On Wed, 30 Oct 2024 02:09:46 GMT, Liang Mao <l...@openjdk.org> wrote:
>> We disabled tiered compilation to force everything to compile through C2 to >> get more consistent results. > > @earthling-amzn ，thanks for providing your options. Looks like disabling > pacing would help the score. > > -XX:+UseShenandoahGC -XX:+UnlockExperimentalVMOptions > -XX:+UnlockDiagnosticVMOptions -XX:-TieredCompilation -XX:-ShenandoahPacing > -XX:+AlwaysPreTouch -XX:+DisableExplicitGC > > I guess 4 cores may not be a target configuration for pauseless GC since > generational pauseless GC requires at least 2 concurrent GC threads that > already occupy half of CPU resource. I did a rough test on 8 cores and 16 > cores according to your options. GenShen doesn't have obvious advantages with > 8 cores and Shenandoah seems to outperform genshen significantly with 16 > cores. Would you please help verify the result in your environment? > > 8 cores -Xmx8g -Xms8g: > > GenShen: > RUN RESULT: hbIR (max attempted) = 9640, hbIR (settled) = 8050, max-jOPS = > 8098, critical-jOPS = 6132 > RUN RESULT: hbIR (max attempted) = 8944, hbIR (settled) = 8574, max-jOPS = > 7781, critical-jOPS = 6130 > > Shenandoah: > RUN RESULT: hbIR (max attempted) = 9640, hbIR (settled) = 8050, max-jOPS = > 7616, critical-jOPS = 6194 > RUN RESULT: hbIR (max attempted) = 9640, hbIR (settled) = 8050, max-jOPS = > 7712, critical-jOPS = 6262 > > 16 cores -Xmx20g -Xms20g: > > GenShen: > RUN RESULT: hbIR (max attempted) = 19881, hbIR (settled) = 16584, max-jOPS = > 17694, critical-jOPS = 13274 > RUN RESULT: hbIR (max attempted) = 19881, hbIR (settled) = 18724, max-jOPS = > 17694, critical-jOPS = 13445 > Shenandoah: > RUN RESULT: hbIR (max attempted) = 23838, hbIR (settled) = 20446, max-jOPS = > 18594, critical-jOPS = 15441 > RUN RESULT: hbIR (max attempted) = 20138, hbIR (settled) = 19989, max-jOPS = > 18728, critical-jOPS = 14967 @mmyxym - I disabled Shenandoah's pacer, and find that the generational mode out performs the non-generational mode: Shen: RUN RESULT: hbIR (max attempted) = 16584, hbIR (settled) = 13837, max-jOPS = 11609, critical-jOPS = 11062 Shen: RUN RESULT: hbIR (max attempted) = 16584, hbIR (settled) = 13837, max-jOPS = 11609, critical-jOPS = 10425 Gen: RUN RESULT: hbIR (max attempted) = 16584, hbIR (settled) = 14144, max-jOPS = 13267, critical-jOPS = 12087 Gen: RUN RESULT: hbIR (max attempted) = 16584, hbIR (settled) = 13837, max-jOPS = 13267, critical-jOPS = 12151 The shared options for these runs were: "-Xmx8g -Xms8g -XX:ActiveProcessorCount=8 -XX:+UseShenandoahGC -XX:+UnlockExperimentalVMOptions -XX:MetaspaceSize=1g -XX:-ShenandoahPacing This is an aarch64 host with 16 cores and 64G of memory. ------------- PR Comment: https://git.openjdk.org/jdk/pull/21273#issuecomment-2448245419
