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Commit 652973fc authored by Dianne Hackborn's avatar Dianne Hackborn
Browse files

Fix issue #17414533: update batterystats occasionally takes a couple... 

...hundred milliseconds.

Rework the locking so that no critical paths block on the cpu collection.

Change-Id: Ie615a033f7f8b523b67abee62c581d1a8fce324c
parent bb8c4834

core/java/com/android/internal/os/ProcessCpuTracker.java

+14 −10
Original line number Diff line number Diff line
@@ -64,7 +64,9 @@ public class ProcessCpuTracker { 


    /** Stores user time and system time in 100ths of a second. */

    private final long[] mProcessStatsData = new long[4];

    /** Stores user time and system time in 100ths of a second. */



    /** Stores user time and system time in 100ths of a second.  Used for

     * public API to retrieve CPU use for a process.  Must lock while in use. */

    private final long[] mSinglePidStatsData = new long[4];



    private static final int[] PROCESS_FULL_STATS_FORMAT = new int[] {
@@ -533,9 +535,10 @@ public class ProcessCpuTracker { 


    /**

     * Returns the total time (in clock ticks, or 1/100 sec) spent executing in

     * both user and system code.

     * both user and system code.  Safe to call without lock held.

     */

    public long getCpuTimeForPid(int pid) {

        synchronized (mSinglePidStatsData) {

            final String statFile = "/proc/" + pid + "/stat";

            final long[] statsData = mSinglePidStatsData;

            if (Process.readProcFile(statFile, PROCESS_STATS_FORMAT,
@@ -546,6 +549,7 @@ public class ProcessCpuTracker { 
            }

            return 0;

        }

    }



    /**

     * Returns the delta time (in clock ticks, or 1/100 sec) spent at each CPU

services/core/java/com/android/server/am/ActivityManagerService.java

+14 −11
Original line number Diff line number Diff line
@@ -1075,13 +1075,16 @@ public final class ActivityManagerService extends ActivityManagerNative 














    /**















     * Runtime CPU use collection thread.  This object's lock is used to













     * protect all related state.













     * perform synchronization with the thread (notifying it to run).















     */















    final Thread mProcessCpuThread;





























    /**













     * Used to collect process stats when showing not responding dialog.













     * Protected by mProcessCpuThread.













     * Used to collect per-process CPU use for ANRs, battery stats, etc.













     * Must acquire this object's lock when accessing it.













     * NOTE: this lock will be held while doing long operations (trawling













     * through all processes in /proc), so it should never be acquired by













     * any critical paths such as when holding the main activity manager lock.















     */















    final ProcessCpuTracker mProcessCpuTracker = new ProcessCpuTracker(















            MONITOR_THREAD_CPU_USAGE);










@@ -1595,7 +1598,7 @@ public final class ActivityManagerService extends ActivityManagerNative













                            infoMap.put(mi.pid, mi);















                        }















                        updateCpuStatsNow();













                        synchronized (mProcessCpuThread) {













                        synchronized (mProcessCpuTracker) {















                            final int N = mProcessCpuTracker.countStats();















                            for (int i=0; i<N; i++) {















                                ProcessCpuTracker.Stats st = mProcessCpuTracker.getStats(i);










@@ -1894,7 +1897,7 @@ public final class ActivityManagerService extends ActivityManagerNative













                if (memInfo != null) {















                    updateCpuStatsNow();















                    long nativeTotalPss = 0;













                    synchronized (mProcessCpuThread) {













                    synchronized (mProcessCpuTracker) {















                        final int N = mProcessCpuTracker.countStats();















                        for (int j=0; j<N; j++) {















                            ProcessCpuTracker.Stats st = mProcessCpuTracker.getStats(j);









@@ -1912,7 +1915,7 @@ public final class ActivityManagerService extends ActivityManagerNative













                        }















                    }















                    memInfo.readMemInfo();













                    synchronized (this) {













                    synchronized (ActivityManagerService.this) {















                        if (DEBUG_PSS) Slog.d(TAG, "Collected native and kernel memory in "















                                + (SystemClock.uptimeMillis()-start) + "ms");















                        mProcessStats.addSysMemUsageLocked(memInfo.getCachedSizeKb(),










@@ -2183,7 +2186,7 @@ public final class ActivityManagerService extends ActivityManagerNative













                return;















            }



























            synchronized (mActivityManagerService.mProcessCpuThread) {













            synchronized (mActivityManagerService.mProcessCpuTracker) {















                pw.print(mActivityManagerService.mProcessCpuTracker.printCurrentLoad());















                pw.print(mActivityManagerService.mProcessCpuTracker.printCurrentState(















                        SystemClock.uptimeMillis()));










@@ -2379,7 +2382,7 @@ public final class ActivityManagerService extends ActivityManagerNative













    }





























    void updateCpuStatsNow() {













        synchronized (mProcessCpuThread) {













        synchronized (mProcessCpuTracker) {















            mProcessCpuMutexFree.set(false);















            final long now = SystemClock.uptimeMillis();















            boolean haveNewCpuStats = false;










@@ -5074,7 +5077,7 @@ public final class ActivityManagerService extends ActivityManagerNative













        String cpuInfo = null;















        if (MONITOR_CPU_USAGE) {















            updateCpuStatsNow();













            synchronized (mProcessCpuThread) {













            synchronized (mProcessCpuTracker) {















                cpuInfo = mProcessCpuTracker.printCurrentState(anrTime);















            }















            info.append(processCpuTracker.printCurrentLoad());










@@ -13700,7 +13703,7 @@ public final class ActivityManagerService extends ActivityManagerNative













                    findPid = Integer.parseInt(args[opti]);















                } catch (NumberFormatException e) {















                }













                synchronized (mProcessCpuThread) {













                synchronized (mProcessCpuTracker) {















                    final int N = mProcessCpuTracker.countStats();















                    for (int i=0; i<N; i++) {















                        ProcessCpuTracker.Stats st = mProcessCpuTracker.getStats(i);










@@ -13862,7 +13865,7 @@ public final class ActivityManagerService extends ActivityManagerNative













            // If we are showing aggregations, also look for native processes to















            // include so that our aggregations are more accurate.















            updateCpuStatsNow();













            synchronized (mProcessCpuThread) {













            synchronized (mProcessCpuTracker) {















                final int N = mProcessCpuTracker.countStats();















                for (int i=0; i<N; i++) {















                    ProcessCpuTracker.Stats st = mProcessCpuTracker.getStats(i);

























services/core/java/com/android/server/am/ActivityStack.java



+3
−8




























Original line number
Diff line number
Diff line








@@ -1042,11 +1042,8 @@ final class ActivityStack {





























            if (prev.app != null && prev.cpuTimeAtResume > 0















                    && mService.mBatteryStatsService.isOnBattery()) {













                long diff;













                synchronized (mService.mProcessCpuThread) {













                    diff = mService.mProcessCpuTracker.getCpuTimeForPid(prev.app.pid)













                long diff = mService.mProcessCpuTracker.getCpuTimeForPid(prev.app.pid)















                        - prev.cpuTimeAtResume;













                }















                if (diff > 0) {















                    BatteryStatsImpl bsi = mService.mBatteryStatsService.getActiveStatistics();















                    synchronized (bsi) {










@@ -1097,9 +1094,7 @@ final class ActivityStack {













        // TODO: To be more accurate, the mark should be before the onCreate,















        //       not after the onResume. But for subsequent starts, onResume is fine.















        if (next.app != null) {













            synchronized (mService.mProcessCpuThread) {















            next.cpuTimeAtResume = mService.mProcessCpuTracker.getCpuTimeForPid(next.app.pid);













            }















        } else {















            next.cpuTimeAtResume = 0; // Couldn't get the cpu time of process















        }