Verification failure in SPECJVM2008.scimark.fft.small on Windows/32bit

[Volker Simonis]

Hi Tom,

I ran the benchmark all day and I couldn't reproduce the problem
neither with -XX:UseSSE=0 nor with -XX:UseSSE=1 although I havent done
that many runs with -XX:UseSSE=1 like with -XX:UseSSE=0. It seems the
problem only shows up with -XX:UseSSE=2 or higher. I'll start a run
with "-XX:UseSSE=2 -XX:+CheckJNICalls" now and post the results
tomorrow. I have also found some other options which may be worth
trying them out: -XX:+AlwaysRestoreFPU and -XX:+VerifyFPU where the
last one is only available in the debug build.

I've noticed that the tests uses a java.lang.ThreadLocal double array
to store and compute the values. May this be a problem perhaps?

Did you had a chance to reproduce the problem?

Regards,
Volker

On 10/29/08, Tom Rodriguez <Thomas.Rodriguez at sun.com> wrote:
> I haven't seen this before, though I pretty much never benchmark on windows.
>  Is the use of -XX:+CITime required? have you tried debug builds?  Does it
> reproduce with -XX:UseSSE=0?  It might be interesting to run with
> -XX:+CheckJNICalls which will verify the various fp control words have the
> right value.  I'll see if I can reproduce it here.
>
>  tom
>
>
>  On Oct 29, 2008, at 11:55 AM, Volker Simonis wrote:
>
>
> > Hi,
> >
> > we have problems with SPECJVM2008 on Windows/x86 machines with at
> > least 4 cores and at least 4 benchmark threads. The benchmark
> > reproducible fails in the result verification of the sub-benchmark
> > scimark.fft.small (however in random places).
> >
> > We could reproduce the problem with JDK 6u7 and 6u10 as well as with
> > the latest JDK 7b38 however only for the 32-bit Windows versions.
> >
> > Because the problem occurs with both, C1 and C2 and because the
> > problem isn't reproducible neither with  -Xint, nor with the 64-bit
> > Windows or the Linux JDK, we think that this may be a problem in the
> > HotSpot runtime (perhaps a timing/concurrency problem with the
> > handling of 64-bit doubles in a 32-bit JDK on multi core machines?),
> > but this is only a wild guess.
> >
> > We also observed that all the files (JDK, test classes and result
> > files) had to be on the local host in order to reproduce the problem
> > and we had the impression that the benchmark fails more quickly on
> > Intel XEON, compared to AMD Opteron (we tested on the following
> > hardware: Intel (2x XEON (with HT), 3.4GHz, 8GB, MS Win Server 2003
> > Enterprise x64, SP1) and AMD (4x Opteron 270, 2.0GHz, 9GB, MS Win
> > Server 2003 Enterprise x64, SP1)).
> >
> > Has anybody else already observed this problem? Is this perhaps an
> > issue of SPECJVM2008.scimark.fft.small?
> >
> > Any comments would be highly appreciated!
> >
> > Regards,
> > Volker
> >
> > PS: JVM2008 is available from
> http://www.spec.org/download.html
> >
> > PPS: here's the command line we used for the tests: java -server
> > -XX:+CITime -Djava.io.tmpdir=tmp -jar SPECjvm2008.jar -ikv -wt 30 -it
> > 60 -bt 4 --base scimark.fft.small scimark.fft.small scimark.fft.small
> > scimark.fft.small scimark.fft.small scimark.fft.small
> > scimark.fft.small scimark.fft.small scimark.fft.small
> > scimark.fft.small scimark.fft.small scimark.fft.small
> > scimark.fft.small scimark.fft.small scimark.fft.small
> > scimark.fft.small scimark.fft.small scimark.fft.small
> > scimark.fft.small scimark.fft.small
> >
>
>