WL#10343: Switch GCC optimization from -O3 to -O2
Affects: Server-8.0 — Status: Complete
We use the GCC that is included in each Linux distro. The exception is RHEL/OEL, where the GCC is so old that we use Red Hat's “Developer Toolsets”, which contain newer versions. We have now upgraded from Developer Toolset 3 (GCC 4.9) to 6 (GCC 6.2), and all new builds (including our official binaries) on these platforms are done using Toolset 6. To our knowledge, all Linux distros use optimization switch -O2, and we will use the same optimization level. SysQA performance testing has shown 0-6% performance improvement in Sysbench by switching from -O3 to -O2, likely due to the reduction in binary size with -O2. With the new Toolset 6, several DBT3 queries show a very significant performance improavement of up to 50%.
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