[PATCH] PowerPC:strrchr() optimization

[Ondřej Bílka]

On Mon, Feb 10, 2014 at 11:43:09AM +0530, Rajalakshmi Srinivasaraghavan wrote:
> Hi All
> 
> This patch optimizes strrchr() for ppc64. I have attached the benchtest
> output to show the performance improvement.This is coded with strchr.S as reference and uses
> cmpb instruction for speed improvement.

Hi, 

There is one thing to check as strrchr could be genericaly implemented
by other primitives.

I send a patch for that, could you check how does that compare?

https://sourceware.org/ml/libc-alpha/2013-10/msg00201.html

Benchmarking strrchr is bit tricky as performance depends on frequency
of searched character. I did profiling and most common usecase is
finding trailing / in pathnames. Typically a result is between 10 and 20
characters from start. See following for more statistic.

http://kam.mff.cuni.cz/~ondra/benchmark_string/i7_ivy_bridge/strrchr_profile/results_gcc/result.html