--- /dev/null
+package org.simantics.workbench.internal;
+
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Status;
+import org.eclipse.core.runtime.jobs.Job;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.SWTException;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Event;
+import org.eclipse.swt.widgets.Listener;
+import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.application.IWorkbenchConfigurer;
+import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
+import org.eclipse.ui.internal.ide.Policy;
+
+/**
+ * The idle helper detects when the system is idle in order to perform garbage
+ * collection in a way that minimizes impact on responsiveness of the UI.
+ * The algorithm for determining when to perform a garbage collection
+ * is as follows:
+ *
+ * - Never gc if there is a test harness present
+ * - Don't gc if background jobs are running
+ * - Don't gc if the keyboard or mouse have been active within IDLE_INTERVAL
+ * - Don't gc if there has been a GC within the minimum gc interval (system property PROP_GC_INTERVAL)
+ * - After a gc, don't gc again until (duration * GC_DELAY_MULTIPLIER) has elapsed.
+ * For example, if a GC takes 100ms and the multiplier is 60, don't gc for at least five seconds
+ * - Never gc again if any single gc takes longer than system property PROP_GC_MAX
+ */
+class IDEIdleHelper {
+
+ /**
+ * The default minimum time between garbage collections.
+ */
+ private static final int DEFAULT_GC_INTERVAL = 60000;
+
+ /**
+ * The default maximum duration for a garbage collection, beyond which
+ * the explicit gc mechanism is automatically disabled.
+ */
+ private static final int DEFAULT_GC_MAX = 8000;
+
+ /**
+ * The multiple of the last gc duration before we will consider doing
+ * another one.
+ */
+ private static final int GC_DELAY_MULTIPLIER = 60;
+
+ /**
+ * The time interval of no keyboard or mouse events after which the system
+ * is considered idle.
+ */
+ private static final int IDLE_INTERVAL = 5000;
+
+ /**
+ * The name of the boolean system property that specifies whether explicit
+ * garbage collection is enabled.
+ */
+ private static final String PROP_GC = "ide.gc"; //$NON-NLS-1$
+
+ /**
+ * The name of the integer system property that specifies the minimum time
+ * interval in milliseconds between garbage collections.
+ */
+ private static final String PROP_GC_INTERVAL = "ide.gc.interval"; //$NON-NLS-1$
+
+ /**
+ * The name of the integer system property that specifies the maximum
+ * duration for a garbage collection. If this duration is ever exceeded, the
+ * explicit gc mechanism is disabled for the remainder of the session.
+ */
+ private static final String PROP_GC_MAX = "ide.gc.max"; //$NON-NLS-1$
+
+ protected IWorkbenchConfigurer configurer;
+
+ private Listener idleListener;
+
+ /**
+ * The last time we garbage collected.
+ */
+ private long lastGC = System.currentTimeMillis();
+
+ /**
+ * The maximum gc duration. If this value is exceeded, the
+ * entire explicit gc mechanism is disabled.
+ */
+ private int maxGC = DEFAULT_GC_MAX;
+ /**
+ * The minimum time interval until the next garbage collection
+ */
+ private int minGCInterval = DEFAULT_GC_INTERVAL;
+
+ /**
+ * The time interval until the next garbage collection
+ */
+ private int nextGCInterval = DEFAULT_GC_INTERVAL;
+
+ private Job gcJob;
+
+ private Runnable handler;
+
+ /**
+ * Creates and initializes the idle handler
+ * @param aConfigurer The workbench configurer.
+ */
+ IDEIdleHelper(IWorkbenchConfigurer aConfigurer) {
+ this.configurer = aConfigurer;
+ //don't gc while running tests because performance tests are sensitive to timing (see bug 121562)
+ if (PlatformUI.getTestableObject().getTestHarness() != null) {
+ return;
+ }
+ String enabled = System.getProperty(PROP_GC);
+ //gc is turned on by default if property is missing
+ if (enabled != null && enabled.equalsIgnoreCase(Boolean.FALSE.toString())) {
+ return;
+ }
+ //init gc interval
+ Integer prop = Integer.getInteger(PROP_GC_INTERVAL);
+ if (prop != null && prop.intValue() >= 0) {
+ minGCInterval = nextGCInterval = prop.intValue();
+ }
+
+ //init max gc interval
+ prop = Integer.getInteger(PROP_GC_MAX);
+ if (prop != null) {
+ maxGC = prop.intValue();
+ }
+
+ createGarbageCollectionJob();
+
+ //hook idle handler
+ final Display display = configurer.getWorkbench().getDisplay();
+ handler = new Runnable() {
+ public void run() {
+ if (!display.isDisposed() && !configurer.getWorkbench().isClosing()) {
+ int nextInterval;
+ final long start = System.currentTimeMillis();
+ //don't garbage collect if background jobs are running
+ if (!Job.getJobManager().isIdle()) {
+ nextInterval = IDLE_INTERVAL;
+ } else if ((start - lastGC) < nextGCInterval) {
+ //don't garbage collect if we have collected within the specific interval
+ nextInterval = nextGCInterval - (int) (start - lastGC);
+ } else {
+ gcJob.schedule();
+ nextInterval = minGCInterval;
+ }
+ display.timerExec(nextInterval, this);
+ }
+ }
+ };
+ idleListener = new Listener() {
+ public void handleEvent(Event event) {
+ display.timerExec(IDLE_INTERVAL, handler);
+ }
+ };
+ display.addFilter(SWT.KeyUp, idleListener);
+ display.addFilter(SWT.MouseUp, idleListener);
+ }
+
+ /**
+ * Creates the job that performs garbage collection
+ */
+ private void createGarbageCollectionJob() {
+ gcJob = new Job(IDEWorkbenchMessages.IDEIdleHelper_backgroundGC) {
+ protected IStatus run(IProgressMonitor monitor) {
+ final Display display = configurer.getWorkbench().getDisplay();
+ if (display != null && !display.isDisposed()) {
+ final long start = System.currentTimeMillis();
+ System.gc();
+ System.runFinalization();
+ lastGC = start;
+ final int duration = (int) (System.currentTimeMillis() - start);
+ if (Policy.DEBUG_GC) {
+ System.out.println("Explicit GC took: " + duration); //$NON-NLS-1$
+ }
+ if (duration > maxGC) {
+ if (Policy.DEBUG_GC) {
+ System.out.println("Further explicit GCs disabled due to long GC"); //$NON-NLS-1$
+ }
+ shutdown();
+ } else {
+ //if the gc took a long time, ensure the next gc doesn't happen for awhile
+ nextGCInterval = Math.max(minGCInterval, GC_DELAY_MULTIPLIER * duration);
+ if (Policy.DEBUG_GC) {
+ System.out.println("Next GC to run in: " + nextGCInterval); //$NON-NLS-1$
+ }
+ }
+ }
+ return Status.OK_STATUS;
+ }
+ };
+ gcJob.setSystem(true);
+ }
+
+ /**
+ * Shuts down the idle helper, removing any installed listeners, etc.
+ */
+ void shutdown() {
+ if (idleListener == null) {
+ return;
+ }
+ final Display display = configurer.getWorkbench().getDisplay();
+ if (display != null && !display.isDisposed()) {
+ try {
+ display.asyncExec(new Runnable() {
+ public void run() {
+ display.timerExec(-1, handler);
+ display.removeFilter(SWT.KeyUp, idleListener);
+ display.removeFilter(SWT.MouseUp, idleListener);
+ }
+ });
+ } catch (SWTException ex) {
+ // ignore (display might be disposed)
+ }
+ }
+ }
+}
Code Review / simantics / platform.git / blobdiff