diff options
| author | Andy Lutomirski <[email protected]> | 2011-05-23 09:31:26 -0400 |
|---|---|---|
| committer | Thomas Gleixner <[email protected]> | 2011-05-24 14:51:28 +0200 |
| commit | 3729db5ca2b2000c660e5a5d0eb68b1053212cab (patch) | |
| tree | a8b038145eadd067f92798adb4292532eccedfba /tools/perf/util/scripting-engines/trace-event-perl.c | |
| parent | 057e6a8c660e95c3f4e7162e00e2fee1fc90c50d (diff) | |
x86-64: Don't generate cmov in vread_tsc
vread_tsc checks whether rdtsc returns something less than
cycle_last, which is an extremely predictable branch. GCC likes
to generate a cmov anyway, which is several cycles slower than
a predicted branch. This saves a couple of nanoseconds.
Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Borislav Petkov <[email protected]>
Link: http://lkml.kernel.org/r/%3C561280649519de41352fcb620684dfb22bad6bac.1306156808.git.luto%40mit.edu%3E
Signed-off-by: Thomas Gleixner <[email protected]>
Diffstat (limited to 'tools/perf/util/scripting-engines/trace-event-perl.c')
0 files changed, 0 insertions, 0 deletions