[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.

[[email protected]: fixit with gdb]
[[email protected]: Fix KVM too]

Signed-off-by: Jeremy Fitzhardinge <[email protected]>
Signed-off-by: Andi Kleen <[email protected]>
Cc: Ian Campbell <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Acked-by: Zachary Amsden <[email protected]>
Cc: Eric Dumazet <[email protected]>
Signed-off-by: Frederik Deweerdt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions