commit 932f008485dbb6fb452c8616abd7586f914f72ce
author Dan Stoza <stoza@google.com> Wed May 31 13:50:16 2017 -0700
committer Dan Stoza <stoza@google.com> Wed May 31 14:07:50 2017 -0700
tree 80e34a4090291d4ddbd9e9b3411f29e5b498e1d2
parent 1e4088fc68d88726bac0349b674ea557a63e0f27

libgui: Add Surface::getLastDequeueStartTime

Adds the getLastDequeueStartTime method, which allows the caller to
determine whether the last dequeueBuffer call fell into a given time
window.

Bug: 62213889
Test: SurfaceTest.TestGetLastDequeueStartTime in libgui_test
Change-Id: I1684deb09273745a3adc751554624d2257fa890e

include/gui/Surface.h

diff --git a/include/gui/Surface.h b/include/gui/Surface.h
index 8b1d106..e8dc83e 100644
--- a/include/gui/Surface.h
+++ b/include/gui/Surface.h
@@ -160,6 +160,9 @@
 
     status_t getUniqueId(uint64_t* outId) const;
 
+    // Returns the CLOCK_MONOTONIC start time of the last dequeueBuffer call
+    nsecs_t getLastDequeueStartTime() const;
+
 protected:
     virtual ~Surface();
 
@@ -421,6 +424,9 @@
     nsecs_t mLastDequeueDuration = 0;
     nsecs_t mLastQueueDuration = 0;
 
+    // Stores the time right before we call IGBP::dequeueBuffer
+    nsecs_t mLastDequeueStartTime = 0;
+
     Condition mQueueBufferCondition;
 
     uint64_t mNextFrameNumber = 1;

libs/gui/Surface.cpp

diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index 6583a62..7b2b5c3 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -501,13 +501,13 @@
 
     int buf = -1;
     sp<Fence> fence;
-    nsecs_t now = systemTime();
+    nsecs_t startTime = systemTime();
 
     FrameEventHistoryDelta frameTimestamps;
     status_t result = mGraphicBufferProducer->dequeueBuffer(&buf, &fence,
             reqWidth, reqHeight, reqFormat, reqUsage,
             enableFrameTimestamps ? &frameTimestamps : nullptr);
-    mLastDequeueDuration = systemTime() - now;
+    mLastDequeueDuration = systemTime() - startTime;
 
     if (result < 0) {
         ALOGV("dequeueBuffer: IGraphicBufferProducer::dequeueBuffer"
@@ -524,6 +524,9 @@
 
     Mutex::Autolock lock(mMutex);
 
+    // Write this while holding the mutex
+    mLastDequeueStartTime = startTime;
+
     sp<GraphicBuffer>& gbuf(mSlots[buf].buffer);
 
     // this should never happen
@@ -1699,6 +1702,11 @@
     return mGraphicBufferProducer->getUniqueId(outId);
 }
 
+nsecs_t Surface::getLastDequeueStartTime() const {
+    Mutex::Autolock lock(mMutex);
+    return mLastDequeueStartTime;
+}
+
 status_t Surface::getAndFlushRemovedBuffers(std::vector<sp<GraphicBuffer>>* out) {
     if (out == nullptr) {
         ALOGE("%s: out must not be null!", __FUNCTION__);

libs/gui/tests/Surface_test.cpp

diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index fcaa23a..81820de 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -393,6 +393,22 @@
     ASSERT_LE(removedBuffers.size(), 1u);
 }
 
+TEST_F(SurfaceTest, TestGetLastDequeueStartTime) {
+    sp<ANativeWindow> anw(mSurface);
+    ASSERT_EQ(NO_ERROR, native_window_api_connect(anw.get(), NATIVE_WINDOW_API_CPU));
+
+    ANativeWindowBuffer* buffer = nullptr;
+    int32_t fenceFd = -1;
+
+    nsecs_t before = systemTime(CLOCK_MONOTONIC);
+    anw->dequeueBuffer(anw.get(), &buffer, &fenceFd);
+    nsecs_t after = systemTime(CLOCK_MONOTONIC);
+
+    nsecs_t lastDequeueTime = mSurface->getLastDequeueStartTime();
+    ASSERT_LE(before, lastDequeueTime);
+    ASSERT_GE(after, lastDequeueTime);
+}
+
 class FakeConsumer : public BnConsumerListener {
 public:
     void onFrameAvailable(const BufferItem& /*item*/) override {}
@@ -1568,4 +1584,4 @@
     EXPECT_EQ(-1, outDisplayPresentTime);
 }
 
-}
+} // namespace android