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Commit 1f93a77b authored by Olivier Gaillard's avatar Olivier Gaillard
Browse files

Resolves transaction codes lazily when a dump is requested. 

This change allows to save:
- some memory by removing the method name from CallStat and CallSession
- some CPU by not calling binder.resolveCode for every binder call
at the expense of some hackiness (calling getDefaultTransactionCode
using reflection)

BinderCallsStats#getExportedCallsStats is now more costly to call but it
will be invoked only once a day only.

Test: unit test
Change-Id: Id4f933644c6da9d4aa2d0671db4ab80676eac1b0
parent bd493762

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

+25 −11
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ import com.android.internal.os.BinderInternal.CallSession; 
import com.android.internal.util.Preconditions;



import java.io.PrintWriter;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;
@@ -77,11 +79,10 @@ public class BinderCallsStats implements BinderInternal.Observer { 


    @Override

    public CallSession callStarted(Binder binder, int code) {

        return callStarted(binder.getClass(), code, binder.getTransactionName(code));

        return callStarted(binder.getClass(), code);

    }



    private CallSession callStarted(Class<? extends Binder> binderClass, int code,

            @Nullable String methodName) {

    private CallSession callStarted(Class<? extends Binder> binderClass, int code) {

        CallSession s = mCallSessionsPool.poll();

        if (s == null) {

            s = new CallSession();
@@ -89,7 +90,6 @@ public class BinderCallsStats implements BinderInternal.Observer { 


        s.binderClass = binderClass;

        s.transactionCode = code;

        s.methodName = methodName;

        s.exceptionThrown = false;

        s.cpuTimeStarted = -1;

        s.timeStarted = -1;
@@ -147,7 +147,6 @@ public class BinderCallsStats implements BinderInternal.Observer { 
                uidEntry.recordedCallCount++;



                callStat.recordedCallCount++;

                callStat.methodName = s.methodName;

                callStat.cpuTimeMicros += duration;

                callStat.maxCpuTimeMicros = Math.max(callStat.maxCpuTimeMicros, duration);

                callStat.latencyMicros += latencyDuration;
@@ -185,6 +184,22 @@ public class BinderCallsStats implements BinderInternal.Observer { 
        }

    }



    @Nullable

    private String resolveTransactionCode(Class<? extends Binder> binder, int transactionCode) {

        final Method getDefaultTransactionName;

        try {

            getDefaultTransactionName = binder.getMethod("getDefaultTransactionName", int.class);

        } catch (NoSuchMethodException e) {

            // The method might not be present for stubs not generated with AIDL.

            return null;

        }

        try {

            return (String) getDefaultTransactionName.invoke(null, transactionCode);

        } catch (IllegalAccessException | InvocationTargetException | ClassCastException e) {

            throw new RuntimeException(e);

        }

    }



    /**

     * This method is expensive to call.

     */
@@ -203,8 +218,11 @@ public class BinderCallsStats implements BinderInternal.Observer { 
                    ExportedCallStat exported = new ExportedCallStat();

                    exported.uid = entry.uid;

                    exported.className = stat.binderClass.getName();

                    exported.methodName = stat.methodName == null

                            ? String.valueOf(stat.transactionCode) : stat.methodName;

                    // TODO refactor in order to call resolveTransactionCode outside of the lock.

                    String methodName =

                            resolveTransactionCode(stat.binderClass, stat.transactionCode);

                    exported.methodName = methodName == null

                            ? String.valueOf(stat.transactionCode) : methodName;

                    exported.cpuTimeMicros = stat.cpuTimeMicros;

                    exported.maxCpuTimeMicros = stat.maxCpuTimeMicros;

                    exported.latencyMicros = stat.latencyMicros;
@@ -218,7 +236,6 @@ public class BinderCallsStats implements BinderInternal.Observer { 
                }

            }

        }



        return resultCallStats;

    }
@@ -386,9 +403,6 @@ public class BinderCallsStats implements BinderInternal.Observer { 
    public static class CallStat {

        public Class<? extends Binder> binderClass;

        public int transactionCode;

        // Method name might be null when we cannot resolve the transaction code. For instance, if

        // the binder was not generated by AIDL.

        public @Nullable String methodName;

        // Number of calls for which we collected data for. We do not record data for all the calls

        // when sampling is on.

        public long recordedCallCount;

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

+0 −2
Original line number Diff line number Diff line
@@ -78,8 +78,6 @@ public class BinderInternal { 
        public Class<? extends Binder> binderClass;

        // Binder transaction code.

        public int transactionCode;

        // Binder transaction method name.

        public String methodName;

        // CPU time at the beginning of the call.

        long cpuTimeStarted;

        // System time at the beginning of the call.

core/tests/coretests/src/com/android/internal/os/BinderCallsStatsTest.java

+23 −9
Original line number Diff line number Diff line
@@ -234,26 +234,40 @@ public class BinderCallsStatsTest { 
        assertEquals(0, callStats.maxCpuTimeMicros);

    }



    private static class BinderWithGetTransactionName extends Binder {

        public static String getDefaultTransactionName(int code) {

            return "resolved";

        }

    }



    @Test

    public void testTransactionCodeResolved() {

        TestBinderCallsStats bcs = new TestBinderCallsStats();

        bcs.setDetailedTracking(true);

        Binder binder = new Binder() {

            @Override

            public String getTransactionName(int code) {

                return "resolved";

            }

        };

        Binder binder = new BinderWithGetTransactionName();

        CallSession callSession = bcs.callStarted(binder, 1);

        bcs.time += 10;

        bcs.callEnded(callSession, REQUEST_SIZE, REPLY_SIZE);



        List<BinderCallsStats.CallStat> callStatsList =

                new ArrayList(bcs.getUidEntries().get(TEST_UID).getCallStatsList());

        assertEquals(1, callStatsList.get(0).transactionCode);

        List<BinderCallsStats.ExportedCallStat> callStatsList =

                bcs.getExportedCallStats();

        assertEquals("resolved", callStatsList.get(0).methodName);

    }



    @Test

    public void testResolvingCodeDoesNotThrowWhenMethodNotPresent() {

        TestBinderCallsStats bcs = new TestBinderCallsStats();

        bcs.setDetailedTracking(true);

        Binder binder = new Binder();

        CallSession callSession = bcs.callStarted(binder, 1);

        bcs.time += 10;

        bcs.callEnded(callSession, REQUEST_SIZE, REPLY_SIZE);



        List<BinderCallsStats.ExportedCallStat> callStatsList =

                bcs.getExportedCallStats();

        assertEquals("1", callStatsList.get(0).methodName);

    }



    @Test

    public void testParcelSize() {

        TestBinderCallsStats bcs = new TestBinderCallsStats();