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| author | Anton Blanchard | 2014-09-16 02:49:14 +0200 |
|---|---|---|
| committer | Michael Ellerman | 2014-09-25 15:14:49 +0200 |
| commit | 423216ed3273dae18c347ce52c5ecc193cfdd4e5 (patch) | |
| tree | 9f1f095dbd57904697dabd2c463e1decace2faa8 /arch/powerpc/platforms | |
| parent | powerpc: Add POWER8 CPU selection (diff) | |
| download | kernel-qcow2-linux-423216ed3273dae18c347ce52c5ecc193cfdd4e5.tar.gz kernel-qcow2-linux-423216ed3273dae18c347ce52c5ecc193cfdd4e5.tar.xz kernel-qcow2-linux-423216ed3273dae18c347ce52c5ecc193cfdd4e5.zip | |
powerpc: Use CONFIG_ARCH_HAS_FAST_MULTIPLIER
I ran some tests to compare hash_64 using shifts and multiplies.
The results:
POWER6: ~2x slower
POWER7: ~2x faster
POWER8: ~2x faster
Now we have a proper config option, select
CONFIG_ARCH_HAS_FAST_MULTIPLIER on POWER7 and POWER8.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/platforms')
| -rw-r--r-- | arch/powerpc/platforms/Kconfig.cputype | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 26703be24cf9..35ae7ec392ec 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -116,10 +116,12 @@ config POWER6_CPU config POWER7_CPU bool "POWER7" depends on PPC_BOOK3S_64 + select ARCH_HAS_FAST_MULTIPLIER config POWER8_CPU bool "POWER8" depends on PPC_BOOK3S_64 + select ARCH_HAS_FAST_MULTIPLIER config E5500_CPU bool "Freescale e5500" |