8209585: [Graal] vmTestbase/nsk/jvmti/scenarios/sampling tests fail with "Too small stack of resumed thread"
Chris Plummer
chris.plummer at oracle.com
Fri Aug 31 16:24:51 UTC 2018
+2
Chris
On 8/30/18 4:52 PM, Alex Menkov wrote:
> +1
>
> --alex
>
> On 08/30/2018 15:43, serguei.spitsyn at oracle.com wrote:
>> Hi Daniil,
>>
>> Thank you a lot for this extra update and cleanup!
>> I feels that it has a real value in improving the tests reliability.
>>
>> Some minor comments:
>>
>> http://cr.openjdk.java.net/~dtitov/8209585/webrev.03/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/TestDescription.java.udiff.html
>>
>>
>> I'd suggest to update the fragment:
>> * Checked statements:
>> to:
>> * Checked statements for suspended threads:
>>
>> A suggestion to remove the dot in the original comment:
>>
>> * are not less than expected minimal stack depth.
>>
>>
>> http://cr.openjdk.java.net/~dtitov/8209585/webrev.03/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t002/sp02t002.c.udiff.html
>>
>>
>> Two typos are inherited taken from the original comment (numbers
>> => number, frame => frames):
>>
>> - * - compare numbers of stack frame returned
>> - * - find stck frane with expected methodID
>> + * - for suspended thread compare numbers of stack frame returned
>> + * - find stack frame with expected methodID
>>
>>
>> http://cr.openjdk.java.net/~dtitov/8209585/webrev.03/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t001/TestDescription.java.udiff.html
>>
>>
>> It is nice you fixed several pre-existed typos in the comment.
>>
>> I'd suggest to update the fragment:
>> * Checked statements:
>> to:
>> * Checked statements for suspended threads:
>>
>> The dot at the end is not needed:
>>
>> + * are not less than expected minimal stack depth.
>>
>>
>> http://cr.openjdk.java.net/~dtitov/8209585/webrev.03/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t002/TestDescription.java.udiff.html
>>
>>
>> Looks good.
>>
>>
>> http://cr.openjdk.java.net/~dtitov/8209585/webrev.03/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t002/sp06t002.c.udiff.html
>>
>>
>> Two typos are inherited taken from the original comment (numbers
>> => number, frame => frames):
>>
>> - * - compare numbers of stack frame returned
>> - * - find stck frane with expected methodID
>> + * - for suspended thread compare numbers of stack frame returned
>> + * - find stack frame with expected methodID
>>
>>
>> No updated webrev is needed if you fix the above.
>>
>> Thanks,
>> Serguei
>>
>>
>> On 8/30/18 14:28, Daniil Titov wrote:
>>> Hi Serguei,
>>>
>>> Please review a new version of the webrev that has the suggested
>>> changes applied for two tests:
>>> test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/TestDescription.java
>>> and
>>> test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t001/TestDescription.java.
>>>
>>> The other two tests
>>> test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t002/TestDescription.java
>>> test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP06/sp06t002/TestDescription.java
>>> use stack trace to check that the list of stack frames includes the
>>> frame for the tested method so I left them unchanged ( they still do
>>> test both running and suspended threads).
>>>
>>> I also fixed the comments to make them relevant to what the tests
>>> actually do.
>>>
>>> Webrev:http://cr.openjdk.java.net/~dtitov/8209585/webrev.03/
>>> Issue:https://bugs.openjdk.java.net/browse/JDK-8209585
>>>
>>> Thanks!
>>> Daniil
>>>
>>>
>>> On 8/27/18, 8:29 PM,"serguei.spitsyn at oracle.com"
>>> <serguei.spitsyn at oracle.com> wrote:
>>>
>>> Hi Daniil and Jc,
>>> I'm thinking if it make sense to call checkThreads()
>>> when the threads
>>> are not suspended.
>>> In fact, it does not check much for non-suspended threads now.
>>> As an example, consider the test:
>>> http://cr.openjdk.java.net/~dtitov/8209585/webrev.02/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP02/sp02t001/sp02t001.c.frames.html
>>> The call to JVMTI GetStackTrace() for non-suspended case
>>> is not really
>>> needed.
>>> It is only to print the frameStackSize value:
>>> 275 NSK_DISPLAY1(" stack depth: %d\n",
>>> (int)frameStackSize);
>>> The only real check left is:
>>> 277 /* check frame count */
>>> 278 if (frameCount < threadsDesc[i].minDepth) {
>>> 279 NSK_COMPLAIN5("Too few frameCount of %s
>>> thread #%d (%s):\n"
>>> 280 "# got frameCount: %d\n"
>>> 281 "# expected minimum: %d\n",
>>> 282 kind, i,
>>> threadsDesc[i].threadName,
>>> 283 (int)frameCount,
>>> threadsDesc[i].minDepth);
>>> 284 nsk_jvmti_setFailStatus();
>>> 285 }
>>> I don't think this check has a real value for
>>> non-suspended case.
>>> A real value for us is simplicity and reliability.
>>> My suggestion is to get rid of "suspended" parameter and
>>> all non-suspended call of the checkThreads.
>>> But, please, note, the comments will need another update. :)
>>> Jc, nice catch about the comments!
>>> Thanks,
>>> Serguei
>>> On 8/27/18 17:57, Daniil Titov wrote:
>>> > Hi JC, Serguei, and Alex,
>>> >
>>> > Please review an updated version of the webrev that has these
>>> comments fixed.
>>> >
>>> > Webrev:http://cr.openjdk.java.net/~dtitov/8209585/webrev.02/
>>> > Issue:https://bugs.openjdk.java.net/browse/JDK-8209585
>>> >
>>> > Thanks!
>>> > Daniil
>>> >
>>> >
>>> >
>>> > From:
>>> serviceability-dev<serviceability-dev-bounces at openjdk.java.net> on
>>> behalf of Daniil Titov<daniil.x.titov at oracle.com>
>>> > Date: Monday, August 27, 2018 at 11:05 AM
>>> > To: JC Beyler<jcbeyler at google.com>,<serguei.spitsyn at oracle.com>
>>> > Cc:<serviceability-dev at openjdk.java.net>
>>> > Subject: Re: 8209585: [Graal]
>>> vmTestbase/nsk/jvmti/scenarios/sampling tests fail with "Too small
>>> stack of resumed thread"
>>> >
>>> > Hi Jc,
>>> >
>>> > Thank you for spotting this! I will send on review an
>>> updated webrev with these comments fixed.
>>> >
>>> > Best regards,
>>> > Daniil
>>> >
>>> > From: JC Beyler<jcbeyler at google.com>
>>> > Date: Monday, August 27, 2018 at 10:41 AM
>>> > To:<serguei.spitsyn at oracle.com>
>>> >
>>> Cc:<daniil.x.titov at oracle.com>,<serviceability-dev at openjdk.java.net>
>>> > Subject: Re: RFR: 8209585: [Graal]
>>> vmTestbase/nsk/jvmti/scenarios/sampling tests fail with "Too small
>>> stack of resumed thread"
>>> >
>>> > Hi Serguei,
>>> >
>>> > Fair enough, at least this removes a bit of the chance of
>>> flakiness :-)
>>> >
>>> > Should we at least clean up the comment for methods that are
>>> changed?
>>> >
>>> > /**
>>> > * Testcase: check tested threads
>>> > * - invoke getFrameCount() for each thread
>>> > * - check if frameCount is not less than minimal stack
>>> depth
>>> > * - invoke getStackTrace() for each thread
>>> > * - check if stack depth is not less than frameCount
>>> > * - for suspended thread check if stack depth is equal
>>> to frameCount
>>> > *
>>> > * Returns NSK_TRUE if test may continue; or NSK_FALSE for
>>> test break.
>>> > */
>>> > static int checkThreads(int suspended, const char* kind) {
>>> >
>>> > The " * - check if stack depth is not less than
>>> frameCount" is no longer done with this webrev.
>>> >
>>> > Thanks,
>>> > Jc
>>> >
>>> >
>>> > On Sun, Aug 26, 2018 at 9:52
>>> PMmailto:serguei.spitsyn at oracle.com
>>> <mailto:serguei.spitsyn at oracle.com> wrote:
>>> > Hi Jc,
>>> >
>>> > Initially, I has the same concern.
>>> > But now I think there is no point to take these values on
>>> non-suspended threads.
>>> > It has to be good enough to compare the values taken on
>>> suspended threads only.
>>> >
>>> > Thanks,
>>> > Serguei
>>> >
>>> >
>>> > On 8/24/18 16:49, JC Beyler wrote:
>>> > 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
>>> >
>>> >
>>> >
>>> > On Thu, Aug 23, 2018 at 8:29 PM Daniil
>>> Titov<mailto:daniil.x.titov at oracle.com> wrote:
>>> > 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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