From 464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 13 Feb 2007 13:26:20 +0100 Subject: [PATCH] i386: Convert i386 PDA code to use %fs Convert the PDA code to use %fs rather than %gs as the segment for per-processor data. This is because some processors show a small but measurable performance gain for reloading a NULL segment selector (as %fs generally is in user-space) versus a non-NULL one (as %gs generally is). On modern processors the difference is very small, perhaps undetectable. Some old AMD "K6 3D+" processors are noticably slower when %fs is used rather than %gs; I have no idea why this might be, but I think they're sufficiently rare that it doesn't matter much. This patch also fixes the math emulator, which had not been adjusted to match the changed struct pt_regs. [frederik.deweerdt@gmail.com: fixit with gdb] [mingo@elte.hu: Fix KVM too] Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Ian Campbell Acked-by: Ingo Molnar Acked-by: Zachary Amsden Cc: Eric Dumazet Signed-off-by: Frederik Deweerdt Signed-off-by: Andrew Morton --- include/asm-i386/ptrace.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/asm-i386/ptrace.h') diff --git a/include/asm-i386/ptrace.h b/include/asm-i386/ptrace.h index bdbc894339b..1646996c73d 100644 --- a/include/asm-i386/ptrace.h +++ b/include/asm-i386/ptrace.h @@ -16,8 +16,8 @@ struct pt_regs { long eax; int xds; int xes; - /* int xfs; */ - int xgs; + int xfs; + /* int xgs; */ long orig_eax; long eip; int xcs; -- cgit v1.2.3-70-g09d2