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Re: [PATCH, AArch64] Add optimized strchr.
- From: OndÅej BÃlka <neleai at seznam dot cz>
- To: Richard Earnshaw <rearnsha at arm dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Wed, 25 Jun 2014 03:42:18 +0200
- Subject: Re: [PATCH, AArch64] Add optimized strchr.
- Authentication-results: sourceware.org; auth=none
- References: <53983583 dot 3040606 at arm dot com>
On Wed, Jun 11, 2014 at 11:54:59AM +0100, Richard Earnshaw wrote:
> Implementation of strchr for AArch64. Speedups taken from micro-bench
> show the improvements relative to the standard C code.
As comments that I made about strchrnul apply also here I will reply
here as strchr is more used.
Our ultimate criteria is if change would improve programs or not, a
benchmarks would give approximation of that.
I have a relatively simple test for that. It just measures a running
time of simple bash script. Could you try several variants with it?
A reason for bash is that most strchr calls on my computer are from
bash. Good implementation makes a difference there, by tweaking old
strchr it on x64 improved performance by around 0.2%.
A benchmark is here, you need to add .so's with different
implementations and then run ./benchmark and wait 10 minutes or so.