RFR(XS) 8046289: compiler/6340864/TestLongVect.java timeout with

Rickard Bäckman rickard.backman at oracle.com
Tue Jul 8 05:52:16 UTC 2014


Thank you for the review.

On 07/07, Vladimir Ivanov wrote:
> Looks good.
> 
> Best regards,
> Vladimir Ivanov
> 
> On 7/3/14 4:37 PM, Rickard Bäckman wrote:
> >Vladimir, Tobias
> >
> >I've looked into something that tries to find out when we have "good
> >enough" profiling information. Since the bug I've been working on only
> >happens with the -Xcomp flag, I've tried to special case that instead so
> >that we don't put uncommon traps when running with -Xcomp since the
> >profiling information usually is pretty bad.
> >
> >Updated webrev: http://cr.openjdk.java.net/~rbackman/8046289.3/
> >
> >Thanks
> >/R
> >
> >On 07/01, Tobias Hartmann wrote:
> >>Hi,
> >>
> >>>Some background: Tobias and me have been looking at JDK-8014830
> >>>[1] and JDK-8030976 fixed the problem. I suspect that this change
> >>>will return 8014830.
> >>
> >>I just tested the changes and the bug (JDK-8014830) appears again.
> >>The problem is that no uncommon trap is added after the first loop
> >>and therefore the second loop, especially the call to inc(), is not
> >>profiled. The compiler assumes that the call site is never executed
> >>and does not inline inc().
> >>
> >>I agree with Vladimir that we should not special case loop exits but
> >>find a solution for the case were we only have limited or no profile
> >>information.
> >>
> >>Best,
> >>Tobias
> >>
> >>>
> >>>Best regards,
> >>>Vladimir Ivanov
> >>>
> >>>[1] https://bugs.openjdk.java.net/browse/JDK-8014830
> >>>
> >>>On 6/30/14 11:26 AM, Rickard Bäckman wrote:
> >>>>Reviews please?
> >>>>
> >>>>Thanks
> >>>>/R
> >>>>
> >>>>On 06/23, Rickard Bäckman wrote:
> >>>>>Hi,
> >>>>>
> >>>>>a test started to timeout after JDK-8030976 was pushed. The
> >>>>>test was run
> >>>>>with -Xcomp flag, so the profiling data available is non-existing or
> >>>>>small. For some cases that meant that if a loop had at least 1
> >>>>>iteration
> >>>>>executed it would look like the loop would always take the backedge and
> >>>>>never end and we would generate an uncommon trap on the loop exit.
> >>>>>
> >>>>>The small change checks if the block we are considering turning into an
> >>>>>uncommon trap is a loop exit.
> >>>>>
> >>>>>Bug: https://bugs.openjdk.java.net/browse/JDK-8046289
> >>>>>Webrev: http://cr.openjdk.java.net/~rbackman/8046289/
> >>>>>
> >>>>>Thanks
> >>>>>/R
> >>>>
> >>>>
> >>
/R
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