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| author | Borislav Petkov | 2010-03-05 17:34:46 +0100 |
|---|---|---|
| committer | H. Peter Anvin | 2010-04-07 00:52:11 +0200 |
| commit | d61931d89be506372d01a90d1755f6d0a9fafe2d (patch) | |
| tree | 652c34238edcb6c558163abc3cd9d6ce7c5f91a5 /lib/Makefile | |
| parent | bitops: Optimize hweight() by making use of compile-time evaluation (diff) | |
| download | kernel-qcow2-linux-d61931d89be506372d01a90d1755f6d0a9fafe2d.tar.gz kernel-qcow2-linux-d61931d89be506372d01a90d1755f6d0a9fafe2d.tar.xz kernel-qcow2-linux-d61931d89be506372d01a90d1755f6d0a9fafe2d.zip | |
x86: Add optimized popcnt variants
Add support for the hardware version of the Hamming weight function,
popcnt, present in CPUs which advertize it under CPUID, Function
0x0000_0001_ECX[23]. On CPUs which don't support it, we fallback to the
default lib/hweight.c sw versions.
A synthetic benchmark comparing popcnt with __sw_hweight64 showed almost
a 3x speedup on a F10h machine.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20100318112015.GC11152@aftab>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'lib/Makefile')
| -rw-r--r-- | lib/Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/Makefile b/lib/Makefile index 2e152aed7198..abe63a8ad143 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -39,7 +39,10 @@ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o obj-$(CONFIG_GENERIC_FIND_LAST_BIT) += find_last_bit.o + +CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS)) obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o + obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o obj-$(CONFIG_BTREE) += btree.o obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o |