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/*
* Copyright (C) 2008 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.server.am;
import android.util.Slog;
import java.io.*;
import java.util.Arrays;
/**
* Monitors device resources periodically for some period of time. Useful for
* tracking down performance problems.
*/
class DeviceMonitor {
private static final String LOG_TAG = DeviceMonitor.class.getName();
/** Number of samples to take. */
private static final int SAMPLE_COUNT = 10;
/** Time to wait in ms between samples. */
private static final int INTERVAL = 1000;
/** Time to wait in ms between samples. */
private static final int MAX_FILES = 30;
private final byte[] buffer = new byte[1024];
/** Is the monitor currently running? */
private boolean running = false;
private DeviceMonitor() {
new Thread() {
public void run() {
monitor();
}
}.start();
}
/**
* Loops continuously. Pauses until someone tells us to start monitoring.
*/
@SuppressWarnings("InfiniteLoopStatement")
private void monitor() {
while (true) {
waitForStart();
purge();
for (int i = 0; i < SAMPLE_COUNT; i++) {
try {
dump();
} catch (IOException e) {
Slog.w(LOG_TAG, "Dump failed.", e);
}
pause();
}
stop();
}
}
private static final File PROC = new File("/proc");
private static final File BASE = new File("/data/anr/");
static {
if (!BASE.isDirectory() && !BASE.mkdirs()) {
throw new AssertionError("Couldn't create " + BASE + ".");
}
}
private static final File[] PATHS = {
new File(PROC, "zoneinfo"),
new File(PROC, "interrupts"),
new File(PROC, "meminfo"),
new File(PROC, "slabinfo"),
};
/**
* Deletes old files.
*/
private void purge() {
File[] files = BASE.listFiles();
int count = files.length - MAX_FILES;
if (count > 0) {
Arrays.sort(files);
for (int i = 0; i < count; i++) {
if (!files[i].delete()) {
Slog.w(LOG_TAG, "Couldn't delete " + files[i] + ".");
}
}
}
}
/**
* Dumps the current device stats to a new file.
*/
private void dump() throws IOException {
OutputStream out = new FileOutputStream(
new File(BASE, String.valueOf(System.currentTimeMillis())));
try {
// Copy /proc/*/stat
for (File processDirectory : PROC.listFiles()) {
if (isProcessDirectory(processDirectory)) {
dump(new File(processDirectory, "stat"), out);
}
}
// Copy other files.
for (File file : PATHS) {
dump(file, out);
}
} finally {
closeQuietly(out);
}
}
/**
* Returns true if the given file represents a process directory.
*/
private static boolean isProcessDirectory(File file) {
try {
Integer.parseInt(file.getName());
return file.isDirectory();
} catch (NumberFormatException e) {
return false;
}
}
/**
* Copies from a file to an output stream.
*/
private void dump(File from, OutputStream out) throws IOException {
writeHeader(from, out);
FileInputStream in = null;
try {
in = new FileInputStream(from);
int count;
while ((count = in.read(buffer)) != -1) {
out.write(buffer, 0, count);
}
} finally {
closeQuietly(in);
}
}
/**
* Writes a header for the given file.
*/
private static void writeHeader(File file, OutputStream out)
throws IOException {
String header = "*** " + file.toString() + "\n";
out.write(header.getBytes());
}
/**
* Closes the given resource. Logs exceptions.
* @param closeable
*/
private static void closeQuietly(Closeable closeable) {
try {
if (closeable != null) {
closeable.close();
}
} catch (IOException e) {
Slog.w(LOG_TAG, e);
}
}
/**
* Pauses momentarily before we start the next dump.
*/
private void pause() {
try {
Thread.sleep(INTERVAL);
} catch (InterruptedException e) { /* ignore */ }
}
/**
* Stops dumping.
*/
private synchronized void stop() {
running = false;
}
/**
* Waits until someone starts us.
*/
private synchronized void waitForStart() {
while (!running) {
try {
wait();
} catch (InterruptedException e) { /* ignore */ }
}
}
/**
* Instructs the monitoring to start if it hasn't already.
*/
private synchronized void startMonitoring() {
if (!running) {
running = true;
notifyAll();
}
}
private static DeviceMonitor instance = new DeviceMonitor();
/**
* Starts monitoring if it hasn't started already.
*/
static void start() {
instance.startMonitoring();
}
}
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