Messages in this thread | | | Date | Mon, 27 Apr 2015 11:14:15 -0700 | Subject | Re: [PATCH] x86_64, asm: Work around AMD SYSRET SS descriptor attribute issue | From | Linus Torvalds <> |
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On Mon, Apr 27, 2015 at 9:40 AM, Borislav Petkov <bp@alien8.de> wrote: > > Either way, the NOPs-version is faster and I'm running the test with the > F16h-specific NOPs to see how they perform.
Btw, please don't use the "more than three 66h overrides" version. Sure, that's what the optimization manual suggests if you want single-instruction decode for all sizes up to 15 bytes, but I think we're better off with the two-nop case for sizes 12-15) (4-byte nop followed by 8-11 byte nop).
Because the "more than three 66b prefixes" really performs abysmally on some cores, iirc.
Linus
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