Improving jank tests diagnostics

When there were 0 total frames, ProfileData generates something like:
Janky frames: 0 (nan%)

Then the test fails to parse it, and ends up with a mysterious
"Failed to parse NUM_JANKY" diag (see the bug).

Making the case 0/0 a 0%.

Bug: 77528721
Test: atest google/perf/jank/SystemUI/UbSystemUIJankTests:android.platform.systemui.tests.jank.LauncherJankTests#testOpenAllAppsContainer
Change-Id: Ib65b80dc689f7b6ee06b108114ffd7de9d739721

1 files changed, 2 insertions, 1 deletions

diff --git a/libs/hwui/ProfileData.cpp b/libs/hwui/ProfileData.cpp
index f9cf54998032..16966619aace 100644
--- a/libs/hwui/ProfileData.cpp
+++ b/libs/hwui/ProfileData.cpp
@@ -104,7 +104,8 @@ void ProfileData::dump(int fd) const {
     dprintf(fd, "\nStats since: %" PRIu64 "ns", mStatStartTime);
     dprintf(fd, "\nTotal frames rendered: %u", mTotalFrameCount);
     dprintf(fd, "\nJanky frames: %u (%.2f%%)", mJankFrameCount,
-            (float)mJankFrameCount / (float)mTotalFrameCount * 100.0f);
+            mTotalFrameCount == 0 ? 0.0f :
+                (float)mJankFrameCount / (float)mTotalFrameCount * 100.0f);
     dprintf(fd, "\n50th percentile: %ums", findPercentile(50));
     dprintf(fd, "\n90th percentile: %ums", findPercentile(90));
     dprintf(fd, "\n95th percentile: %ums", findPercentile(95));