[RFC] Porting string performance tests into benchtests

[Ondřej Bílka]

On Wed, Apr 03, 2013 at 11:40:42PM -0400, David Miller wrote:
> From: Siddhesh Poyarekar <siddhesh@redhat.com>
> Date: Thu, 4 Apr 2013 09:07:19 +0530
> 
> > On Wed, Apr 03, 2013 at 12:35:22PM -0400, David Miller wrote:
> >> 
> >> I strongly perfer the raw cpu cycle counter read.
> > 
> > Could you elaborate on that?  Is it just a personal preference or is
> > some aspect of my argument in favour of clock_gettime incorrect or
> > irrelevant?
> 
> I really want to see on the cpu cycle level whether the changes I make
> to the pre-loop and post-loop code make any difference.
>
Which as for str* majority of time is spend on pre/loop code is most
important to measure.
 
> And on sparc chips I don't have the issues that can make the cpu cycle
> counter inaccurate or less usable as a timing mechanism.

Other benefit is that you can rapidly vary implementations. This mostly
eliminate biases caused by cpu frequency switching etc.