commit 4013595d91898c5a18fbc480cbd4023c4307ec62
author Alex Light <allight@google.com> Fri Jul 28 08:30:35 2017 -0700
committer Alex Light <allight@google.com> Fri Jul 28 08:30:35 2017 -0700
tree e90084f96947217fb5339c9e6fabfbe1c0fbdcc3
parent 2e53f8f69f8c4175085e337445ec42aa045a2f7f

Make 1917 less flaky

We were racing the target thread slightly which meant that the output
could change as the target thread is in an unexpected position when we
dump it's stack. This makes sure we wait until the target thread
actually goes to sleep before dumping its stack.

Bug: 64134910
Test: ./test.py --host -j50
Change-Id: Ifaf9686e3fa9a1991858f9f0119e589e83169640

test/1917-get-stack-frame/expected.txt

diff --git a/test/1917-get-stack-frame/expected.txt b/test/1917-get-stack-frame/expected.txt
index 26217e6..4c9efcf 100644
--- a/test/1917-get-stack-frame/expected.txt
+++ b/test/1917-get-stack-frame/expected.txt
@@ -1,33 +1,33 @@
 Recurring 5 times
 'private static native art.StackTrace$StackFrameData[] art.StackTrace.nativeGetStackTrace(java.lang.Thread)' line: -1
 'public static art.StackTrace$StackFrameData[] art.StackTrace.GetStackTrace(java.lang.Thread)' line: 60
-'public void art.Test1917$StackTraceGenerator.run()' line: 81
-'public void art.Test1917$RecurCount.doRecur(int)' line: 103
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.run()' line: 96
-'public static void art.Test1917.run() throws java.lang.Exception' line: 132
+'public void art.Test1917$StackTraceGenerator.run()' line: 82
+'public void art.Test1917$RecurCount.doRecur(int)' line: 104
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.run()' line: 97
+'public static void art.Test1917.run() throws java.lang.Exception' line: 133
 Recurring 5 times on another thread
 'private static native art.StackTrace$StackFrameData[] art.StackTrace.nativeGetStackTrace(java.lang.Thread)' line: -1
 'public static art.StackTrace$StackFrameData[] art.StackTrace.GetStackTrace(java.lang.Thread)' line: 60
-'public void art.Test1917$StackTraceGenerator.run()' line: 81
-'public void art.Test1917$RecurCount.doRecur(int)' line: 103
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.run()' line: 96
+'public void art.Test1917$StackTraceGenerator.run()' line: 82
+'public void art.Test1917$RecurCount.doRecur(int)' line: 104
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.run()' line: 97
 Recurring 5 times on another thread. Stack trace from main thread!
 'public void java.util.concurrent.Semaphore.acquire() throws java.lang.InterruptedException' line: <NOT-DETERMINISTIC>
 'public void art.Test1917$ThreadPauser.run()' line: 46
-'public void art.Test1917$RecurCount.doRecur(int)' line: 103
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.doRecur(int)' line: 101
-'public void art.Test1917$RecurCount.run()' line: 96
+'public void art.Test1917$RecurCount.doRecur(int)' line: 104
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.doRecur(int)' line: 102
+'public void art.Test1917$RecurCount.run()' line: 97

test/1917-get-stack-frame/src/art/Test1917.java

diff --git a/test/1917-get-stack-frame/src/art/Test1917.java b/test/1917-get-stack-frame/src/art/Test1917.java
index 1057235..def7530 100644
--- a/test/1917-get-stack-frame/src/art/Test1917.java
+++ b/test/1917-get-stack-frame/src/art/Test1917.java
@@ -51,6 +51,7 @@
 
     public void waitForOtherThreadToPause() throws Exception {
       sem_wakeup_main.acquire();
+      while (!sem_wait.hasQueuedThreads()) {}
     }
 
     public void wakeupOtherThread() throws Exception {