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Re: [PATCH] sysdeps/arm/armv7/multiarch/memcpy_impl.S: Improve performance.
- From: Will Newton <will dot newton at linaro dot org>
- To: "Carlos O'Donell" <carlos at redhat dot com>
- Cc: "libc-ports at sourceware dot org" <libc-ports at sourceware dot org>, Patch Tracking <patches at linaro dot org>
- Date: Fri, 30 Aug 2013 19:48:32 +0100
- Subject: Re: [PATCH] sysdeps/arm/armv7/multiarch/memcpy_impl.S: Improve performance.
- Authentication-results: sourceware.org; auth=none
- References: <520894D5 dot 7060207 at linaro dot org> <CANu=DmiBHoymFKTvaW_VsdhWZEYwkfViz1tTeRgj7H80f0FntA at mail dot gmail dot com> <5220D30B dot 9080306 at redhat dot com>
On 30 August 2013 18:14, Carlos O'Donell <carlos@redhat.com> wrote:
Hi Carlos,
>>> A small change to the entry to the aligned copy loop improves
>>> performance slightly on A9 and A15 cores for certain copies.
>>>
>>> ports/ChangeLog.arm:
>>>
>>> 2013-08-07 Will Newton <will.newton@linaro.org>
>>>
>>> * sysdeps/arm/armv7/multiarch/memcpy_impl.S: Tighten check
>>> on entry to aligned copy loop for improved performance.
>>> ---
>>> ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> Ping?
>
> How did you test the performance?
>
> glibc has a performance microbenchmark, did you use that?
No, I used the cortex-strings package developed by Linaro for
benchmarking various string functions against one another[1].
I haven't checked the glibc benchmarks but I'll look into that. It's
quite a specific case that shows the problem so it may not be obvious
which one is better however.
[1] https://launchpad.net/cortex-strings
--
Will Newton
Toolchain Working Group, Linaro