lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

x86: Add optimized popcnt variants

Browse Source 
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>
This commit is contained in:
Borislav Petkov
2010-03-05 17:34:46 +01:00
committed by H. Peter Anvin
parent 1527bc8b92
commit d61931d89b
8 changed files with 108 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
scripts/Makefile.lib
View File

@ -245,3 +245,7 @@ quiet_cmd_lzo = LZO $@
cmd_lzo = (cat $(filter-out FORCE,$^) | \
lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
(rm -f $@ ; false)
# misc stuff
# ---------------------------------------------------------------------------
quote:="