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Re: [PATCH v3] ARM: Improve armv7 memcpy performance.
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: Will Newton <will dot newton at linaro dot org>
- Cc: "libc-ports at sourceware dot org" <libc-ports at sourceware dot org>, Patch Tracking <patches at linaro dot org>
- Date: Mon, 9 Sep 2013 17:11:36 +0000
- Subject: Re: [PATCH v3] ARM: Improve armv7 memcpy performance.
- Authentication-results: sourceware.org; auth=none
- References: <522D977E dot 2000906 at linaro dot org> <Pine dot LNX dot 4 dot 64 dot 1309091336400 dot 25250 at digraph dot polyomino dot org dot uk> <CANu=DmhpQMif2PVaZQ6eMht_4wJwg75KPFKAt-5xFZm1ZYxCcw at mail dot gmail dot com>
On Mon, 9 Sep 2013, Will Newton wrote:
> I believe the glibc memcpy benchmark is not capable in its present
> form of showing the difference between this version of the code and
> the current one:
>
> 1. The variety of alignments benchmarked is not adequate
> 2. The variability of the benchmark results is quite high (more runs
> required and page allocation issue)
> 3. The output of the benchmark contains no measure of variance
> 4. There is no means of showing graphically the output of the
> benchmark (for subtle differences this is necessary IMO)
Please make sure the wiki todo list
<https://sourceware.org/glibc/wiki/Development_Todo/Master> includes all
these areas for improvement of the benchmarks.
> These are all surmountable problems but I would rather not gate
> acceptance of this code on a satisfactory resolution of the above
> issues. I can provide output from the cortex-strings benchmark quite
> instead though.
If your summary of the benchmarking discussion indicates that the existing
glibc benchmark is not relevant for the cases addressed by the patch, then
it's indeed appropriate to give such results from another benchmark.
--
Joseph S. Myers
joseph@codesourcery.com