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| author | Anton Blanchard <anton@samba.org> | 2015-10-29 11:43:53 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2015-12-01 13:52:24 +1100 |
| commit | 07e45c120c9c61b792be62182b0a8f706ee2ab24 (patch) | |
| tree | 5936a948a53b1bca0dad87eaa5c23648527a8970 /arch/powerpc/include/asm/processor.h | |
| parent | powerpc/64: Include KVM guest test in all interrupt vectors (diff) | |
| download | linux-07e45c120c9c61b792be62182b0a8f706ee2ab24.tar.gz linux-07e45c120c9c61b792be62182b0a8f706ee2ab24.zip | |
powerpc: Don't disable kernel FP/VMX/VSX MSR bits on context switch
Writing the MSR is slow, so we want to avoid it whenever possible.
A subsequent patch will add a debug option that strictly manages the
FP/VMX/VSX unavailable bits. For now just remove it, matching what
we do in other areas of the kernel (eg enable_kernel_altivec()).
A context switch microbenchmark using yield():
http://ozlabs.org/~anton/junkcode/context_switch2.c
./context_switch2 --test=yield --fp 0 0
shows an improvement of almost 3% on POWER8.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/processor.h')
0 files changed, 0 insertions, 0 deletions