https://bugs.kde.org/show_bug.cgi?id=523843
--- Comment #7 from Martin Cermak <[email protected]> --- I've been measuring `perf stat -r 20 memcheck/memcheck-x86-linux none/tests/x86/sse4-x86` and comparing this with and without -mstack-alignment=16 -mstackrealign. Although the cpu_core/instructions is clearly slightly higher with realign in place (roughly + 5%), the IPC (instructions per cycle count) is higher with alignment (roughly +7%) which means less cycles overall with realignment in place. Total elapsed time dropped from 1.990835071 to 1.970732172, which actually means that with the realignment in place, none/tests/x86/sse4-x86 is slightly (1%) faster. For a non-sse testcase, I've picked none/tests/x86/lzcnt32. cpu_core/instructions raise +2.7%, IPC: no change, total elapsed time raised from 0.489375488 sec to 0.496833509, which seems like a minor (1.5%) regression. Of course, we have more non-sse tests than sse tests . But the impact of the stack realignment per patch from comment #4 seems negligible to me. -- You are receiving this mail because: You are watching all bug changes.
