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Commit 711859d0 authored by Mohamad Mahmoud's avatar Mohamad Mahmoud
Browse files

Move dumpAnrStateLocked off the critical ANR path 

Shift the execution of dumpAnrStateLocked to the foreground thread to allow concurrent operation with the stack dump for the ANRing process.
This significantly reduces the time to initiate the stack dump (~70 ms on a Pixel 5 device)for input dispatching timeout ANRs.

This change addresses a major source of nativePollOnce (message queue idle) ANRs, which is the latency in initiating stack dumps.

Bug: 272292150
Test: make sure dumpAnrStateLocked behaves as expected
Test: Manual test: make sure the duration array has the correct value
Test: atest FrameworksServicesTests:AnrHelperTest

Change-Id: Ic7a2391c365501b4b4b19c0fbc4d3f22e37f1918
parent 53466c00

core/java/com/android/internal/os/anr/AnrLatencyTracker.java

+17 −1
Original line number Diff line number Diff line
@@ -118,6 +118,9 @@ public class AnrLatencyTracker implements AutoCloseable { 
    private boolean mIsSkipped = false;

    private boolean mCopyingFirstPidSucceeded = false;



    private long mPreDumpIfLockTooSlowStartUptime;

    private long mPreDumpIfLockTooSlowDuration = 0;



    private final int mAnrRecordPlacedOnQueueCookie =

            sNextAnrRecordPlacedOnQueueCookieGenerator.incrementAndGet();
@@ -401,6 +404,17 @@ public class AnrLatencyTracker implements AutoCloseable { 
        Trace.traceCounter(TRACE_TAG_ACTIVITY_MANAGER, "anrRecordsQueueSize", queueSize);

    }



    /** Records the start of AnrController#preDumpIfLockTooSlow. */

    public void preDumpIfLockTooSlowStarted() {

        mPreDumpIfLockTooSlowStartUptime = getUptimeMillis();

    }



    /** Records the end of AnrController#preDumpIfLockTooSlow. */

    public void preDumpIfLockTooSlowEnded() {

        mPreDumpIfLockTooSlowDuration +=

                getUptimeMillis() - mPreDumpIfLockTooSlowStartUptime;

    }



    /** Records a skipped ANR in ProcessErrorStateRecord#appNotResponding. */

    public void anrSkippedProcessErrorStateRecordAppNotResponding() {

        anrSkipped("appNotResponding");
@@ -415,7 +429,7 @@ public class AnrLatencyTracker implements AutoCloseable { 
     * Returns latency data as a comma separated value string for inclusion in ANR report.

     */

    public String dumpAsCommaSeparatedArrayWithHeader() {

        return "DurationsV3: " + mAnrTriggerUptime

        return "DurationsV4: " + mAnrTriggerUptime

                /* triggering_to_app_not_responding_duration = */

                + "," + (mAppNotRespondingStartUptime -  mAnrTriggerUptime)

                /* app_not_responding_duration = */
@@ -464,6 +478,8 @@ public class AnrLatencyTracker implements AutoCloseable { 
                + "," + mEarlyDumpStatus

                /* copying_first_pid_succeeded = */

                + "," + (mCopyingFirstPidSucceeded ? 1 : 0)

                /* preDumpIfLockTooSlow_duration = */

                + "," + mPreDumpIfLockTooSlowDuration

                + "\n\n";



    }

services/core/java/com/android/server/wm/AnrController.java

+25 −12
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ import android.util.SparseArray; 
import android.view.InputApplicationHandle;



import com.android.internal.os.TimeoutRecord;

import com.android.server.FgThread;

import com.android.server.am.StackTracesDumpHelper;

import com.android.server.criticalevents.CriticalEventLog;
@@ -68,7 +69,9 @@ class AnrController { 
            TimeoutRecord timeoutRecord) {

        try {

            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "notifyAppUnresponsive()");

            timeoutRecord.mLatencyTracker.preDumpIfLockTooSlowStarted();

            preDumpIfLockTooSlow();

            timeoutRecord.mLatencyTracker.preDumpIfLockTooSlowEnded();

            final ActivityRecord activity;

            timeoutRecord.mLatencyTracker.waitingOnGlobalLockStarted();

            boolean blamePendingFocusRequest = false;
@@ -108,7 +111,7 @@ class AnrController { 
                if (!blamePendingFocusRequest) {

                    Slog.i(TAG_WM, "ANR in " + activity.getName() + ".  Reason: "

                            + timeoutRecord.mReason);

                    dumpAnrStateLocked(activity, null /* windowState */, timeoutRecord.mReason);

                    dumpAnrStateAsync(activity, null /* windowState */, timeoutRecord.mReason);

                    mUnresponsiveAppByDisplay.put(activity.getDisplayId(), activity);

                }

            }
@@ -159,7 +162,9 @@ class AnrController { 
     */

    private boolean notifyWindowUnresponsive(@NonNull IBinder inputToken,

            TimeoutRecord timeoutRecord) {

        timeoutRecord.mLatencyTracker.preDumpIfLockTooSlowStarted();

        preDumpIfLockTooSlow();

        timeoutRecord.mLatencyTracker.preDumpIfLockTooSlowEnded();

        final int pid;

        final boolean aboveSystem;

        final ActivityRecord activity;
@@ -178,7 +183,7 @@ class AnrController { 
                    ? windowState.mActivityRecord : null;

            Slog.i(TAG_WM, "ANR in " + target + ". Reason:" + timeoutRecord.mReason);

            aboveSystem = isWindowAboveSystem(windowState);

            dumpAnrStateLocked(activity, windowState, timeoutRecord.mReason);

            dumpAnrStateAsync(activity, windowState, timeoutRecord.mReason);

        }

        if (activity != null) {

            activity.inputDispatchingTimedOut(timeoutRecord, pid);
@@ -197,7 +202,7 @@ class AnrController { 
        timeoutRecord.mLatencyTracker.waitingOnGlobalLockStarted();

        synchronized (mService.mGlobalLock) {

            timeoutRecord.mLatencyTracker.waitingOnGlobalLockEnded();

            dumpAnrStateLocked(null /* activity */, null /* windowState */, timeoutRecord.mReason);

            dumpAnrStateAsync(null /* activity */, null /* windowState */, timeoutRecord.mReason);

        }



        // We cannot determine the z-order of the window, so place the anr dialog as high
@@ -351,15 +356,23 @@ class AnrController { 


    }



    private void dumpAnrStateLocked(ActivityRecord activity, WindowState windowState,

    /**

     * Executes asynchronously on the fg thread not to block the stack dump for

     * the ANRing processes.

     */

    private void dumpAnrStateAsync(ActivityRecord activity, WindowState windowState,

            String reason) {

        FgThread.getExecutor().execute(() -> {

            try {

                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "dumpAnrStateLocked()");

                synchronized (mService.mGlobalLock) {

                    mService.saveANRStateLocked(activity, windowState, reason);

                    mService.mAtmService.saveANRState(reason);

                }

            } finally {

                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

            }

        });

    }



    private boolean isWindowAboveSystem(@NonNull WindowState windowState) {