On Thu, 24 Oct 2024 13:52:57 GMT, Claes Redestad <redes...@openjdk.org> wrote:
> Many OpenJDK micros use `@Fork(jvmArgs/-Append/-Prepend)` to add JVM > reasonable or necessary flags, but when deploying and running micros we often > want to add or replace flags to tune to the machine, test different GCs, etc. > The inconsistent use of the different `jvmArgs` options make it error prone, > and we've had a few recent cases where we've not been testing with the > expected set of flags. > > This PR suggests using `jvmArgs` consistently. I think this aligns with the > intuition that when you use `jvmArgsAppend/-Prepend` intent is to add to a > set of existing flags, while if you supply `jvmArgs` intent is "run with > these and nothing else". Perhaps there are other opinions/preferences, and I > don't feel strongly about which to consolidate to as long as we do so > consistently. One argument could be made to consolidate on `jvmArgsAppend` > since that one is (likely accidentally) the current most popular (143 > compared to 59 `jvmArgsPrepend` and 18 `jvmArgs`). Hi Claes, I'm having some strange results with your JMH PR: https://github.com/openjdk/jdk/pull/21683 And my benchmark: https://github.com/openjdk/jdk/blame/master/test/micro/org/openjdk/bench/vm/compiler/VectorLoadToStoreForwarding.java Running it like this: `make test TEST="micro:vm.compiler.VectorLoadToStoreForwarding.*benchmark_03" CONF=linux-x64` And I'm getting this result: Benchmark (SIZE) (seed) Mode Cnt Score Error Units VectorLoadToStoreForwarding.VectorLoadToStoreForwardingNoSuperWord.benchmark_03 2048 0 avgt 10 4563.110 ± 64.988 ns/op VectorLoadToStoreForwarding.VectorLoadToStoreForwardingSuperWord.benchmark_03 2048 0 avgt 10 4549.337 ± 32.239 ns/op But when I revert your change, back to `jvmArgsPrepend` : Benchmark (SIZE) (seed) Mode Cnt Score Error Units VectorLoadToStoreForwarding.VectorLoadToStoreForwardingNoSuperWord.benchmark_03 2048 0 avgt 10 1040.538 ± 14.660 ns/op VectorLoadToStoreForwarding.VectorLoadToStoreForwardingSuperWord.benchmark_03 2048 0 avgt 10 4533.227 ± 5.161 ns/op It seems that with your PR, the flags don't have the intended effect any more! With your change, I see this: `# VM options: -Djava.library.path=/oracle-work/jdk-fork6/build/linux-x64/images/test/micro/native` And reverting back, I see this: `# VM options: -XX:-UseSuperWord -Djava.library.path=/oracle-work/jdk-fork6/build/linux-x64/images/test/micro/native` ------------- PR Comment: https://git.openjdk.org/jdk/pull/21683#issuecomment-2449207896
