RFR: 8373026: C2 SuperWord and Vector API: vector algorithms test and benchmark [v4]

[Emanuel Peter]

On Mon, 19 Jan 2026 08:23:50 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> My personal preference is `Level.Trial`. When I work with a microbenchmark, the fewer "moving parts" it has the better. It's easy to spot fork-to-fork variance. Not so much with iteration variance where a single outlier can be caused by many factors.
>
> @iwanowww Why is fork variance easier to spot than iteration variance?
> 
> I suppose I can try doing the setup per fork. But that does drive up the runtime of the benchmark, because you need to do warmup for each fork. But I suppose you think that is worth it?

I now am using Forks. But it does indeed drive up the runtime. I need about a 5-sec warmup for some benchmarks until they really reach peak performance. Multiply that with multiple forks, and it gets slow.

Not great, but I can live with that.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28639#discussion_r2705224082