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>
mariux64 · Sep 25, 2014 · 423216e · 423216e
1 parent ff2e466
commit 423216e
Showing 1 changed file with 2 additions and 0 deletions.
diff --git 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"