On 01/07/2020, 18:40, "Zidenberg, Tsahi" <tsa...@amazon.com> wrote:
> Outline-atomics is a gcc compilation flag that adds runtime detection of > weather or not the cpu > supports atomic instructions. CPUs that don't support atomic instructions > will use the old > load-exclusive/store-exclusive instructions. If a different compilation flag > defined an architecture > that unconditionally supports atomic instructions (e.g. -march=armv8.2), the > outline-atomic flag > will have no effect. > > The patch was tested to improve pgbench simple-update by 10% and sysbench > write-only by 3% > on a 64-core armv8.2 machine (AWS m6g.16xlarge). Select-only and read-only > benchmarks were > not significantly affected, and neither was performance on a 16-core armv8.0 > machine that does > not support atomic instructions (AWS a1.4xlarge). > > The patch uses an existing configure.in macro to detect compiler support of > the flag. Checking for > aarch64 machine is not strictly necessary, but was added for readability. Added a commitfest entry: https://commitfest.postgresql.org/29/2637/ Thank you! Tsahi
