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Re: [PATCH] powerpc64: Add POWER8 strnlen
- From: Carlos Eduardo Seo <cseo at linux dot vnet dot ibm dot com>
- To: Wainer dos Santos Moschetta <wainersm at linux dot vnet dot ibm dot com>
- Cc: <libc-alpha at sourceware dot org>
- Date: Thu, 23 Mar 2017 18:14:20 -0300
- Subject: Re: [PATCH] powerpc64: Add POWER8 strnlen
- Authentication-results: sourceware.org; auth=none
- References: <20170321201144.10513-1-wainersm@linux.vnet.ibm.com>
On 3/21/17, 5:11 PM, "Wainer dos Santos Moschetta" <libc-alpha-owner@sourceware.org on behalf of wainersm@linux.vnet.ibm.com> wrote:
Added strnlen POWER8 otimized for long strings. It delivers
same performance as POWER7 implementation for short strings.
This takes advantage of reasonably performing unaligned loads
and bit permutes to check the first 1-16 bytes until
quadword aligned, then checks in 64 bytes strides until unsafe,
then 16 bytes, truncating the count if need be.
Likewise, the POWER7 code is recycled for less than 32 bytes strings.
Tested on ppc64 and ppc64le.
LGTM
--
Carlos Eduardo Seo
Software Engineer - Linux on Power Toolchain
cseo@linux.vnet.ibm.com