commit 1c7938ecd30c0938f63fb84fe279892ff6a20e47
author Alec Mouri <alecmouri@google.com> Fri Sep 22 04:17:23 2023 +0000
committer Alec Mouri <alecmouri@google.com> Thu Sep 28 23:07:17 2023 +0000
tree bf508cc508b6b11fa3dfed8bc56abf1a20d072b3
parent c6e0391600bcd0d33c1478575bd2f18bccaf005f

Support injecting jank into Scheduler for testing purposes

Injects a fraction of a frame's expected present time as a jank. This is
mainly to avoid thinking about hard-coding milliseconds.

Also supports delaying this jank injection, since the Perfetto UI
currently steals any ADB session

Bug: 296636083
Test: TouchLatency + perfetto
Change-Id: If08616e68c3e7b3d6eaed6f6ff5cbc6ad444481e

services/surfaceflinger/Scheduler/Scheduler.cpp

diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index d72ae1f..68e2ce9 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -211,6 +211,17 @@
         targeters.try_emplace(id, &targeter);
     }
 
+    if (flagutils::vrrConfigEnabled() &&
+        CC_UNLIKELY(mPacesetterFrameDurationFractionToSkip > 0.f)) {
+        const auto period = pacesetterTargeter.target().expectedFrameDuration();
+        const auto skipDuration = Duration::fromNs(
+                static_cast<nsecs_t>(period.ns() * mPacesetterFrameDurationFractionToSkip));
+        ATRACE_FORMAT("Injecting jank for %f%% of the frame (%" PRId64 " ns)",
+                      mPacesetterFrameDurationFractionToSkip * 100, skipDuration.ns());
+        std::this_thread::sleep_for(skipDuration);
+        mPacesetterFrameDurationFractionToSkip = 0.f;
+    }
+
     const auto resultsPerDisplay = compositor.composite(pacesetterId, targeters);
     compositor.sample();
 

services/surfaceflinger/Scheduler/Scheduler.h

diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 5796d59..f652bb2 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -323,6 +323,11 @@
         return mFeatures.test(Feature::kSmallDirtyContentDetection);
     }
 
+    // Injects a delay that is a fraction of the predicted frame duration for the next frame.
+    void injectPacesetterDelay(float frameDurationFraction) REQUIRES(kMainThreadContext) {
+        mPacesetterFrameDurationFractionToSkip = frameDurationFraction;
+    }
+
 private:
     friend class TestableScheduler;
 
@@ -452,6 +457,9 @@
     // Timer used to monitor display power mode.
     ftl::Optional<OneShotTimer> mDisplayPowerTimer;
 
+    // Injected delay prior to compositing, for simulating jank.
+    float mPacesetterFrameDurationFractionToSkip GUARDED_BY(kMainThreadContext) = 0.f;
+
     ISchedulerCallback& mSchedulerCallback;
 
     // mDisplayLock may be locked while under mPolicyLock.