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Commit 915e6c11 authored by Zim's avatar Zim
Browse files

Populate binder trace txn names lazily 

Previously, for each binder interface, we populated a cache of all
txn codes to names on the first binder txn to that interface. This
skewed the binder txn latency significantly for the first txn to an
interface.

Now, we lazily populate the cache on each new binder txn.

Test: atest open-prebuilt-calculator --rebuild-module-info
--tf-template metric_post_processor=
google/template/postprocessors/metric-file-aggregate.xml
(neglible startup time diff locally)
Bug: 246650647

Change-Id: Ib569ebe34e7ef6bb4fa6e53defedcb33ed824308
parent dd3be999

core/java/android/os/Binder.java

+23 −18
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ import java.io.FileOutputStream; 
import java.io.IOException;

import java.io.PrintWriter;

import java.lang.reflect.Modifier;

import java.util.concurrent.atomic.AtomicReferenceArray;



/**

 * Base class for a remotable object, the core part of a lightweight
@@ -313,7 +314,7 @@ public class Binder implements IBinder { 
    private IInterface mOwner;

    @Nullable

    private String mDescriptor;

    private volatile String[] mTransactionTraceNames = null;

    private volatile AtomicReferenceArray<String> mTransactionTraceNames = null;

    private volatile String mSimpleDescriptor = null;

    private static final int TRANSACTION_TRACE_NAME_ID_LIMIT = 1024;
@@ -917,28 +918,32 @@ public class Binder implements IBinder { 
    @VisibleForTesting

    public final @NonNull String getTransactionTraceName(int transactionCode) {

        if (mTransactionTraceNames == null) {

            final String descriptor = getSimpleDescriptor();

            final int highestId = Math.min(getMaxTransactionId(), TRANSACTION_TRACE_NAME_ID_LIMIT);

            final String[] transactionNames = new String[highestId + 1];

            mSimpleDescriptor = getSimpleDescriptor();

            mTransactionTraceNames = new AtomicReferenceArray(highestId + 1);

        }



        final int index = transactionCode - FIRST_CALL_TRANSACTION;

        if (index < 0 || index >= mTransactionTraceNames.length()) {

            return mSimpleDescriptor + "#" + transactionCode;

        }



        String transactionTraceName = mTransactionTraceNames.getAcquire(index);

        if (transactionTraceName == null) {

            final String transactionName = getTransactionName(transactionCode);

            final StringBuffer buf = new StringBuffer();

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

                String transactionName = getTransactionName(i + FIRST_CALL_TRANSACTION);



            if (transactionName != null) {

                    buf.append(descriptor).append(':').append(transactionName);

                buf.append(mSimpleDescriptor).append(":").append(transactionName);

            } else {

                    buf.append(descriptor).append('#').append(i + FIRST_CALL_TRANSACTION);

                buf.append(mSimpleDescriptor).append("#").append(transactionCode);

            }

                transactionNames[i] = buf.toString();

                buf.setLength(0);

            }

            mSimpleDescriptor = descriptor;

            mTransactionTraceNames = transactionNames;

        }

        final int index = transactionCode - FIRST_CALL_TRANSACTION;

        if (index < 0 || index >= mTransactionTraceNames.length) {

            return mSimpleDescriptor + "#" + transactionCode;



            transactionTraceName = buf.toString();

            mTransactionTraceNames.setRelease(index, transactionTraceName);

        }

        return mTransactionTraceNames[index];



        return transactionTraceName;

    }



    private @NonNull String getSimpleDescriptor() {