/*
* Copyright (C) 2014 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 android.hardware.camera2.legacy;
import android.os.SystemClock;
import android.util.Log;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
/**
* GPU and CPU performance measurement for the legacy implementation.
*
* <p>Measures CPU and GPU processing duration for a set of operations, and dumps
* the results into a file.</p>
*
* <p>Rough usage:
* <pre>
* {@code
* <set up workload>
* <start long-running workload>
* mPerfMeasurement.startTimer();
* ...render a frame...
* mPerfMeasurement.stopTimer();
* <end workload>
* mPerfMeasurement.dumpPerformanceData("/sdcard/my_data.txt");
* }
* </pre>
* </p>
*
* <p>All calls to this object must be made within the same thread, and the same GL context.
* PerfMeasurement cannot be used outside of a GL context. The only exception is
* dumpPerformanceData, which can be called outside of a valid GL context.</p>
*/
class PerfMeasurement {
private static final String TAG = "PerfMeasurement";
public static final int DEFAULT_MAX_QUERIES = 3;
private final long mNativeContext;
private int mCompletedQueryCount = 0;
/**
* Values for completed measurements
*/
private ArrayList<Long> mCollectedGpuDurations = new ArrayList<>();
private ArrayList<Long> mCollectedCpuDurations = new ArrayList<>();
private ArrayList<Long> mCollectedTimestamps = new ArrayList<>();
/**
* Values for in-progress measurements (waiting for async GPU results)
*/
private Queue<Long> mTimestampQueue = new LinkedList<>();
private Queue<Long> mCpuDurationsQueue = new LinkedList<>();
private long mStartTimeNs;
/**
* The value returned by {@link #nativeGetNextGlDuration} if no new timing
* measurement is available since the last call.
*/
private static final long NO_DURATION_YET = -1l;
/**
* The value returned by {@link #nativeGetNextGlDuration} if timing failed for
* the next timing interval
*/
private static final long FAILED_TIMING = -2l;
/**
* Create a performance measurement object with a maximum of {@value #DEFAULT_MAX_QUERIES}
* in-progess queries.
*/
public PerfMeasurement() {
mNativeContext = nativeCreateContext(DEFAULT_MAX_QUERIES);
}
/**
* Create a performance measurement object with maxQueries as the maximum number of
* in-progress queries.
*
* @param maxQueries maximum in-progress queries, must be larger than 0.
* @throws IllegalArgumentException if maxQueries is less than 1.
*/
public PerfMeasurement(int maxQueries) {
if (maxQueries < 1) throw new IllegalArgumentException("maxQueries is less than 1");
mNativeContext = nativeCreateContext(maxQueries);
}
/**
* Returns true if the Gl timing methods will work, false otherwise.
*
* <p>Must be called within a valid GL context.</p>
*/
public static boolean isGlTimingSupported() {
return nativeQuerySupport();
}
/**
* Dump collected data to file, and clear the stored data.
*
* <p>
* Format is a simple csv-like text file with a header,
* followed by a 3-column list of values in nanoseconds:
* <pre>
* timestamp gpu_duration cpu_duration
* <long> <long> <long>
* <long> <long> <long>
* <long> <long> <long>
* ....
* </pre>
* </p>
*/
public void dumpPerformanceData(String path) {
try (BufferedWriter dump = new BufferedWriter(new FileWriter(path))) {
dump.write("timestamp gpu_duration cpu_duration\n");
for (int i = 0; i < mCollectedGpuDurations.size(); i++) {
dump.write(String.format("%d %d %d\n",
mCollectedTimestamps.get(i),
mCollectedGpuDurations.get(i),
mCollectedCpuDurations.get(i)));
}
mCollectedTimestamps.clear();
mCollectedGpuDurations.clear();
mCollectedCpuDurations.clear();
} catch (IOException e) {
Log.e(TAG, "Error writing data dump to " + path + ":" + e);
}
}
/**
* Start a GPU/CPU timing measurement.
*
* <p>Call before starting a rendering pass. Only one timing measurement can be active at once,
* so {@link #stopTimer} must be called before the next call to this method.</p>
*
* @throws IllegalStateException if the maximum number of queries are in progress already,
* or the method is called multiple times in a row, or there is
* a GPU error.
*/
public void startTimer() {
nativeStartGlTimer(mNativeContext);
mStartTimeNs = SystemClock.elapsedRealtimeNanos();
}
/**
* Finish a GPU/CPU timing measurement.
*
* <p>Call after finishing all the drawing for a rendering pass. Only one timing measurement can
* be active at once, so {@link #startTimer} must be called before the next call to this
* method.</p>
*
* @throws IllegalStateException if no GL timer is currently started, or there is a GPU
* error.
*/
public void stopTimer() {
// Complete CPU timing
long endTimeNs = SystemClock.elapsedRealtimeNanos();
mCpuDurationsQueue.add(endTimeNs - mStartTimeNs);
// Complete GL timing
nativeStopGlTimer(mNativeContext);
// Poll to see if GL timing results have arrived; if so
// store the results for a frame
long duration = getNextGlDuration();
if (duration > 0) {
mCollectedGpuDurations.add(duration);
mCollectedTimestamps.add(mTimestampQueue.isEmpty() ?
NO_DURATION_YET : mTimestampQueue.poll());
mCollectedCpuDurations.add(mCpuDurationsQueue.isEmpty() ?
NO_DURATION_YET : mCpuDurationsQueue.poll());
}
if (duration == FAILED_TIMING) {
// Discard timestamp and CPU measurement since GPU measurement failed
if (!mTimestampQueue.isEmpty()) {
mTimestampQueue.poll();
}
if (!mCpuDurationsQueue.isEmpty()) {
mCpuDurationsQueue.poll();
}
}
}
/**
* Add a timestamp to a timing measurement. These are queued up and matched to completed
* workload measurements as they become available.
*/
public void addTimestamp(long timestamp) {
mTimestampQueue.add(timestamp);
}
/**
* Get the next available GPU timing measurement.
*
* <p>Since the GPU works asynchronously, the results of a single start/stopGlTimer measurement
* will only be available some time after the {@link #stopTimer} call is made. Poll this method
* until the result becomes available. If multiple start/endTimer measurements are made in a
* row, the results will be available in FIFO order.</p>
*
* @return The measured duration of the GPU workload for the next pending query, or
* {@link #NO_DURATION_YET} if no queries are pending or the next pending query has not
* yet finished, or {@link #FAILED_TIMING} if the GPU was unable to complete the
* measurement.
*
* @throws IllegalStateException If there is a GPU error.
*
*/
private long getNextGlDuration() {
long duration = nativeGetNextGlDuration(mNativeContext);
if (duration > 0) {
mCompletedQueryCount++;
}
return duration;
}
/**
* Returns the number of measurements so far that returned a valid duration
* measurement.
*/
public int getCompletedQueryCount() {
return mCompletedQueryCount;
}
@Override
protected void finalize() {
nativeDeleteContext(mNativeContext);
}
/**
* Create a native performance measurement context.
*
* @param maxQueryCount maximum in-progress queries; must be >= 1.
*/
private static native long nativeCreateContext(int maxQueryCount);
/**
* Delete the native context.
*
* <p>Not safe to call more than once.</p>
*/
private static native void nativeDeleteContext(long contextHandle);
/**
* Query whether the relevant Gl extensions are available for Gl timing
*/
private static native boolean nativeQuerySupport();
/**
* Start a GL timing section.
*
* <p>All GL commands between this method and the next {@link #nativeEndGlTimer} will be
* included in the timing.</p>
*
* <p>Must be called from the same thread as calls to {@link #nativeEndGlTimer} and
* {@link #nativeGetNextGlDuration}.</p>
*
* @throws IllegalStateException if a GL error occurs or start is called repeatedly.
*/
protected static native void nativeStartGlTimer(long contextHandle);
/**
* Finish a GL timing section.
*
* <p>Some time after this call returns, the time the GPU took to
* execute all work submitted between the latest {@link #nativeStartGlTimer} and
* this call, will become available from calling {@link #nativeGetNextGlDuration}.</p>
*
* <p>Must be called from the same thread as calls to {@link #nativeStartGlTimer} and
* {@link #nativeGetNextGlDuration}.</p>
*
* @throws IllegalStateException if a GL error occurs or stop is called before start
*/
protected static native void nativeStopGlTimer(long contextHandle);
/**
* Get the next available GL duration measurement, in nanoseconds.
*
* <p>Must be called from the same thread as calls to {@link #nativeStartGlTimer} and
* {@link #nativeEndGlTimer}.</p>
*
* @return the next GL duration measurement, or {@link #NO_DURATION_YET} if
* no new measurement is available, or {@link #FAILED_TIMING} if timing
* failed for the next duration measurement.
* @throws IllegalStateException if a GL error occurs
*/
protected static native long nativeGetNextGlDuration(long contextHandle);
}
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