Messages in this thread | | | Date | Wed, 30 Jun 2010 10:13:12 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 3/4, v2] x86: enlightenment for ticket spin locks - eliminate NOPs introduced by first patch |
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On 06/30/2010 12:07 AM, Jan Beulich wrote: >> >> If you're stretching (bloating) them anyway, perhaps we should be using >> "add" instructions instead, with their better EFLAGS behavior? > > Hmm, yes, that possibility I didn't even consider. Would have > the potential to get away without that admittedly ugly "unary" > assembler macro altogether, though at the price of growing all > instructions rather than just those that have a non-symbolic > and small displacement. Since unlock generally gets inlined, I'm > not certain this additional growth in code size would be > acceptable... > > Please let me know, though before submitting an eventual third > version I'd appreciate knowing especially the first two patches > need further changes in order to get accepted. >
Will look at it today, hopefully. The Syslinux 4.00 release has unfortunately occupied me over the last week-plus.
As far as the "unary" macro is concerned... I have to admit I couldn't even figure out what it was supposed to do. It could definitely use a better comment.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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