************************************************/
 package org.eclipse.cdt.managedbuilder.ui.properties;
 
+import java.text.MessageFormat;
+
 import org.eclipse.cdt.core.settings.model.ICConfigurationDescription;
 import org.eclipse.cdt.core.settings.model.ICMultiConfigDescription;
 import org.eclipse.cdt.core.settings.model.ICMultiItemsHolder;
@@ -18,7 +20,6 @@ import org.eclipse.cdt.core.settings.model.ICResourceDescription;
 import org.eclipse.cdt.managedbuilder.core.IBuilder;
 import org.eclipse.cdt.managedbuilder.core.IConfiguration;
 import org.eclipse.cdt.managedbuilder.core.IMultiConfiguration;
-import org.eclipse.cdt.managedbuilder.internal.buildmodel.BuildProcessManager;
 import org.eclipse.cdt.managedbuilder.internal.core.Builder;
 import org.eclipse.cdt.managedbuilder.internal.core.Configuration;
 import org.eclipse.cdt.managedbuilder.internal.core.MultiConfiguration;
@@ -51,6 +52,8 @@ import org.eclipse.swt.widgets.Widget;
  * @noinstantiate This class is not intended to be instantiated by clients.
  */
 public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
+	private static final int SPINNER_MAX_VALUE = 10000;
+	private static final int SPINNER_MIN_VALUE = 2;
 	
 	private static final int TRI_STATES_SIZE = 4;
 	// Widgets
@@ -58,9 +61,10 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 	private Button b_stopOnError; // 3
 	private Button b_parallel;    // 3
 
-	private Button b_parallelOpt;
+	private Button b_parallelOptimal;
-	private Button b_parallelNum;
+	private Button b_parallelSpecific;
-	private Spinner parallelProcesses;
+	private Button b_parallelUnlimited;
+	private Spinner s_parallelNumber;
 
 	private Label  title2;
 	private Button b_autoBuild; //3
@@ -70,11 +74,11 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 	private Button b_cmdClean; // 3
 	private Text   t_cmdClean;	
 
-	private IBuilder bldr;
+	private Builder bldr;
 	private IConfiguration icfg;
 	private boolean canModify = true;
 	
-	protected final int cpuNumber = BuildProcessManager.checkCPUNumber(); 
+	protected final int cpuNumber = Runtime.getRuntime().availableProcessors(); 
 	
 	@Override
 	public void createControls(Composite parent) {
@@ -110,7 +114,7 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 		gl.marginHeight = 0;
 		c2.setLayout(gl);
 		
-		b_parallel = setupCheck(c2, Messages.BuilderSettingsTab_11, 1, GridData.BEGINNING); 
+		b_parallel = setupCheck(c2, Messages.BuilderSettingsTab_EnableParallelBuild, 1, GridData.BEGINNING); 
 
 		Composite c3 = new Composite(g3, SWT.NONE);
 		setupControl(c3, 1, GridData.FILL_BOTH);
@@ -120,39 +124,60 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 		gl.marginHeight = 0;
 		c3.setLayout(gl);
 		
-		b_parallelOpt= new Button(c3, SWT.RADIO);
+		b_parallelOptimal= new Button(c3, SWT.RADIO);
-		b_parallelOpt.setText(Messages.BuilderSettingsTab_12); 
+		b_parallelOptimal.setText(MessageFormat.format(Messages.BuilderSettingsTab_UseOptimalJobs, 1)); 
-		setupControl(b_parallelOpt, 2, GridData.BEGINNING);
+		setupControl(b_parallelOptimal, 2, GridData.BEGINNING);
-		((GridData)(b_parallelOpt.getLayoutData())).horizontalIndent = 15;
+		((GridData)(b_parallelOptimal.getLayoutData())).horizontalIndent = 15;
-		b_parallelOpt.addSelectionListener(new SelectionAdapter() {
+		b_parallelOptimal.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent event) {
-				setParallelDef(b_parallelOpt.getSelection());
+				if (b_parallelOptimal.getSelection()) {
+					setParallelDef(true);
+					setParallelNumber(-1);
 					updateButtons();
+				}
 		 }});
 		
-		b_parallelNum= new Button(c3, SWT.RADIO);
+		b_parallelSpecific= new Button(c3, SWT.RADIO);
-		b_parallelNum.setText(Messages.BuilderSettingsTab_13); 
+		b_parallelSpecific.setText(Messages.BuilderSettingsTab_UseParallelJobs); 
-		setupControl(b_parallelNum, 1, GridData.BEGINNING);
+		setupControl(b_parallelSpecific, 1, GridData.BEGINNING);
-		((GridData)(b_parallelNum.getLayoutData())).horizontalIndent = 15;
+		((GridData)(b_parallelSpecific.getLayoutData())).horizontalIndent = 15;
-		b_parallelNum.addSelectionListener(new SelectionAdapter() {
+		b_parallelSpecific.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent event) {
-				setParallelDef(!b_parallelNum.getSelection());
+				if (b_parallelSpecific.getSelection()) {
+					setParallelDef(true);
+					setParallelNumber(s_parallelNumber.getSelection());
 					updateButtons();
+				}
 		 }});
 
-		parallelProcesses = new Spinner(c3, SWT.BORDER);
+		s_parallelNumber = new Spinner(c3, SWT.BORDER);
-		setupControl(parallelProcesses, 1, GridData.BEGINNING);
+		setupControl(s_parallelNumber, 1, GridData.BEGINNING);
-		parallelProcesses.setValues(cpuNumber, 1, 10000, 0, 1, 10);
+		s_parallelNumber.setValues(cpuNumber, SPINNER_MIN_VALUE, SPINNER_MAX_VALUE, 0, 1, 10);
-		parallelProcesses.addSelectionListener(new SelectionAdapter () {
+		s_parallelNumber.addSelectionListener(new SelectionAdapter () {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
-				setParallelNumber(parallelProcesses.getSelection());
+				setParallelDef(true);
+				setParallelNumber(s_parallelNumber.getSelection());
 				updateButtons();
 			}
 		});
 		
+		b_parallelUnlimited= new Button(c3, SWT.RADIO);
+		b_parallelUnlimited.setText(Messages.BuilderSettingsTab_UseUnlimitedJobs); 
+		setupControl(b_parallelUnlimited, 2, GridData.BEGINNING);
+		((GridData)(b_parallelUnlimited.getLayoutData())).horizontalIndent = 15;
+		b_parallelUnlimited.addSelectionListener(new SelectionAdapter() {
+			@Override
+			public void widgetSelected(SelectionEvent event) {
+				if (b_parallelUnlimited.getSelection()) {
+					setParallelDef(true);
+					setParallelNumber(Builder.UNLIMITED_JOBS);
+					updateButtons();
+				}
+		 }});
+		
 		// Workbench behaviour group
 		AccessibleListener makeTargetLabelAccessibleListener = new AccessibleAdapter() {
 			@Override
@@ -191,6 +216,7 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 	}
 
 	/**
+	 * Calculate enablements when multiple configurations selected on property page.
 	 * 
 	 * @return:
 	 * Mode 0:
@@ -202,55 +228,51 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 	 *    0: isStopOnError
 	 *    1: supportsStopOnError(true)
 	 *    2: bld.supportsStopOnError(false)  
-	 *    3: cfg.getInternalBuilderParallel()
+	 *    3: N/A
 	 * Mode 2:
 	 *    0: b.isAutoBuildEnable()
 	 *    1: b.isIncrementalBuildEnabled()
 	 *    2: b.isCleanBuildEnabled()
-	 *    3: getParallelDef()   
+	 *    3: N/A   
 	 */
-	 static int[] calc3states(ICPropertyProvider p, 
+	 static int[] calc3states(ICPropertyProvider p, IConfiguration mcfg, int mode) {
-			 IConfiguration c,
+		if (p.isMultiCfg() && mcfg instanceof ICMultiItemsHolder) { 
-			 int mode) {
+			boolean m0 = (mode == 0);
-		if (p.isMultiCfg() &&
+			boolean m1 = (mode == 1);
-			c instanceof ICMultiItemsHolder) 
-		{ 
-			boolean p0 = (mode == 0);
-			boolean p1 = (mode == 1);
 			
-			IConfiguration[] cfs = (IConfiguration[])((ICMultiItemsHolder)c).getItems();
+			IConfiguration[] cfgs = (IConfiguration[])((ICMultiItemsHolder)mcfg).getItems();
-			IBuilder b = cfs[0].getBuilder();
+			IBuilder bldr0 = cfgs[0].getBuilder();
 			int[] res = new int[TRI_STATES_SIZE];
-			boolean[] x = new boolean[TRI_STATES_SIZE];
+			boolean[] b = new boolean[TRI_STATES_SIZE];
-			x[0] = p0 ? b.isManagedBuildOn() : 
+			b[0] = m0 ? bldr0.isManagedBuildOn() : 
-				(p1 ? b.isStopOnError() : b.isAutoBuildEnable());
+				(m1 ? bldr0.isStopOnError() : bldr0.isAutoBuildEnable());
-			x[1] = p0 ? b.isDefaultBuildCmd(): 
+			b[1] = m0 ? bldr0.isDefaultBuildCmd(): 
-				(p1 ? b.supportsStopOnError(true) : b.isIncrementalBuildEnabled() );
+				(m1 ? bldr0.supportsStopOnError(true) : bldr0.isIncrementalBuildEnabled() );
-			x[2] = p0 ? b.canKeepEnvironmentVariablesInBuildfile() : 
+			b[2] = m0 ? bldr0.canKeepEnvironmentVariablesInBuildfile() : 
-				(p1 ? b.supportsStopOnError(false) : b.isCleanBuildEnabled());
+				(m1 ? bldr0.supportsStopOnError(false) : bldr0.isCleanBuildEnabled());
-			x[3] = p0 ? b.keepEnvironmentVariablesInBuildfile() : 
+			b[3] = m0 ? bldr0.keepEnvironmentVariablesInBuildfile() : false;
-				( p1 ? ((Configuration)cfs[0]).getInternalBuilderParallel() : getParallelDef(c));
+			for (int i=1; i<cfgs.length; i++) {
-			for (int i=1; i<cfs.length; i++) {
+				IBuilder bldr = cfgs[i].getBuilder();
-				b = cfs[i].getBuilder();
+				if (b[0] != (m0 ? bldr.isManagedBuildOn() : 
-				if (x[0] != (p0 ? b.isManagedBuildOn() : 
+						(m1 ? bldr.isStopOnError() : bldr.isAutoBuildEnable())))
-					(p1 ? b.isStopOnError() : b.isAutoBuildEnable())))
 					res[0] = TRI_UNKNOWN;
-				if (x[1] != (p0 ? b.isDefaultBuildCmd() : 
+				if (b[1] != (m0 ? bldr.isDefaultBuildCmd() : 
-					(p1 ? b.supportsStopOnError(true) : b.isIncrementalBuildEnabled())))
+						(m1 ? bldr.supportsStopOnError(true) : bldr.isIncrementalBuildEnabled())))
 					res[1] = TRI_UNKNOWN;
-				if (x[2] != (p0 ? b.canKeepEnvironmentVariablesInBuildfile() : 
+				if (b[2] != (m0 ? bldr.canKeepEnvironmentVariablesInBuildfile() : 
-					(p1 ? b.supportsStopOnError(false) : b.isCleanBuildEnabled())))
+						(m1 ? bldr.supportsStopOnError(false) : bldr.isCleanBuildEnabled())))
 					res[2] = TRI_UNKNOWN;
-				if (x[3] != (p0 ? b.keepEnvironmentVariablesInBuildfile() : 
+				if (b[3] != (m0 ? bldr.keepEnvironmentVariablesInBuildfile() : false)) {
-					(p1 ? ((Configuration)cfs[i]).getInternalBuilderParallel() : getParallelDef(c))))
 					res[3] = TRI_UNKNOWN;
 				}
+			}
 			for (int i=0; i<TRI_STATES_SIZE; i++) {
 				if (res[i] != TRI_UNKNOWN)
-					res[i] = x[i] ? TRI_YES : TRI_NO;
+					res[i] = b[i] ? TRI_YES : TRI_NO;
 			}
 			return res;
-		} else
+		}
+		
 		return null;
 	}
 	
@@ -259,10 +281,11 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 	 */
 	@Override
 	protected void updateButtons() {
-		bldr = icfg.getEditableBuilder();
+		bldr = (Builder) icfg.getEditableBuilder();
 		canModify = false;
 		int[] extStates = calc3states(page, icfg, 1);
 		
+		// Stop on error
 		if (extStates != null) {
 			setTriSelection(b_stopOnError, extStates[0]);
 			b_stopOnError.setEnabled(
@@ -274,39 +297,21 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 					bldr.supportsStopOnError(true) &&
 					bldr.supportsStopOnError(false));
 		}
-		// parallel
-		if (extStates == null) // no extended states
-			setTriSelection(b_parallel, getInternalBuilderParallel());
-		else
-			setTriSelection(b_parallel, extStates[3]);
 
-		int n = getParallelNumber();
-		if (n < 0) n = -n;
-		parallelProcesses.setSelection(n);
 
-		b_parallel.setVisible(bldr.supportsParallelBuild());
+		updateParallelBlock();
-		b_parallelOpt.setVisible(bldr.supportsParallelBuild());
-		b_parallelNum.setVisible(bldr.supportsParallelBuild());
-		parallelProcesses.setVisible(bldr.supportsParallelBuild());
 		
+		// Build commands
 		extStates = calc3states(page, icfg, 2);
-		if (extStates == null) {
+		if (extStates != null) {
-			setTriSelection(b_autoBuild, bldr.isAutoBuildEnable());
+			// multiple configurations selected
-			setTriSelection(b_cmdBuild, bldr.isIncrementalBuildEnabled());
-			setTriSelection(b_cmdClean, bldr.isCleanBuildEnabled());
-			b_parallelOpt.setSelection(getParallelDef(icfg));
-			b_parallelNum.setSelection(!getParallelDef(icfg));
-		} else {
 			setTriSelection(b_autoBuild, extStates[0]);
 			setTriSelection(b_cmdBuild, extStates[1]);
 			setTriSelection(b_cmdClean, extStates[2]);
-			if (extStates[3] == TRI_UNKNOWN) {
-				b_parallelOpt.setSelection(false);
-				b_parallelNum.setSelection(false);
 		} else {
-				b_parallelOpt.setSelection(getParallelDef(icfg));
+			setTriSelection(b_autoBuild, bldr.isAutoBuildEnable());
-				b_parallelNum.setSelection(!getParallelDef(icfg));
+			setTriSelection(b_cmdBuild, bldr.isIncrementalBuildEnabled());
-			}
+			setTriSelection(b_cmdClean, bldr.isCleanBuildEnabled());
 		}
 
 		if (page.isMultiCfg()) {
@@ -321,12 +326,6 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 		}
 		
 		boolean external = ! isInternalBuilderEnabled();
-		boolean parallel = b_parallel.getSelection();
-
-		b_parallelNum.setEnabled(parallel);
-		b_parallelOpt.setEnabled(parallel);
-		parallelProcesses.setEnabled(parallel & b_parallelNum.getSelection());
-		
 		title2.setVisible(external);
 		t_autoBuild.setVisible(external);
 		((Control)t_autoBuild.getData()).setVisible(external);
@@ -343,6 +342,79 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 		canModify = true;
 	}
 	
+	private void updateParallelBlock() {
+		// note: for multi-config selection bldr is from Active cfg
+
+		boolean isParallelSupported = bldr.supportsParallelBuild();
+		boolean isParallelOn = bldr.isParallelBuildOn();
+		int triSelection = isParallelOn ? TRI_YES : TRI_NO;
+
+		int parallelizationNumInternal = bldr.getParallelizationNumAttribute();
+		int optimalParallelNumber = bldr.getOptimalParallelJobNum();
+		int parallelNumber = bldr.getParallelizationNum();
+
+		if (icfg instanceof ICMultiItemsHolder) { 
+			IConfiguration[] cfgs = (IConfiguration[])((ICMultiItemsHolder)icfg).getItems();
+			boolean isAnyParallelOn = isParallelOn;
+			boolean isAnyParallelSupported = isParallelSupported;
+			boolean isParallelDiffers = false;
+			for (IConfiguration cfg : cfgs) {
+				Builder builder = (Builder) cfg.getBuilder();
+				isParallelDiffers = isParallelDiffers
+						|| builder.isParallelBuildOn() != isParallelOn
+						|| builder.getParallelizationNumAttribute() != parallelizationNumInternal;
+				
+				isAnyParallelOn = isAnyParallelOn || builder.isParallelBuildOn();
+				isAnyParallelSupported = isAnyParallelSupported || builder.supportsParallelBuild();
+			}
+
+			// reset initial display to "optimal" to enhance user experience:
+			if ((!isParallelSupported && isAnyParallelSupported) // parallel is supported by other than Active cfg
+					|| (!isParallelOn && isAnyParallelOn) // prevent showing the 1 job as parallel in the spinner
+				) {
+				isParallelSupported = true;
+				parallelizationNumInternal = -optimalParallelNumber;
+				parallelNumber = optimalParallelNumber;
+			}
+			if (isParallelSupported && isParallelDiffers) {
+				triSelection = TRI_UNKNOWN;
+			}
+		}
+		
+		b_parallel.setVisible(isParallelSupported);
+		b_parallelOptimal.setVisible(isParallelSupported);
+		b_parallelSpecific.setVisible(isParallelSupported);
+		b_parallelUnlimited.setVisible(isParallelSupported);
+		s_parallelNumber.setVisible(isParallelSupported);
+
+		if (isParallelSupported) {
+			setTriSelection(b_parallel, triSelection);
+			boolean isParallelSelected = b_parallel.getSelection();
+	
+			b_parallelOptimal.setText(MessageFormat.format(Messages.BuilderSettingsTab_UseOptimalJobs, optimalParallelNumber));
+			b_parallelOptimal.setEnabled(isParallelSelected);
+			b_parallelSpecific.setEnabled(isParallelSelected);
+			b_parallelUnlimited.setEnabled(isParallelSelected);
+	
+			if (isParallelSelected) {
+				boolean isOptimal = parallelizationNumInternal <= 0;
+				boolean isUnlimited = parallelizationNumInternal == Builder.UNLIMITED_JOBS;
+				
+				b_parallelOptimal.setSelection(isOptimal);
+				b_parallelSpecific.setSelection(!isOptimal && !isUnlimited);
+				b_parallelUnlimited.setSelection(isUnlimited);
+				s_parallelNumber.setEnabled(b_parallelSpecific.getEnabled() && b_parallelSpecific.getSelection());
+				s_parallelNumber.setSelection(s_parallelNumber.isEnabled() ? parallelNumber : optimalParallelNumber);
+			} else {
+				b_parallelOptimal.setSelection(true);
+				b_parallelSpecific.setSelection(false);
+				b_parallelUnlimited.setSelection(false);
+				s_parallelNumber.setEnabled(false);
+				s_parallelNumber.setSelection(optimalParallelNumber);
+			}
+		}
+	}
+
 	/**
 	 * Sets up text + corresponding button
 	 * Checkbox can be implemented either by Button or by TriButton
@@ -446,7 +518,7 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 			}
 			b2.setStopOnError(b1.isStopOnError());
 			b2.setParallelBuildOn(b1.isParallelBuildOn());
-			b2.setParallelizationNum(b1.getParallelizationNum());
+			b2.setParallelizationNum(((Builder) b1).getParallelizationNumAttribute());
 			if (b2.canKeepEnvironmentVariablesInBuildfile())
 				b2.setKeepEnvironmentVariablesInBuildfile(b1.keepEnvironmentVariablesInBuildfile());
 			((Builder)b2).setBuildPath(((Builder)b1).getBuildPathAttribute());
@@ -488,14 +560,6 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 		updateData(getResDesc());
 	}
 	
-	private static boolean getParallelDef(IConfiguration cfg) {
-		if (cfg instanceof Configuration) 
-			return ((Configuration)cfg).getParallelDef();
-		if (cfg instanceof IMultiConfiguration)
-			return ((IMultiConfiguration)cfg).getParallelDef();
-		return false;
-	}
-	
 	private void setParallelDef(boolean def) {
 		if (icfg instanceof Configuration) 
 			((Configuration)icfg).setParallelDef(def);
@@ -503,13 +567,6 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 			((IMultiConfiguration)icfg).setParallelDef(def);
 	}
 	
-	private int getParallelNumber() {
-		if (icfg instanceof Configuration) 
-			return ((Configuration)icfg).getParallelNumber();
-		if (icfg instanceof IMultiConfiguration)
-			return ((IMultiConfiguration)icfg).getParallelNumber();
-		return 0;
-	}
 	private void setParallelNumber(int num) {
 		if (icfg instanceof Configuration) 
 			((Configuration)icfg).setParallelNumber(num);
@@ -517,14 +574,6 @@ public class BuildBehaviourTab extends AbstractCBuildPropertyTab {
 			((IMultiConfiguration)icfg).setParallelNumber(num);
 	}
 	
-	private boolean getInternalBuilderParallel() {
-		if (icfg instanceof Configuration) 
-			return ((Configuration)icfg).getInternalBuilderParallel();
-		if (icfg instanceof IMultiConfiguration)
-			return ((IMultiConfiguration)icfg).getInternalBuilderParallel();
-		return false;
-	}
-
 	private boolean isInternalBuilderEnabled() {
 		if (icfg instanceof Configuration) 
 			return ((Configuration)icfg).isInternalBuilderEnabled();

build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuilderSettingsTab.java

@@ -171,7 +171,7 @@ public class BuilderSettingsTab extends AbstractCBuildPropertyTab {
 				canEnableInternalBuilder(true) &&
 				canEnableInternalBuilder(false));
 		
-		t_buildCmd.setText(getMC());
+		t_buildCmd.setText(getMakeCommand());
 		
 		if (page.isMultiCfg()) {
 			group_dir.setVisible(false);
@@ -293,11 +293,14 @@ public class BuilderSettingsTab extends AbstractCBuildPropertyTab {
 	/**
 	 * @return make command
 	 */
-	private String getMC() {
+	private String getMakeCommand() {
-		String makeCommand = bldr.getCommand();
+		String makeCommand = icfg.getBuildCommand();
-		String makeArgs = bldr.getArguments();
+		String makeArgs = icfg.getBuildArguments();
-		if (makeArgs != null) {	makeCommand += " " + makeArgs; } //$NON-NLS-1$
+
-		return makeCommand;
+		if (!(makeCommand.length() == 0) && makeArgs != null) {
+			return makeCommand + " " + makeArgs; //$NON-NLS-1$
+		}
+		return EMPTY_STR;
 	}
 	/**
 	 * Performs common settings for all controls