From: Borislav Petkov <borislav.petkov@amd.com>
Date: Fri, 5 Mar 2010 16:34:46 +0000 (+0100)
Subject: x86: Add optimized popcnt variants
X-Git-Tag: v2.6.35-rc1~512^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d61931d89be506372d01a90d1755f6d0a9fafe2d;p=pandora-kernel.git

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>
---

Reading git-diff-tree failed