On Thu, 3 Feb 2022 07:20:28 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
> I was looking for easy things to do to improve `java.lang.invoke` cold
> performance. One of the things is inlining `VarForm.getMemberName` a bit, so
> that interpreter does not have to call through `getMemberNameOrNull`.
>
> There is direct VarHandle benchmark in our corpus:
>
>
> $ CONF=linux-x86_64-server-release make run-test
> TEST=micro:java.lang.invoke.VarHandleExact
> MICRO="TIME=200ms;WARMUP_TIME=200ms;VM_OPTIONS=-Xint"
>
> Benchmark Mode Cnt Score Error Units
>
> # -Xint
> # Baseline
> VarHandleExact.exact_exactInvocation avgt 30 714.041 ± 5.882 ns/op
> VarHandleExact.generic_exactInvocation avgt 30 641.570 ± 11.681 ns/op
> VarHandleExact.generic_genericInvocation avgt 30 1336.571 ± 11.873 ns/op
>
> # -Xint
> # Patched
> VarHandleExact.exact_exactInvocation avgt 30 678.495 ± 10.752 ns/op
> ; +5%
> VarHandleExact.generic_exactInvocation avgt 30 573.320 ± 5.100 ns/op
> ; +11%
> VarHandleExact.generic_genericInvocation avgt 30 1338.593 ± 14.275 ns/op
>
> # (server, default)
> # Baseline
> VarHandleExact.exact_exactInvocation avgt 30 0.620 ± 0.079 ns/op
> VarHandleExact.generic_exactInvocation avgt 30 0.602 ± 0.063 ns/op
> VarHandleExact.generic_genericInvocation avgt 30 10.521 ± 0.065 ns/op
>
> # (server, default)
> # Patched
> VarHandleExact.exact_exactInvocation avgt 30 0.621 ± 0.070 ns/op
> VarHandleExact.generic_exactInvocation avgt 30 0.601 ± 0.061 ns/op
> VarHandleExact.generic_genericInvocation avgt 30 10.499 ± 0.070 ns/op
>
>
> Additional testing:
> - [x] Linux x86_64 fastdebug `tier1`
> - [x] Linux x86_64 fastdebug `tier2`
> - [x] Linux x86_64 fastdebug `tier3`
Marked as reviewed by vlivanov (Reviewer).
src/java.base/share/classes/java/lang/invoke/VarForm.java line 112:
> 110: @ForceInline
> 111: final MemberName getMemberName(int mode) {
> 112: MemberName mn = memberName_table[mode];
It makes sense to leave a comment here why inlining `getMemberNameOrNull()`
makes sense. Otherwise, looks good.
-------------
PR: https://git.openjdk.java.net/jdk/pull/7333
