Re: [PATCH 2.6.20-rc4 0/4] futexes functionalities and improvements

[Pierre Peiffer <pierre.peiffer@bull.net>]

Hi,

Ingo Molnar a écrit :
> yeah. As an alternative, it might be a good idea to pthread-ify 
> hackbench.c - that should replicate the Volano workload pretty 
> accurately. I've attached hackbench.c. (it's process based right now, so 
> it wont trigger contended futex ops)

Ok, thanks. I've adapted your test, Ingo, and do some measures. (I've only 
replaced fork with pthread_create, I didn't use condvar or barrier for the first 
synchronization).
The modified hackbench is available here:

http://www.bullopensource.org/posix/pi-futex/hackbench_pth.c

I've run this bench 1000 times with pipe and 800 groups.
Here are the results:

Test1 - with simple list (i.e. without any futex patches)
=========================================================
Iterations=1000
Latency (s)      min      max      avg      stddev
                 26.67    27.89    27.14        0.19

Test2 - with plist (i.e. with only patch 1/4 as is)
===================================================
Iterations=1000
Latency (s)      min      max      avg      stddev
                 26.87    28.18    27.30        0.18

Test3 - with plist but all SHED_OTHER registered
         with the same priority (MAX_RT_PRIO)
(i.e. with modified patch 1/4, patch not yet posted here)
=========================================================
Iterations=1000
Latency (s)      min      max      avg      stddev
                 26.74    27.84    27.16        0.18


-- 
Pierre