On Wed, 19 Feb 2025 06:35:38 GMT, Thomas Stuefe <stu...@openjdk.org> wrote:
> > > Hi Thomas, this looks very useful, thanks! I will run some > > > Oracle-internal functional and performance testing and come back with the > > > results next week. > > > > > > Functional test results (Oracle internal tier1-tier5) look good. > > I measured C2 execution time before and after the changeset using DaCapo 23 > > and did not find any statistically significant difference, except for a > > 2-3% regression on the jython benchmark (using large input size). This > > small regression is IMO acceptable, particularly given that these changes > > can be seen as an investment to improve compiler resource utilization in > > the long run. > > Hi @robcasloz, interesting, I did not expect this. What did you measure? With > Compilation statistic vs without, or with old vs new, but both enabled? > (best, give me both sets of command line args) I measured and compared C2 speed in bytecodes/s as reported by `-XX:+CITime` (averaged over a number of repetitions). I wanted to test that the feature does not affect C2's execution time when not used, so I simply compared C2 compilation speed for `jdk-25+10` vs. `jdk-25+10` with this changeset applied on top (both release builds) and `-XX:+CITime -Xbatch -XX:-TieredCompilation` on both builds (the last two flags for better stability across benchmark repetitions). I could observe the regression on both linux-x64 and macosx-aarch64 platforms. Let me know if you need more details. ------------- PR Comment: https://git.openjdk.org/jdk/pull/23530#issuecomment-2668094516
