[PATCH] Mantaining turnstile aligned to 128 bytes in i386 CPUs

[Nick Evans]

On Tue, 16 Jan 2007 17:51:03 +0100
"Attilio Rao" <attilio at freebsd.org> wrote:

> 2006/7/28, Attilio Rao <attilio at freebsd.org>:
> >
> > After some thinking, I think it's better using init/fini methods
> > (since they hide the sizeof(struct turnstile) with size parameter).
> >
> > Feedbacks and comments are welcome:
> > http://users.gufi.org/~rookie/works/patches/uma_sync_init.diff
> 
> [CC'ed all the interested people]
> 
> Even if a long time is passed I did some benchmarks based on ebizzy tool.
> This program claims to reproduce a real httpd server behaviour and is
> used into the Linux world for benchmarks, AFAIK.
> I think that results of the comparison on this patch is very
> interesting, and I think it worths a commit :)
> I think that results can be even better on a Xeon machine (I had no
> chance to reproduce this on some of these).
> (Results taken in consideration have been measured after some starts,
> in order to minimize caching differences).
> 
> The patch:
> http://users.gufi.org/~rookie/works/patches/ts-sq/ts-sq.diff
> 
> The benchmark results:
> http://users.gufi.org/~rookie/works/patches/ts-sq/ts-sq.benchmark
> 
> The kernel options file:
> http://users.gufi.org/~rookie/works/patches/ts-sq/CURRENT
> 
> For any information, comment, etc. please feel free to contact me.
> 
> Attilio
> 
> 
> -- 
> Peace can only be achieved by understanding - A. Einstein
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Some preliminary results:

PREEMPTION: 4BSD, Quad P3-Xeon, 2GB ram

pre-patch

1.  176.36 real       703.75 user         0.01 sys
2.  176.73 real       704.34 user         0.03 sys
3.  176.49 real       703.72 user         0.04 sys
4.  175.81 real       701.36 user         0.03 sys
5.  176.57 real       700.98 user         0.02 sys

post-patch

1.  179.17 real       714.39 user         0.01 sys
2.  178.33 real       711.50 user         0.04 sys
3.  178.32 real       711.04 user         0.03 sys
4.  177.34 real       707.51 user         0.03 sys
5.  178.25 real       710.17 user         0.03 sys