diff options
author | Borislav Petkov <[email protected]> | 2016-01-26 22:12:05 +0100 |
---|---|---|
committer | Ingo Molnar <[email protected]> | 2016-01-30 11:22:18 +0100 |
commit | bc696ca05f5a8927329ec276a892341e006b00ba (patch) | |
tree | a8200bfe9677aa30a11b53e8fd6215aaeb3a4a96 /tools/perf/scripts/python | |
parent | cd4d09ec6f6c12a2cc3db5b7d8876a325a53545b (diff) |
x86/cpufeature: Replace the old static_cpu_has() with safe variant
So the old one didn't work properly before alternatives had run.
And it was supposed to provide an optimized JMP because the
assumption was that the offset it is jumping to is within a
signed byte and thus a two-byte JMP.
So I did an x86_64 allyesconfig build and dumped all possible
sites where static_cpu_has() was used. The optimization amounted
to all in all 12(!) places where static_cpu_has() had generated
a 2-byte JMP. Which has saved us a whopping 36 bytes!
This clearly is not worth the trouble so we can remove it. The
only place where the optimization might count - in __switch_to()
- we will handle differently. But that's not subject of this
patch.
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'tools/perf/scripts/python')
0 files changed, 0 insertions, 0 deletions