Odd decrease of benchmark throughput
akarnokd at gmail.com
Tue Sep 6 14:18:12 UTC 2016
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.
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