Re: BFS vs. mainline scheduler benchmarks and measurements

[Ingo Molnar]

* Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:

> On Thu, Sep 10 2009, Jens Axboe wrote:
> > On Thu, Sep 10 2009, Peter Zijlstra wrote:
> > > On Wed, 2009-09-09 at 14:20 +0200, Jens Axboe wrote:
> > > > 
> > > > One thing I also noticed is that when I have logged in, I 
> > > > run xmodmap manually to load some keymappings (I always tell 
> > > > myself to add this to the log in scripts, but I 
> > > > suspend/resume this laptop for weeks at the time and forget 
> > > > before the next boot). With the stock kernel, xmodmap will 
> > > > halt X updates and take forever to run. With BFS, it 
> > > > returned instantly. As I would expect.
> > > 
> > > Can you provide a little more detail (I'm a xmodmap n00b), how does one
> > > run xmodmap and maybe provide your xmodmap config?
> > 
> > Will do, let me get the notebook and strace time it on both bfs and
> > mainline.
> 
> Here's the result of running perf stat xmodmap .xmodmap-carl on 
> the notebook. I have attached the .xmodmap-carl file, it's pretty 
> simple. I have also attached the output of strace -o foo -f -tt 
> xmodmap .xmodmap-carl when run on 2.6.31-rc9.
> 
> 2.6.31-rc9-bfs210
> 
>  Performance counter stats for 'xmodmap .xmodmap-carl':
> 
>      153.994976  task-clock-msecs         #      0.990 CPUs   (scaled from 99.86%)
>               0  context-switches         #      0.000 M/sec  (scaled from 99.86%)
>               0  CPU-migrations           #      0.000 M/sec  (scaled from 99.86%)
>             315  page-faults              #      0.002 M/sec  (scaled from 99.86%)
>   <not counted>  cycles                  
>   <not counted>  instructions            
>   <not counted>  cache-references        
>   <not counted>  cache-misses            
> 
>     0.155573406  seconds time elapsed

(Side question: what hardware is this - why are there no hw 
counters? Could you post the /proc/cpuinfo?)

> 2.6.31-rc9
> 
>  Performance counter stats for 'xmodmap .xmodmap-carl':
> 
>        8.529265  task-clock-msecs         #      0.001 CPUs 
>              23  context-switches         #      0.003 M/sec
>               1  CPU-migrations           #      0.000 M/sec
>             315  page-faults              #      0.037 M/sec
>   <not counted>  cycles                  
>   <not counted>  instructions            
>   <not counted>  cache-references        
>   <not counted>  cache-misses            
> 
>    11.804293482  seconds time elapsed

Thanks - so we context-switch 23 times - possibly to Xorg. But 11 
seconds is extremely long. Will try to reproduce it.

	Ingo
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