diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-02-13 13:26:20 +0100 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-02-13 13:26:20 +0100 |
| commit | 464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 (patch) | |
| tree | 536d8a92976e675b484b35dec88d40c97fab8ac8 /arch/i386/kernel/kprobes.c | |
| parent | 54413927f022292aeccadd268fbf1c0b42129945 (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 'arch/i386/kernel/kprobes.c')
| -rw-r--r-- | arch/i386/kernel/kprobes.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c index af1d5334499..b85cfa3ce1d 100644 --- a/arch/i386/kernel/kprobes.c +++ b/arch/i386/kernel/kprobes.c @@ -363,7 +363,7 @@ no_kprobe: " pushf\n" /* skip cs, eip, orig_eax */ " subl $12, %esp\n" - " pushl %gs\n" + " pushl %fs\n" " pushl %ds\n" " pushl %es\n" " pushl %eax\n" @@ -387,7 +387,7 @@ no_kprobe: " popl %edi\n" " popl %ebp\n" " popl %eax\n" - /* skip eip, orig_eax, es, ds, gs */ + /* skip eip, orig_eax, es, ds, fs */ " addl $20, %esp\n" " popf\n" " ret\n"); |