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/*
* 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 dalvik.system.SamplingProfiler;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import android.util.Log;
import android.os.*;
/**
* Integrates the framework with Dalvik's sampling profiler.
*/
public class SamplingProfilerIntegration {
private static final String TAG = "SamplingProfilerIntegration";
private static final boolean enabled;
private static final Executor snapshotWriter;
static {
enabled = "1".equals(SystemProperties.get("persist.sampling_profiler"));
if (enabled) {
snapshotWriter = Executors.newSingleThreadExecutor();
Log.i(TAG, "Profiler is enabled.");
} else {
snapshotWriter = null;
Log.i(TAG, "Profiler is disabled.");
}
}
/**
* Is profiling enabled?
*/
public static boolean isEnabled() {
return enabled;
}
/**
* Starts the profiler if profiling is enabled.
*/
public static void start() {
if (!enabled) return;
SamplingProfiler.getInstance().start(10);
}
/** Whether or not we've created the snapshots dir. */
static boolean dirMade = false;
/** Whether or not a snapshot is being persisted. */
static volatile boolean pending;
/**
* Writes a snapshot to the SD card if profiling is enabled.
*/
public static void writeSnapshot(final String name) {
if (!enabled) return;
/*
* If we're already writing a snapshot, don't bother enqueing 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) {
pending = true;
snapshotWriter.execute(new Runnable() {
public void run() {
String dir =
Environment.getExternalStorageDirectory().getPath() + "/snapshots";
if (!dirMade) {
new File(dir).mkdirs();
if (new File(dir).isDirectory()) {
dirMade = true;
} else {
Log.w(TAG, "Creation of " + dir + " failed.");
return;
}
}
try {
writeSnapshot(dir, name);
} finally {
pending = false;
}
}
});
}
}
/**
* Writes the zygote's snapshot to internal storage if profiling is enabled.
*/
public static void writeZygoteSnapshot() {
if (!enabled) return;
String dir = "/data/zygote/snapshots";
new File(dir).mkdirs();
writeSnapshot(dir, "zygote");
}
private static void writeSnapshot(String dir, String name) {
byte[] snapshot = SamplingProfiler.getInstance().snapshot();
if (snapshot == null) {
return;
}
/*
* We use the current time 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.
*/
long start = System.currentTimeMillis();
String path = dir + "/" + name.replace(':', '.') + "-" +
+ System.currentTimeMillis() + ".snapshot";
try {
// Try to open the file a few times. The SD card may not be mounted.
FileOutputStream out;
int count = 0;
while (true) {
try {
out = new FileOutputStream(path);
break;
} catch (FileNotFoundException e) {
if (++count > 3) {
Log.e(TAG, "Could not open " + path + ".");
return;
}
// Sleep for a bit and then try again.
try {
Thread.sleep(2500);
} catch (InterruptedException e1) { /* ignore */ }
}
}
try {
out.write(snapshot);
} finally {
out.close();
}
long elapsed = System.currentTimeMillis() - start;
Log.i(TAG, "Wrote snapshot for " + name
+ " in " + elapsed + "ms.");
} catch (IOException e) {
Log.e(TAG, "Error writing snapshot.", e);
}
}
}
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