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authorJeremy Fitzhardinge <jeremy@goop.org>2007-02-13 07:26:20 -0500
committerAndi Kleen <andi@basil.nowhere.org>2007-02-13 07:26:20 -0500
commit464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 (patch)
tree536d8a92976e675b484b35dec88d40c97fab8ac8 /include/asm-i386/elf.h
parent54413927f022292aeccadd268fbf1c0b42129945 (diff)
[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 <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Ian Campbell <Ian.Campbell@XenSource.com> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Zachary Amsden <zach@vmware.com> Cc: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
Diffstat (limited to 'include/asm-i386/elf.h')
-rw-r--r--include/asm-i386/elf.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h
index 369035dfe4b6..8d33c9bb7c1c 100644
--- a/include/asm-i386/elf.h
+++ b/include/asm-i386/elf.h
@@ -90,8 +90,8 @@ typedef struct user_fxsr_struct elf_fpxregset_t;
90 pr_reg[6] = regs->eax; \ 90 pr_reg[6] = regs->eax; \
91 pr_reg[7] = regs->xds; \ 91 pr_reg[7] = regs->xds; \
92 pr_reg[8] = regs->xes; \ 92 pr_reg[8] = regs->xes; \
93 savesegment(fs,pr_reg[9]); \ 93 pr_reg[9] = regs->xfs; \
94 pr_reg[10] = regs->xgs; \ 94 savesegment(gs,pr_reg[10]); \
95 pr_reg[11] = regs->orig_eax; \ 95 pr_reg[11] = regs->orig_eax; \
96 pr_reg[12] = regs->eip; \ 96 pr_reg[12] = regs->eip; \
97 pr_reg[13] = regs->xcs; \ 97 pr_reg[13] = regs->xcs; \