/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.internal.os;
import android.content.pm.PackageInfo;
import android.os.Build;
import android.os.SystemProperties;
import android.util.Log;
import dalvik.system.profiler.BinaryHprofWriter;
import dalvik.system.profiler.SamplingProfiler;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.Date;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicBoolean;
import libcore.io.IoUtils;
/**
* Integrates the framework with Dalvik's sampling profiler.
*/
public class SamplingProfilerIntegration {
private static final String TAG = "SamplingProfilerIntegration";
public static final String SNAPSHOT_DIR = "/data/snapshots";
private static final boolean enabled;
private static final Executor snapshotWriter;
private static final int samplingProfilerMilliseconds;
private static final int samplingProfilerDepth;
/** Whether or not a snapshot is being persisted. */
private static final AtomicBoolean pending = new AtomicBoolean(false);
static {
samplingProfilerMilliseconds = SystemProperties.getInt("persist.sys.profiler_ms", 0);
samplingProfilerDepth = SystemProperties.getInt("persist.sys.profiler_depth", 4);
if (samplingProfilerMilliseconds > 0) {
File dir = new File(SNAPSHOT_DIR);
dir.mkdirs();
// the directory needs to be writable to anybody to allow file writing
dir.setWritable(true, false);
// the directory needs to be executable to anybody to allow file creation
dir.setExecutable(true, false);
if (dir.isDirectory()) {
snapshotWriter = Executors.newSingleThreadExecutor(new ThreadFactory() {
public Thread newThread(Runnable r) {
return new Thread(r, TAG);
}
});
enabled = true;
Log.i(TAG, "Profiling enabled. Sampling interval ms: "
+ samplingProfilerMilliseconds);
} else {
snapshotWriter = null;
enabled = true;
Log.w(TAG, "Profiling setup failed. Could not create " + SNAPSHOT_DIR);
}
} else {
snapshotWriter = null;
enabled = false;
Log.i(TAG, "Profiling disabled.");
}
}
private static SamplingProfiler samplingProfiler;
private static long startMillis;
/**
* Is profiling enabled?
*/
public static boolean isEnabled() {
return enabled;
}
/**
* Starts the profiler if profiling is enabled.
*/
public static void start() {
if (!enabled) {
return;
}
if (samplingProfiler != null) {
Log.e(TAG, "SamplingProfilerIntegration already started at " + new Date(startMillis));
return;
}
ThreadGroup group = Thread.currentThread().getThreadGroup();
SamplingProfiler.ThreadSet threadSet = SamplingProfiler.newThreadGroupThreadSet(group);
samplingProfiler = new SamplingProfiler(samplingProfilerDepth, threadSet);
samplingProfiler.start(samplingProfilerMilliseconds);
startMillis = System.currentTimeMillis();
}
/**
* Writes a snapshot if profiling is enabled.
*/
public static void writeSnapshot(final String processName, final PackageInfo packageInfo) {
if (!enabled) {
return;
}
if (samplingProfiler == null) {
Log.e(TAG, "SamplingProfilerIntegration is not started");
return;
}
/*
* If we're already writing a snapshot, don't bother enqueueing another
* request right now. This will reduce the number of individual
* snapshots and in turn the total amount of memory consumed (one big
* snapshot is smaller than N subset snapshots).
*/
if (pending.compareAndSet(false, true)) {
snapshotWriter.execute(new Runnable() {
public void run() {
try {
writeSnapshotFile(processName, packageInfo);
} finally {
pending.set(false);
}
}
});
}
}
/**
* Writes the zygote's snapshot to internal storage if profiling is enabled.
*/
public static void writeZygoteSnapshot() {
if (!enabled) {
return;
}
writeSnapshotFile("zygote", null);
samplingProfiler.shutdown();
samplingProfiler = null;
startMillis = 0;
}
/**
* pass in PackageInfo to retrieve various values for snapshot header
*/
private static void writeSnapshotFile(String processName, PackageInfo packageInfo) {
if (!enabled) {
return;
}
samplingProfiler.stop();
/*
* We use the global start time combined with the process name
* as a unique ID. We can't use a counter because processes
* restart. This could result in some overlap if we capture
* two snapshots in rapid succession.
*/
String name = processName.replaceAll(":", ".");
String path = SNAPSHOT_DIR + "/" + name + "-" + startMillis + ".snapshot";
long start = System.currentTimeMillis();
OutputStream outputStream = null;
try {
outputStream = new BufferedOutputStream(new FileOutputStream(path));
PrintStream out = new PrintStream(outputStream);
generateSnapshotHeader(name, packageInfo, out);
if (out.checkError()) {
throw new IOException();
}
BinaryHprofWriter.write(samplingProfiler.getHprofData(), outputStream);
} catch (IOException e) {
Log.e(TAG, "Error writing snapshot to " + path, e);
return;
} finally {
IoUtils.closeQuietly(outputStream);
}
// set file readable to the world so that SamplingProfilerService
// can put it to dropbox
new File(path).setReadable(true, false);
long elapsed = System.currentTimeMillis() - start;
Log.i(TAG, "Wrote snapshot " + path + " in " + elapsed + "ms.");
samplingProfiler.start(samplingProfilerMilliseconds);
}
/**
* generate header for snapshots, with the following format
* (like an HTTP header but without the \r):
*
* Version: <version number of profiler>\n
* Process: <process name>\n
* Package: <package name, if exists>\n
* Package-Version: <version number of the package, if exists>\n
* Build: <fingerprint>\n
* \n
* <the actual snapshot content begins here...>
*/
private static void generateSnapshotHeader(String processName, PackageInfo packageInfo,
PrintStream out) {
// profiler version
out.println("Version: 3");
out.println("Process: " + processName);
if (packageInfo != null) {
out.println("Package: " + packageInfo.packageName);
out.println("Package-Version: " + packageInfo.versionCode);
}
out.println("Build: " + Build.FINGERPRINT);
// single blank line means the end of snapshot header.
out.println();
}
}
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