Reduce number of Fence syscalls made.
This patch saves 6 or more Fence syscalls per frame.
* Timelines are updated just before adding a new fence
since the newly added fence is unlikely to have signaled.
* Layer::latch uses a FenceTime now, so the signal time is
automatically shared with other owners of the FenceTime.
* DispSync uses FenceTime now, only using cached values of
the signal time that have been populated by a Timeline.
Test: SurfaceFlinger boots and dumps still work.
Change-Id: Ie0cfc1af2aca143dd8d5f08f08dbe1e597376f2f
diff --git a/services/surfaceflinger/DispSync.cpp b/services/surfaceflinger/DispSync.cpp
index bd9b8aa..ac8aa04 100644
--- a/services/surfaceflinger/DispSync.cpp
+++ b/services/surfaceflinger/DispSync.cpp
@@ -30,7 +30,7 @@
#include <utils/Trace.h>
#include <utils/Vector.h>
-#include <ui/Fence.h>
+#include <ui/FenceTime.h>
#include "DispSync.h"
#include "SurfaceFlinger.h"
@@ -419,25 +419,13 @@
resetErrorLocked();
}
-bool DispSync::addPresentFence(const sp<Fence>& fence) {
+bool DispSync::addPresentFence(const std::shared_ptr<FenceTime>& fenceTime) {
Mutex::Autolock lock(mMutex);
- mPresentFences[mPresentSampleOffset] = fence;
- mPresentTimes[mPresentSampleOffset] = 0;
+ mPresentFences[mPresentSampleOffset] = fenceTime;
mPresentSampleOffset = (mPresentSampleOffset + 1) % NUM_PRESENT_SAMPLES;
mNumResyncSamplesSincePresent = 0;
- for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
- const sp<Fence>& f(mPresentFences[i]);
- if (f != NULL) {
- nsecs_t t = f->getSignalTime();
- if (t < INT64_MAX) {
- mPresentFences[i].clear();
- mPresentTimes[i] = t + mPresentTimeOffset;
- }
- }
- }
-
updateErrorLocked();
return !mModelUpdated || mError > kErrorThreshold;
@@ -602,21 +590,39 @@
nsecs_t sqErrSum = 0;
for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
- nsecs_t sample = mPresentTimes[i] - mReferenceTime;
- if (sample > mPhase) {
- nsecs_t sampleErr = (sample - mPhase) % period;
- if (sampleErr > period / 2) {
- sampleErr -= period;
- }
- sqErrSum += sampleErr * sampleErr;
- numErrSamples++;
+ // Only check for the cached value of signal time to avoid unecessary
+ // syscalls. It is the responsibility of the DispSync owner to
+ // call getSignalTime() periodically so the cache is updated when the
+ // fence signals.
+ nsecs_t time = mPresentFences[i]->getCachedSignalTime();
+ if (time == Fence::SIGNAL_TIME_PENDING ||
+ time == Fence::SIGNAL_TIME_INVALID) {
+ continue;
}
+
+ nsecs_t sample = time - mReferenceTime;
+ if (sample <= mPhase) {
+ continue;
+ }
+
+ nsecs_t sampleErr = (sample - mPhase) % period;
+ if (sampleErr > period / 2) {
+ sampleErr -= period;
+ }
+ sqErrSum += sampleErr * sampleErr;
+ numErrSamples++;
}
if (numErrSamples > 0) {
mError = sqErrSum / numErrSamples;
+ mZeroErrSamplesCount = 0;
} else {
mError = 0;
+ // Use mod ACCEPTABLE_ZERO_ERR_SAMPLES_COUNT to avoid log spam.
+ mZeroErrSamplesCount++;
+ ALOGE_IF(
+ (mZeroErrSamplesCount % ACCEPTABLE_ZERO_ERR_SAMPLES_COUNT) == 0,
+ "No present times for model error.");
}
if (kTraceDetailedInfo) {
@@ -627,9 +633,9 @@
void DispSync::resetErrorLocked() {
mPresentSampleOffset = 0;
mError = 0;
+ mZeroErrSamplesCount = 0;
for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
- mPresentFences[i].clear();
- mPresentTimes[i] = 0;
+ mPresentFences[i] = FenceTime::NO_FENCE;
}
}
@@ -668,19 +674,19 @@
previous = sampleTime;
}
- result.appendFormat("mPresentFences / mPresentTimes [%d]:\n",
+ result.appendFormat("mPresentFences [%d]:\n",
NUM_PRESENT_SAMPLES);
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
- previous = 0;
+ previous = Fence::SIGNAL_TIME_INVALID;
for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
size_t idx = (i + mPresentSampleOffset) % NUM_PRESENT_SAMPLES;
- bool signaled = mPresentFences[idx] == NULL;
- nsecs_t presentTime = mPresentTimes[idx];
- if (!signaled) {
+ nsecs_t presentTime = mPresentFences[idx]->getSignalTime();
+ if (presentTime == Fence::SIGNAL_TIME_PENDING) {
result.appendFormat(" [unsignaled fence]\n");
- } else if (presentTime == 0) {
- result.appendFormat(" 0\n");
- } else if (previous == 0) {
+ } else if(presentTime == Fence::SIGNAL_TIME_INVALID) {
+ result.appendFormat(" [invalid fence]\n");
+ } else if (previous == Fence::SIGNAL_TIME_PENDING ||
+ previous == Fence::SIGNAL_TIME_INVALID) {
result.appendFormat(" %" PRId64 " (%.3f ms ago)\n", presentTime,
(now - presentTime) / 1000000.0);
} else {