On Thu, 7 Aug 2025 16:47:04 GMT, Francesco Andreuzzi <d...@openjdk.org> wrote:
> In this PR I propose to refresh the included headers in hotspot > `precompiled.hpp`. The current set of precompiled headers was refreshed in > 2018, 7 years ago. I repeated the same operations and measurements after > refreshing the set of precompiled headers according to the current usage > frequency. > > These are the results I observed. Depending on the platform, the improvement > is between 10 and 20% in terms of total work (user+sys). The results are in > seconds. > > > linux-x64 GCC > master real 81.39 user 3352.15 sys 287.49 > JDK-8365053 real 81.94 user 3030.24 sys 295.82 > > linux-x64 Clang > master real 43.44 user 2082.93 sys 130.70 > JDK-8365053 real 38.44 user 1723.80 sys 117.68 > > linux-aarch64 GCC > master real 1188.08 user 2015.22 sys 175.53 > JDK-8365053 real 1019.85 user 1667.45 sys 171.86 Also, maybe check in the generation script as well? I think a subfolder here would be fine: https://github.com/openjdk/jdk/tree/master/src/utils. It would be nice if the output of that script could be simply piped into `precompiled.hpp`, so we can use it later without extra work. We can, technically, hook it up a similar way SortIncludes.java is currently done, but I think it is unnecessary at this point. In a perfect world we would not be needing precompiled headers. In less ideal world, having a jtreg test that warns us that a new popular header appeared, or that older header is not as popular anymore, would be handy. Again, this is something out of scope for this PR. ------------- PR Comment: https://git.openjdk.org/jdk/pull/26681#issuecomment-3165135998
