// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.base;
import android.os.Debug;
import android.os.Debug.MemoryInfo;
import android.util.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.LinkedList;
import java.util.List;
/**
* PerfTraceEvent can be used like TraceEvent, but is intended for
* performance measurement. By limiting the types of tracing we hope
* to minimize impact on measurement.
*
* All PerfTraceEvent events funnel into TraceEvent. When not doing
* performance measurements, they act the same. However,
* PerfTraceEvents can be enabled even when TraceEvent is not.
*
* Unlike TraceEvent, PerfTraceEvent data is sent to the system log,
* not to a trace file.
*
* Performance events need to have very specific names so we find
* the right ones. For example, we specify the name exactly in
* the @TracePerf annotation. Thus, unlike TraceEvent, we do not
* support an implicit trace name based on the callstack.
*/
public class PerfTraceEvent {
private static final int MAX_NAME_LENGTH = 40;
private static final String MEMORY_TRACE_NAME_SUFFIX = "_BZR_PSS";
private static File sOutputFile = null;
/** The event types understood by the perf trace scripts. */
private enum EventType {
START("S"),
FINISH("F"),
INSTANT("I");
// The string understood by the trace scripts.
private final String mTypeStr;
EventType(String typeStr) {
mTypeStr = typeStr;
}
@Override
public String toString() {
return mTypeStr;
}
}
private static boolean sEnabled = false;
private static boolean sTrackTiming = true;
private static boolean sTrackMemory = false;
// A list of performance trace event strings.
// Events are stored as a JSON dict much like TraceEvent.
// E.g. timestamp is in microseconds.
private static JSONArray sPerfTraceStrings;
// A filter for performance tracing. Only events that match a
// string in the list are saved. Presence of a filter does not
// necessarily mean perf tracing is enabled.
private static List<String> sFilter;
// Nanosecond start time of performance tracing.
private static long sBeginNanoTime;
/**
* Specifies what event names will be tracked.
*
* @param strings Event names we will record.
*/
public static synchronized void setFilter(List<String> strings) {
sFilter = new LinkedList<String>(strings);
}
/**
* Enable or disable perf tracing.
* Disabling of perf tracing will dump trace data to the system log.
*/
public static synchronized void setEnabled(boolean enabled) {
if (sEnabled == enabled) {
return;
}
if (enabled) {
sBeginNanoTime = System.nanoTime();
sPerfTraceStrings = new JSONArray();
} else {
dumpPerf();
sPerfTraceStrings = null;
sFilter = null;
}
sEnabled = enabled;
}
/**
* Enables memory tracking for all timing perf events tracked.
*
* <p>
* Only works when called in combination with {@link #setEnabled(boolean)}.
*
* <p>
* By enabling this feature, an additional perf event containing the memory usage will be
* logged whenever {@link #instant(String)}, {@link #begin(String)}, or {@link #end(String)}
* is called.
*
* @param enabled Whether to enable memory tracking for all perf events.
*/
public static synchronized void setMemoryTrackingEnabled(boolean enabled) {
sTrackMemory = enabled;
}
/**
* Enables timing tracking for all perf events tracked.
*
* <p>
* Only works when called in combination with {@link #setEnabled(boolean)}.
*
* <p>
* If this feature is enabled, whenever {@link #instant(String)}, {@link #begin(String)},
* or {@link #end(String)} is called the time since start of tracking will be logged.
*
* @param enabled Whether to enable timing tracking for all perf events.
*/
public static synchronized void setTimingTrackingEnabled(boolean enabled) {
sTrackTiming = enabled;
}
/**
* @return True if tracing is enabled, false otherwise.
* It is safe to call trace methods without checking if PerfTraceEvent
* is enabled.
*/
public static synchronized boolean enabled() {
return sEnabled;
}
/**
* Record an "instant" perf trace event. E.g. "screen update happened".
*/
public static synchronized void instant(String name) {
// Instant doesn't really need/take an event id, but this should be okay.
final long eventId = name.hashCode();
TraceEvent.instant(name);
if (sEnabled && matchesFilter(name)) {
savePerfString(name, eventId, EventType.INSTANT, false);
}
}
/**
* Record an "begin" perf trace event.
* Begin trace events should have a matching end event.
*/
public static synchronized void begin(String name) {
final long eventId = name.hashCode();
TraceEvent.startAsync(name, eventId);
if (sEnabled && matchesFilter(name)) {
// Done before calculating the starting perf data to ensure calculating the memory usage
// does not influence the timing data.
if (sTrackMemory) {
savePerfString(makeMemoryTraceNameFromTimingName(name), eventId, EventType.START,
true);
}
if (sTrackTiming) {
savePerfString(name, eventId, EventType.START, false);
}
}
}
/**
* Record an "end" perf trace event, to match a begin event. The
* time delta between begin and end is usually interesting to
* graph code.
*/
public static synchronized void end(String name) {
final long eventId = name.hashCode();
TraceEvent.finishAsync(name, eventId);
if (sEnabled && matchesFilter(name)) {
if (sTrackTiming) {
savePerfString(name, eventId, EventType.FINISH, false);
}
// Done after calculating the ending perf data to ensure calculating the memory usage
// does not influence the timing data.
if (sTrackMemory) {
savePerfString(makeMemoryTraceNameFromTimingName(name), eventId, EventType.FINISH,
true);
}
}
}
/**
* Record an "begin" memory trace event.
* Begin trace events should have a matching end event.
*/
public static synchronized void begin(String name, MemoryInfo memoryInfo) {
final long eventId = name.hashCode();
TraceEvent.startAsync(name, eventId);
if (sEnabled && matchesFilter(name)) {
// Done before calculating the starting perf data to ensure calculating the memory usage
// does not influence the timing data.
long timestampUs = (System.nanoTime() - sBeginNanoTime) / 1000;
savePerfString(makeMemoryTraceNameFromTimingName(name), eventId, EventType.START,
timestampUs, memoryInfo);
if (sTrackTiming) {
savePerfString(name, eventId, EventType.START, false);
}
}
}
/**
* Record an "end" memory trace event, to match a begin event. The
* memory usage delta between begin and end is usually interesting to
* graph code.
*/
public static synchronized void end(String name, MemoryInfo memoryInfo) {
final long eventId = name.hashCode();
TraceEvent.finishAsync(name, eventId);
if (sEnabled && matchesFilter(name)) {
if (sTrackTiming) {
savePerfString(name, eventId, EventType.FINISH, false);
}
// Done after calculating the instant perf data to ensure calculating the memory usage
// does not influence the timing data.
long timestampUs = (System.nanoTime() - sBeginNanoTime) / 1000;
savePerfString(makeMemoryTraceNameFromTimingName(name), eventId, EventType.FINISH,
timestampUs, memoryInfo);
}
}
/**
* Determine if we are interested in this trace event.
* @return True if the name matches the allowed filter; else false.
*/
private static boolean matchesFilter(String name) {
return sFilter != null ? sFilter.contains(name) : false;
}
/**
* Save a perf trace event as a JSON dict. The format mirrors a TraceEvent dict.
*
* @param name The trace data
* @param id The id of the event
* @param type the type of trace event (I, S, F)
* @param includeMemory Whether to include current browser process memory usage in the trace.
*/
private static void savePerfString(String name, long id, EventType type,
boolean includeMemory) {
long timestampUs = (System.nanoTime() - sBeginNanoTime) / 1000;
MemoryInfo memInfo = null;
if (includeMemory) {
memInfo = new MemoryInfo();
Debug.getMemoryInfo(memInfo);
}
savePerfString(name, id, type, timestampUs, memInfo);
}
/**
* Save a perf trace event as a JSON dict. The format mirrors a TraceEvent dict.
*
* @param name The trace data
* @param id The id of the event
* @param type the type of trace event (I, S, F)
* @param timestampUs The time stamp at which this event was recorded
* @param memoryInfo Memory details to be included in this perf string, null if
* no memory details are to be included.
*/
private static void savePerfString(String name, long id, EventType type, long timestampUs,
MemoryInfo memoryInfo) {
try {
JSONObject traceObj = new JSONObject();
traceObj.put("cat", "Java");
traceObj.put("ts", timestampUs);
traceObj.put("ph", type);
traceObj.put("name", name);
traceObj.put("id", id);
if (memoryInfo != null) {
int pss = memoryInfo.nativePss + memoryInfo.dalvikPss + memoryInfo.otherPss;
traceObj.put("mem", pss);
}
sPerfTraceStrings.put(traceObj);
} catch (JSONException e) {
throw new RuntimeException(e);
}
}
/**
* Generating a trace name for tracking memory based on the timing name passed in.
*
* @param name The timing name to use as a base for the memory perf name.
* @return The memory perf name to use.
*/
public static String makeMemoryTraceNameFromTimingName(String name) {
return makeSafeTraceName(name, MEMORY_TRACE_NAME_SUFFIX);
}
/**
* Builds a name to be used in the perf trace framework. The framework has length requirements
* for names, so this ensures the generated name does not exceed the maximum (trimming the
* base name if necessary).
*
* @param baseName The base name to use when generating the name.
* @param suffix The required suffix to be appended to the name.
* @return A name that is safe for the perf trace framework.
*/
public static String makeSafeTraceName(String baseName, String suffix) {
int suffixLength = suffix.length();
if (baseName.length() + suffixLength > MAX_NAME_LENGTH) {
baseName = baseName.substring(0, MAX_NAME_LENGTH - suffixLength);
}
return baseName + suffix;
}
/**
* Sets a file to dump the results to. If {@code file} is {@code null}, it will be dumped
* to STDOUT, otherwise the JSON performance data will be appended to {@code file}. This should
* be called before the performance run starts. When {@link #setEnabled(boolean)} is called
* with {@code false}, the perf data will be dumped.
*
* @param file Which file to append the performance data to. If {@code null}, the performance
* data will be sent to STDOUT.
*/
public static synchronized void setOutputFile(File file) {
sOutputFile = file;
}
/**
* Dump all performance data we have saved up to the log.
* Output as JSON for parsing convenience.
*/
private static void dumpPerf() {
String json = sPerfTraceStrings.toString();
if (sOutputFile == null) {
System.out.println(json);
} else {
try {
PrintStream stream = new PrintStream(new FileOutputStream(sOutputFile, true));
try {
stream.print(json);
} finally {
try {
stream.close();
} catch (Exception ex) {
Log.e("PerfTraceEvent", "Unable to close perf trace output file.");
}
}
} catch (FileNotFoundException ex) {
Log.e("PerfTraceEvent", "Unable to dump perf trace data to output file.");
}
}
}
}