Re: [PATCH] Re: sharing mutex between libc stub and libpthread

[Paul Goyette <paul%whooppee.com@localhost>]

On Sat, 23 Feb 2013, Emmanuel Dreyfus wrote:

> Emmanuel Dreyfus <manu%netbsd.org@localhost> wrote:
>
> > Here is a third approach: if program is not linked with -lpthread, the
> > libpthread implementation falls back to libc stubs:
>
> Here is a complete and cleaned up patch:
> http://ftp.espci.fr/shadow/manu/uselibcstub2.patch
>
> I checked it still passes all libpthread tests, and it also passes the
> new dlopen tests I posted earlier. On the performance front, I ran two
> tests to evaluate the hit:
>
> 100 million free(malloc(1024)): slowdown 2%
> without the patch: mean 27.36s, 106 samples, sd 0.48
> with the patch: mean 28.04s, 245 samples, sd 0.25
>
> 100 million gmtime(&now): slowdown not significant
> without the patch: 49,15s, 34 samples, sd 0.35
> with the patch, 48.55s, 51 samples, sf 0.50

By my quick calculations, that's a 1.2% difference.  While not 
substantial, it seems significant to me.


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