RFR: 8339983: [s390x] secondary_super_cache does not scale well: C1 and interpreter [v4]

[Andrew Haley]

On 11/27/24 15:58, Amit Kumar wrote:
> On Wed, 27 Nov 2024 15:48:29 GMT, Lutz Schmidt <lucy at openjdk.org> wrote:
> 
>> Are there any performance figures? Does the change help, or at least do no harm, on s390?
> 
> I do but they don't look interesting.

With the patch you should see this:

-XX:TieredStopAtLevel=1 -XX:+UnlockDiagnosticVMOptions -XX:+UseSecondarySupersCache -XX:-UseSecondarySupersTable

Benchmark                                   Mode  Cnt    Score     Error  Units
SecondarySuperCacheInterContention.test     avgt    5  176.328 ±  69.341  ns/op
SecondarySuperCacheInterContention.test:t1  avgt    5  173.024 ±  29.227  ns/op
SecondarySuperCacheInterContention.test:t2  avgt    5  179.633 ± 110.211  ns/op

-XX:TieredStopAtLevel=1

Benchmark                                   Mode  Cnt  Score   Error  Units
SecondarySuperCacheInterContention.test     avgt    5  5.156 ± 0.855  ns/op
SecondarySuperCacheInterContention.test:t1  avgt    5  5.225 ± 1.604  ns/op
SecondarySuperCacheInterContention.test:t2  avgt    5  5.087 ± 0.740  ns/op

assuming you have >1 core. Try also SecondarySuperCacheIntraContention.test

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671