On Wed, 23 Mar 2022 23:17:38 GMT, Magnus Ihse Bursie <i...@openjdk.org> wrote:
>> [JDK-8247872](https://bugs.openjdk.java.net/browse/JDK-8247872) (upgrade >> HarfBuzz to 2.7.2) caused build time to go up with 24 seconds on my >> reference linux machine. This was one of the four culprits that caused a >> 25-30% build time regression over the last two years. >> >> The problem here was that the new HarfBuzz code caught really bad behaviour >> from gcc when compiling with optimizations. The official HarfBuzz build does >> not use any -O flags at all for gcc, so presumably the HarfBuzz team is: >> >> a) not thinking compiler optimization is important for the performance of >> this library, and >> b) unaware that their code causes such a headache for gcc. >> >> (Other compilers fare much better: visual studio makes no difference at all, >> and for clang just a small regression was observed.) >> >> The current optimization level was introduced by >> [JDK-8255790](https://bugs.openjdk.java.net/browse/JDK-8255790), which were >> really about moving libharfbuzz compilation back into libfontmanager. I >> could find no comments/discussion relating to the change of optimization >> level, so I assume it was incidental, and just seemed good at the time. >> >> This patch changes the optimization level to `SIZE` (which is the closest >> thing we have to no optimization level) on gcc. > > Magnus Ihse Bursie has updated the pull request incrementally with one > additional commit since the last revision: > > Update comment to show we don't care about these files. Marked as reviewed by prr (Reviewer). ------------- PR: https://git.openjdk.java.net/jdk/pull/7919
