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(parent: 9319c6c) | patch
powerpc: Use CONFIG_ARCH_HAS_FAST_MULTIPLIER
authorAnton Blanchard <anton@samba.org>
Tue, 16 Sep 2014 00:49:14 +0000 (10:49 +1000)
committerMichael Ellerman <mpe@ellerman.id.au>
Thu, 25 Sep 2014 13:14:49 +0000 (23:14 +1000)
commit4ea0f592e9923f9fd1f7511d1d2167e560d20b5d
tree9f1f095dbd57904697dabd2c463e1decace2faa8tree | snapshot
parent9319c6c571cb9dd4d8b4c28f824d64cb317aa56acommit | diff
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>
arch/powerpc/platforms/Kconfig.cputype diff | blob | history
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