libs/hwui/JankTracker.cpp - platform/frameworks/base - Gitiles

 /*
  * Copyright (C) 2015 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.
  */
 #include "JankTracker.h"

 #include "Properties.h"

 #include <algorithm>
 #include <cutils/ashmem.h>
 #include <cutils/log.h>
 #include <cstdio>
 #include <errno.h>
 #include <inttypes.h>
 #include <limits>
 #include <cmath>
 #include <sys/mman.h>

 namespace android {
 namespace uirenderer {

 static const char* JANK_TYPE_NAMES[] = {
         "Missed Vsync",
         "High input latency",
         "Slow UI thread",
         "Slow bitmap uploads",
         "Slow issue draw commands",
 };

 struct Comparison {
     FrameInfoIndex start;
     FrameInfoIndex end;
 };

 static const Comparison COMPARISONS[] = {
         {FrameInfoIndex::IntendedVsync, FrameInfoIndex::Vsync},
         {FrameInfoIndex::OldestInputEvent, FrameInfoIndex::Vsync},
         {FrameInfoIndex::Vsync, FrameInfoIndex::SyncStart},
         {FrameInfoIndex::SyncStart, FrameInfoIndex::IssueDrawCommandsStart},
         {FrameInfoIndex::IssueDrawCommandsStart, FrameInfoIndex::FrameCompleted},
 };

 // If the event exceeds 10 seconds throw it away, this isn't a jank event
 // it's an ANR and will be handled as such
 static const int64_t IGNORE_EXCEEDING = seconds_to_nanoseconds(10);

 /*
  * We don't track direct-drawing via Surface:lockHardwareCanvas()
  * for now
  *
  * TODO: kSurfaceCanvas can negatively impact other drawing by using up
  * time on the RenderThread, figure out how to attribute that as a jank-causer
  */
 static const int64_t EXEMPT_FRAMES_FLAGS = FrameInfoFlags::SurfaceCanvas;

 // The bucketing algorithm controls so to speak
 // If a frame is <= to this it goes in bucket 0
 static const uint32_t kBucketMinThreshold = 5;
 // If a frame is > this, start counting in increments of 2ms
 static const uint32_t kBucket2msIntervals = 32;
 // If a frame is > this, start counting in increments of 4ms
 static const uint32_t kBucket4msIntervals = 48;

 // For testing purposes to try and eliminate test infra overhead we will
 // consider any unknown delay of frame start as part of the test infrastructure
 // and filter it out of the frame profile data
 static FrameInfoIndex sFrameStart = FrameInfoIndex::IntendedVsync;

 // The interval of the slow frame histogram
 static const uint32_t kSlowFrameBucketIntervalMs = 50;
 // The start point of the slow frame bucket in ms
 static const uint32_t kSlowFrameBucketStartMs = 150;

 // This will be called every frame, performance sensitive
 // Uses bit twiddling to avoid branching while achieving the packing desired
 static uint32_t frameCountIndexForFrameTime(nsecs_t frameTime) {
     uint32_t index = static_cast<uint32_t>(ns2ms(frameTime));
     // If index > kBucketMinThreshold mask will be 0xFFFFFFFF as a result
     // of negating 1 (twos compliment, yaay) else mask will be 0
     uint32_t mask = -(index > kBucketMinThreshold);
     // If index > threshold, this will essentially perform:
     // amountAboveThreshold = index - threshold;
     // index = threshold + (amountAboveThreshold / 2)
     // However if index is <= this will do nothing. It will underflow, do
     // a right shift by 0 (no-op), then overflow back to the original value
     index = ((index - kBucket4msIntervals) >> (index > kBucket4msIntervals))
             + kBucket4msIntervals;
     index = ((index - kBucket2msIntervals) >> (index > kBucket2msIntervals))
             + kBucket2msIntervals;
     // If index was < minThreshold at the start of all this it's going to
     // be a pretty garbage value right now. However, mask is 0 so we'll end
     // up with the desired result of 0.
     index = (index - kBucketMinThreshold) & mask;
     return index;
 }

 // Only called when dumping stats, less performance sensitive
 static uint32_t frameTimeForFrameCountIndex(uint32_t index) {
     index = index + kBucketMinThreshold;
     if (index > kBucket2msIntervals) {
         index += (index - kBucket2msIntervals);
     }
     if (index > kBucket4msIntervals) {
         // This works because it was already doubled by the above if
         // 1 is added to shift slightly more towards the middle of the bucket
         index += (index - kBucket4msIntervals) + 1;
     }
     return index;
 }

 JankTracker::JankTracker(nsecs_t frameIntervalNanos) {
     // By default this will use malloc memory. It may be moved later to ashmem
     // if there is shared space for it and a request comes in to do that.
     mData = new ProfileData;
     reset();
     setFrameInterval(frameIntervalNanos);
 }

 JankTracker::~JankTracker() {
     freeData();
 }

 void JankTracker::freeData() {
     if (mIsMapped) {
         munmap(mData, sizeof(ProfileData));
     } else {
         delete mData;
     }
     mIsMapped = false;
     mData = nullptr;
 }

 void JankTracker::switchStorageToAshmem(int ashmemfd) {
     int regionSize = ashmem_get_size_region(ashmemfd);
     if (regionSize < static_cast<int>(sizeof(ProfileData))) {
         ALOGW("Ashmem region is too small! Received %d, required %u",
                 regionSize, static_cast<unsigned int>(sizeof(ProfileData)));
         return;
     }
     ProfileData* newData = reinterpret_cast<ProfileData*>(
             mmap(NULL, sizeof(ProfileData), PROT_READ | PROT_WRITE,
             MAP_SHARED, ashmemfd, 0));
     if (newData == MAP_FAILED) {
         int err = errno;
         ALOGW("Failed to move profile data to ashmem fd %d, error = %d",
                 ashmemfd, err);
         return;
     }

     // The new buffer may have historical data that we want to build on top of
     // But let's make sure we don't overflow Just In Case
     uint32_t divider = 0;
     if (newData->totalFrameCount > (1 << 24)) {
         divider = 4;
     }
     for (size_t i = 0; i < mData->jankTypeCounts.size(); i++) {
         newData->jankTypeCounts[i] >>= divider;
         newData->jankTypeCounts[i] += mData->jankTypeCounts[i];
     }
     for (size_t i = 0; i < mData->frameCounts.size(); i++) {
         newData->frameCounts[i] >>= divider;
         newData->frameCounts[i] += mData->frameCounts[i];
     }
     newData->jankFrameCount >>= divider;
     newData->jankFrameCount += mData->jankFrameCount;
     newData->totalFrameCount >>= divider;
     newData->totalFrameCount += mData->totalFrameCount;
     if (newData->statStartTime > mData->statStartTime
             || newData->statStartTime == 0) {
         newData->statStartTime = mData->statStartTime;
     }

     freeData();
     mData = newData;
     mIsMapped = true;
 }

 void JankTracker::setFrameInterval(nsecs_t frameInterval) {
     mFrameInterval = frameInterval;
     mThresholds[kMissedVsync] = 1;
     /*
      * Due to interpolation and sample rate differences between the touch
      * panel and the display (example, 85hz touch panel driving a 60hz display)
      * we call high latency 1.5 * frameinterval
      *
      * NOTE: Be careful when tuning this! A theoretical 1,000hz touch panel
      * on a 60hz display will show kOldestInputEvent - kIntendedVsync of being 15ms
      * Thus this must always be larger than frameInterval, or it will fail
      */
     mThresholds[kHighInputLatency] = static_cast<int64_t>(1.5 * frameInterval);

     // Note that these do not add up to 1. This is intentional. It's to deal
     // with variance in values, and should be sort of an upper-bound on what
     // is reasonable to expect.
     mThresholds[kSlowUI] = static_cast<int64_t>(.5 * frameInterval);
     mThresholds[kSlowSync] = static_cast<int64_t>(.2 * frameInterval);
     mThresholds[kSlowRT] = static_cast<int64_t>(.75 * frameInterval);

 }

 void JankTracker::addFrame(const FrameInfo& frame) {
     mData->totalFrameCount++;
     // Fast-path for jank-free frames
     int64_t totalDuration = frame.duration(sFrameStart, FrameInfoIndex::FrameCompleted);
     uint32_t framebucket = frameCountIndexForFrameTime(totalDuration);
     // Keep the fast path as fast as possible.
     if (CC_LIKELY(totalDuration < mFrameInterval)) {
         mData->frameCounts[framebucket]++;
         return;
     }

     // Only things like Surface.lockHardwareCanvas() are exempt from tracking
     if (frame[FrameInfoIndex::Flags] & EXEMPT_FRAMES_FLAGS) {
         return;
     }

     if (framebucket <= mData->frameCounts.size()) {
         mData->frameCounts[framebucket]++;
     } else {
         framebucket = (ns2ms(totalDuration) - kSlowFrameBucketStartMs)
                 / kSlowFrameBucketIntervalMs;
         framebucket = std::min(framebucket,
                 static_cast<uint32_t>(mData->slowFrameCounts.size() - 1));
         framebucket = std::max(framebucket, 0u);
         mData->slowFrameCounts[framebucket]++;
     }

     mData->jankFrameCount++;

     for (int i = 0; i < NUM_BUCKETS; i++) {
         int64_t delta = frame.duration(COMPARISONS[i].start, COMPARISONS[i].end);
         if (delta >= mThresholds[i] && delta < IGNORE_EXCEEDING) {
             mData->jankTypeCounts[i]++;
         }
     }
 }

 void JankTracker::dumpBuffer(const void* buffer, size_t bufsize, int fd) {
     if (bufsize < sizeof(ProfileData)) {
         return;
     }
     const ProfileData* data = reinterpret_cast<const ProfileData*>(buffer);
     dumpData(data, fd);
 }

 void JankTracker::dumpData(const ProfileData* data, int fd) {
     if (sFrameStart != FrameInfoIndex::IntendedVsync) {
         dprintf(fd, "\nNote: Data has been filtered!");
     }
     dprintf(fd, "\nStats since: %" PRIu64 "ns", data->statStartTime);
     dprintf(fd, "\nTotal frames rendered: %u", data->totalFrameCount);
     dprintf(fd, "\nJanky frames: %u (%.2f%%)", data->jankFrameCount,
             (float) data->jankFrameCount / (float) data->totalFrameCount * 100.0f);
     dprintf(fd, "\n50th percentile: %ums", findPercentile(data, 50));
     dprintf(fd, "\n90th percentile: %ums", findPercentile(data, 90));
     dprintf(fd, "\n95th percentile: %ums", findPercentile(data, 95));
     dprintf(fd, "\n99th percentile: %ums", findPercentile(data, 99));
     for (int i = 0; i < NUM_BUCKETS; i++) {
         dprintf(fd, "\nNumber %s: %u", JANK_TYPE_NAMES[i], data->jankTypeCounts[i]);
     }
     dprintf(fd, "\nHISTOGRAM:");
     for (size_t i = 0; i < data->frameCounts.size(); i++) {
         dprintf(fd, " %ums=%u", frameTimeForFrameCountIndex(i),
                 data->frameCounts[i]);
     }
     for (size_t i = 0; i < data->slowFrameCounts.size(); i++) {
         dprintf(fd, " %zums=%u", (i * kSlowFrameBucketIntervalMs) + kSlowFrameBucketStartMs,
                 data->slowFrameCounts[i]);
     }
     dprintf(fd, "\n");
 }

 void JankTracker::reset() {
     mData->jankTypeCounts.fill(0);
     mData->frameCounts.fill(0);
     mData->slowFrameCounts.fill(0);
     mData->totalFrameCount = 0;
     mData->jankFrameCount = 0;
     mData->statStartTime = systemTime(CLOCK_MONOTONIC);
     sFrameStart = Properties::filterOutTestOverhead
             ? FrameInfoIndex::HandleInputStart
             : FrameInfoIndex::IntendedVsync;
 }

 uint32_t JankTracker::findPercentile(const ProfileData* data, int percentile) {
     int pos = percentile * data->totalFrameCount / 100;
     int remaining = data->totalFrameCount - pos;
     for (int i = data->slowFrameCounts.size() - 1; i >= 0; i--) {
         remaining -= data->slowFrameCounts[i];
         if (remaining <= 0) {
             return (i * kSlowFrameBucketIntervalMs) + kSlowFrameBucketStartMs;
         }
     }
     for (int i = data->frameCounts.size() - 1; i >= 0; i--) {
         remaining -= data->frameCounts[i];
         if (remaining <= 0) {
             return frameTimeForFrameCountIndex(i);
         }
     }
     return 0;
 }

 } /* namespace uirenderer */
 } /* namespace android */
	/*
	* Copyright (C) 2015 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.
	*/
	#include "JankTracker.h"

	#include "Properties.h"

	#include <algorithm>
	#include <cutils/ashmem.h>
	#include <cutils/log.h>
	#include <cstdio>
	#include <errno.h>
	#include <inttypes.h>
	#include <limits>
	#include <cmath>
	#include <sys/mman.h>

	namespace android {
	namespace uirenderer {

	static const char* JANK_TYPE_NAMES[] = {
	"Missed Vsync",
	"High input latency",
	"Slow UI thread",
	"Slow bitmap uploads",
	"Slow issue draw commands",
	};

	struct Comparison {
	FrameInfoIndex start;
	FrameInfoIndex end;
	};

	static const Comparison COMPARISONS[] = {
	{FrameInfoIndex::IntendedVsync, FrameInfoIndex::Vsync},
	{FrameInfoIndex::OldestInputEvent, FrameInfoIndex::Vsync},
	{FrameInfoIndex::Vsync, FrameInfoIndex::SyncStart},
	{FrameInfoIndex::SyncStart, FrameInfoIndex::IssueDrawCommandsStart},
	{FrameInfoIndex::IssueDrawCommandsStart, FrameInfoIndex::FrameCompleted},
	};

	// If the event exceeds 10 seconds throw it away, this isn't a jank event
	// it's an ANR and will be handled as such
	static const int64_t IGNORE_EXCEEDING = seconds_to_nanoseconds(10);

	/*
	* We don't track direct-drawing via Surface:lockHardwareCanvas()
	* for now
	*
	* TODO: kSurfaceCanvas can negatively impact other drawing by using up
	* time on the RenderThread, figure out how to attribute that as a jank-causer
	*/
	static const int64_t EXEMPT_FRAMES_FLAGS = FrameInfoFlags::SurfaceCanvas;

	// The bucketing algorithm controls so to speak
	// If a frame is <= to this it goes in bucket 0
	static const uint32_t kBucketMinThreshold = 5;
	// If a frame is > this, start counting in increments of 2ms
	static const uint32_t kBucket2msIntervals = 32;
	// If a frame is > this, start counting in increments of 4ms
	static const uint32_t kBucket4msIntervals = 48;

	// For testing purposes to try and eliminate test infra overhead we will
	// consider any unknown delay of frame start as part of the test infrastructure
	// and filter it out of the frame profile data
	static FrameInfoIndex sFrameStart = FrameInfoIndex::IntendedVsync;

	// The interval of the slow frame histogram
	static const uint32_t kSlowFrameBucketIntervalMs = 50;
	// The start point of the slow frame bucket in ms
	static const uint32_t kSlowFrameBucketStartMs = 150;

	// This will be called every frame, performance sensitive
	// Uses bit twiddling to avoid branching while achieving the packing desired
	static uint32_t frameCountIndexForFrameTime(nsecs_t frameTime) {
	uint32_t index = static_cast<uint32_t>(ns2ms(frameTime));
	// If index > kBucketMinThreshold mask will be 0xFFFFFFFF as a result
	// of negating 1 (twos compliment, yaay) else mask will be 0
	uint32_t mask = -(index > kBucketMinThreshold);
	// If index > threshold, this will essentially perform:
	// amountAboveThreshold = index - threshold;
	// index = threshold + (amountAboveThreshold / 2)
	// However if index is <= this will do nothing. It will underflow, do
	// a right shift by 0 (no-op), then overflow back to the original value
	index = ((index - kBucket4msIntervals) >> (index > kBucket4msIntervals))
	+ kBucket4msIntervals;
	index = ((index - kBucket2msIntervals) >> (index > kBucket2msIntervals))
	+ kBucket2msIntervals;
	// If index was < minThreshold at the start of all this it's going to
	// be a pretty garbage value right now. However, mask is 0 so we'll end
	// up with the desired result of 0.
	index = (index - kBucketMinThreshold) & mask;
	return index;
	}

	// Only called when dumping stats, less performance sensitive
	static uint32_t frameTimeForFrameCountIndex(uint32_t index) {
	index = index + kBucketMinThreshold;
	if (index > kBucket2msIntervals) {
	index += (index - kBucket2msIntervals);
	}
	if (index > kBucket4msIntervals) {
	// This works because it was already doubled by the above if
	// 1 is added to shift slightly more towards the middle of the bucket
	index += (index - kBucket4msIntervals) + 1;
	}
	return index;
	}

	JankTracker::JankTracker(nsecs_t frameIntervalNanos) {
	// By default this will use malloc memory. It may be moved later to ashmem
	// if there is shared space for it and a request comes in to do that.
	mData = new ProfileData;
	reset();
	setFrameInterval(frameIntervalNanos);
	}

	JankTracker::~JankTracker() {
	freeData();
	}

	void JankTracker::freeData() {
	if (mIsMapped) {
	munmap(mData, sizeof(ProfileData));
	} else {
	delete mData;
	}
	mIsMapped = false;
	mData = nullptr;
	}

	void JankTracker::switchStorageToAshmem(int ashmemfd) {
	int regionSize = ashmem_get_size_region(ashmemfd);
	if (regionSize < static_cast<int>(sizeof(ProfileData))) {
	ALOGW("Ashmem region is too small! Received %d, required %u",
	regionSize, static_cast<unsigned int>(sizeof(ProfileData)));
	return;
	}
	ProfileData* newData = reinterpret_cast<ProfileData*>(
	mmap(NULL, sizeof(ProfileData), PROT_READ \| PROT_WRITE,
	MAP_SHARED, ashmemfd, 0));
	if (newData == MAP_FAILED) {
	int err = errno;
	ALOGW("Failed to move profile data to ashmem fd %d, error = %d",
	ashmemfd, err);
	return;
	}

	// The new buffer may have historical data that we want to build on top of
	// But let's make sure we don't overflow Just In Case
	uint32_t divider = 0;
	if (newData->totalFrameCount > (1 << 24)) {
	divider = 4;
	}
	for (size_t i = 0; i < mData->jankTypeCounts.size(); i++) {
	newData->jankTypeCounts[i] >>= divider;
	newData->jankTypeCounts[i] += mData->jankTypeCounts[i];
	}
	for (size_t i = 0; i < mData->frameCounts.size(); i++) {
	newData->frameCounts[i] >>= divider;
	newData->frameCounts[i] += mData->frameCounts[i];
	}
	newData->jankFrameCount >>= divider;
	newData->jankFrameCount += mData->jankFrameCount;
	newData->totalFrameCount >>= divider;
	newData->totalFrameCount += mData->totalFrameCount;
	if (newData->statStartTime > mData->statStartTime
	\|\| newData->statStartTime == 0) {
	newData->statStartTime = mData->statStartTime;
	}

	freeData();
	mData = newData;
	mIsMapped = true;
	}

	void JankTracker::setFrameInterval(nsecs_t frameInterval) {
	mFrameInterval = frameInterval;
	mThresholds[kMissedVsync] = 1;
	/*
	* Due to interpolation and sample rate differences between the touch
	* panel and the display (example, 85hz touch panel driving a 60hz display)
	* we call high latency 1.5 * frameinterval
	*
	* NOTE: Be careful when tuning this! A theoretical 1,000hz touch panel
	* on a 60hz display will show kOldestInputEvent - kIntendedVsync of being 15ms
	* Thus this must always be larger than frameInterval, or it will fail
	*/
	mThresholds[kHighInputLatency] = static_cast<int64_t>(1.5 * frameInterval);

	// Note that these do not add up to 1. This is intentional. It's to deal
	// with variance in values, and should be sort of an upper-bound on what
	// is reasonable to expect.
	mThresholds[kSlowUI] = static_cast<int64_t>(.5 * frameInterval);
	mThresholds[kSlowSync] = static_cast<int64_t>(.2 * frameInterval);
	mThresholds[kSlowRT] = static_cast<int64_t>(.75 * frameInterval);

	}

	void JankTracker::addFrame(const FrameInfo& frame) {
	mData->totalFrameCount++;
	// Fast-path for jank-free frames
	int64_t totalDuration = frame.duration(sFrameStart, FrameInfoIndex::FrameCompleted);
	uint32_t framebucket = frameCountIndexForFrameTime(totalDuration);
	// Keep the fast path as fast as possible.
	if (CC_LIKELY(totalDuration < mFrameInterval)) {
	mData->frameCounts[framebucket]++;
	return;
	}

	// Only things like Surface.lockHardwareCanvas() are exempt from tracking
	if (frame[FrameInfoIndex::Flags] & EXEMPT_FRAMES_FLAGS) {
	return;
	}

	if (framebucket <= mData->frameCounts.size()) {
	mData->frameCounts[framebucket]++;
	} else {
	framebucket = (ns2ms(totalDuration) - kSlowFrameBucketStartMs)
	/ kSlowFrameBucketIntervalMs;
	framebucket = std::min(framebucket,
	static_cast<uint32_t>(mData->slowFrameCounts.size() - 1));
	framebucket = std::max(framebucket, 0u);
	mData->slowFrameCounts[framebucket]++;
	}

	mData->jankFrameCount++;

	for (int i = 0; i < NUM_BUCKETS; i++) {
	int64_t delta = frame.duration(COMPARISONS[i].start, COMPARISONS[i].end);
	if (delta >= mThresholds[i] && delta < IGNORE_EXCEEDING) {
	mData->jankTypeCounts[i]++;
	}
	}
	}

	void JankTracker::dumpBuffer(const void* buffer, size_t bufsize, int fd) {
	if (bufsize < sizeof(ProfileData)) {
	return;
	}
	const ProfileData* data = reinterpret_cast<const ProfileData*>(buffer);
	dumpData(data, fd);
	}

	void JankTracker::dumpData(const ProfileData* data, int fd) {
	if (sFrameStart != FrameInfoIndex::IntendedVsync) {
	dprintf(fd, "\nNote: Data has been filtered!");
	}
	dprintf(fd, "\nStats since: %" PRIu64 "ns", data->statStartTime);
	dprintf(fd, "\nTotal frames rendered: %u", data->totalFrameCount);
	dprintf(fd, "\nJanky frames: %u (%.2f%%)", data->jankFrameCount,
	(float) data->jankFrameCount / (float) data->totalFrameCount * 100.0f);
	dprintf(fd, "\n50th percentile: %ums", findPercentile(data, 50));
	dprintf(fd, "\n90th percentile: %ums", findPercentile(data, 90));
	dprintf(fd, "\n95th percentile: %ums", findPercentile(data, 95));
	dprintf(fd, "\n99th percentile: %ums", findPercentile(data, 99));
	for (int i = 0; i < NUM_BUCKETS; i++) {
	dprintf(fd, "\nNumber %s: %u", JANK_TYPE_NAMES[i], data->jankTypeCounts[i]);
	}
	dprintf(fd, "\nHISTOGRAM:");
	for (size_t i = 0; i < data->frameCounts.size(); i++) {
	dprintf(fd, " %ums=%u", frameTimeForFrameCountIndex(i),
	data->frameCounts[i]);
	}
	for (size_t i = 0; i < data->slowFrameCounts.size(); i++) {
	dprintf(fd, " %zums=%u", (i * kSlowFrameBucketIntervalMs) + kSlowFrameBucketStartMs,
	data->slowFrameCounts[i]);
	}
	dprintf(fd, "\n");
	}

	void JankTracker::reset() {
	mData->jankTypeCounts.fill(0);
	mData->frameCounts.fill(0);
	mData->slowFrameCounts.fill(0);
	mData->totalFrameCount = 0;
	mData->jankFrameCount = 0;
	mData->statStartTime = systemTime(CLOCK_MONOTONIC);
	sFrameStart = Properties::filterOutTestOverhead
	? FrameInfoIndex::HandleInputStart
	: FrameInfoIndex::IntendedVsync;
	}

	uint32_t JankTracker::findPercentile(const ProfileData* data, int percentile) {
	int pos = percentile * data->totalFrameCount / 100;
	int remaining = data->totalFrameCount - pos;
	for (int i = data->slowFrameCounts.size() - 1; i >= 0; i--) {
	remaining -= data->slowFrameCounts[i];
	if (remaining <= 0) {
	return (i * kSlowFrameBucketIntervalMs) + kSlowFrameBucketStartMs;
	}
	}
	for (int i = data->frameCounts.size() - 1; i >= 0; i--) {
	remaining -= data->frameCounts[i];
	if (remaining <= 0) {
	return frameTimeForFrameCountIndex(i);
	}
	}
	return 0;
	}

	} /* namespace uirenderer */
	} /* namespace android */