Hi Daniil,
Just my two cents about this :)
I was looking at this and wondered if it made sense to fix
the test this way (I always worry about simplifying a test and
losing coverage). I understand the bug is that it is possible
that between both calls, Graal could add some frames and
therefore might trip this test:
- if (frameStackSize < frameCount) {
However, by removing the test altogether and only relying
on the suspended frames, are we not reducing our coverage of
the test (basically never really testing the running threads
anymore, only the suspended ones?).
Alternatively, when we look at this code and the hypothesis
of Graal stacks "slipping in between calls", two cases could
occur:
A) The Graal frames are present in the first call but not
the second
B) The Graal frames are present in the second call but
not the first
In the (B) case, the test would not trip, as frameStackSize
would be >= frameCount so that is not an issue.
In the (A) case, we could simply recall the frameCount and
assure ourselves the frames have disappeared, no?
Something like:
if (frameStackSize < frameCount) {
// This can occur for Graal if graal frames
crept in. Call getFrameCount again and see if they have
disappeared since
// frameStackSize seems to say so.
... insert call here and a new check...
NSK_COMPLAIN5("Too small stack of %s thread
#%d (%s):\n"
"# getStackTrace(): %d\n"
"# getFrameCount(): %d\n",
kind, i,
threadsDesc[i].threadName,
(int)frameStackSize,
(int)frameCount);
nsk_jvmti_setFailStatus();
}
Just my 2 cents because I worry about simplifying a test
for Graal but losing coverage in the general case,
Jc
Please review the change that
fixes 4 JVMTI tests when running with Graal.
One of the checks these tests perform compares the number of
frames in the thread's stack returned by JVMTI
GetFrameCount() with the number of frames entries returned
by JVMTI GetStackTrace(). The thread to be tested executes
arithmetic operations in the loop so the consequent calls of
GetFrameCount() or/and GetStackTrace() should return the
stack trace of the same depth.
However, with Graal on, additional "adjustCompilationLevel"
frames could appear on the stack trace, e.g.:
adjustCompilationLevel:166, HotSpotGraalCompilerFactory
(org.graalvm.compiler.hotspot)
adjustCompilationLevel:504, HotSpotJVMCIRuntime
(jdk.vm.ci.hotspot)
testedMethod:56, Test$Runner
run:67, Test$Runner
that results in the stack depth reported by the first
invocation of GetFrameCount() or GetStackTrace() might
differ from the stack depth reported by the consequent calls
of the same methods.
The fix modifies the tests to ensure the check that
GetFrameCount () and GetStackTrace() report the same stack
depth is performed only if the thread is suspended. For two
tests
(vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/TestDescription.java
and
vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t001/TestDescription.java)
such check for suspended threads already exists so in these
tests the problematic check was not modified by just
removed.
Issue: https://bugs.openjdk.java.net/browse/JDK-8209585
Webrev: http://cr.openjdk.java.net/~dtitov/8209585/webrev.01
Thanks,
Daniil
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