Odd decrease of benchmark throughput

[Dávid Karnok]

Thank you for the answer. I guess I'd need xperf for Windows but that tool
is Win 8+. I'll try my luck with JITWatch again to see the difference in C1
and C2 assemblies.

2016-09-06 16:00 GMT+02:00 Aleksey Shipilev <ashipile at redhat.com>:

> On 09/06/2016 01:05 PM, Dávid Karnok wrote:
> > # Run progress: 16,67% complete, ETA 00:01:47
> > # Fork: 1 of 1
> > # Warmup Iteration   1: 622,250 ops/s
> > # Warmup Iteration   2: 646,154 ops/s
> > # Warmup Iteration   3: 637,035 ops/s
> > # Warmup Iteration   4: 639,014 ops/s
> > # Warmup Iteration   5: 645,212 ops/s
> > Iteration   1: 648,120 ops/s
> > Iteration   2: 647,042 ops/s
> > Iteration   3: 650,176 ops/s
> > Iteration   4: 335,979 ops/s
> > Iteration   5: 195,415 ops/s
> >
> > (Running Windows 7 x64, Java 8u102, i7 4790)
> >
> > Please advise.
>
> We have seen the behavior like that before.
>
> The way to further diagnose this: prepare two runs where measurement
> phase a) has only 650 ops/s iterations; b) has only 195 ops/s iterations
> -- vary warmup/measurement durations to fit. After that, -prof perfasm
> both runs and see where the difference in profiles is. perfasm takes
> only the measurement phase in the consideration.
>
> 99% bet is on different compilation, and it is important to know what
> exactly compiled differently in 195 ops/sec iterations.
>
> Thanks,
> -Aleksey
>



-- 
Best regards,
David Karnok