Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS]

Willy Tarreau
2007-04-19T13:01:18Z

Hi Ingo,

On Thu, Apr 19, 2007 at 11:01:44AM +0200, Ingo Molnar wrote:
>
> * Willy Tarreau <w@1wt.eu> wrote:
>
> > Good idea. The machine I'm typing from now has 1000 scheddos running
> > at +19, and 12 gears at nice 0. [...]
>
> > From time to time, one of the 12 aligned gears will quickly perform a
> > full quarter of round while others slowly turn by a few degrees. In
> > fact, while I don't know this process's CPU usage pattern, there's
> > something useful in it : it allows me to visually see when process
> > accelerate/decelerate. [...]
>
> cool idea - i have just tried this and it rocks - you can easily see the
> 'nature' of CPU time distribution just via visual feedback. (Is there
> any easy way to start up 12 glxgears fully aligned, or does one always
> have to mouse around to get them into proper position?)

-- Replying quickly, I'm short in time --

You can certainly script it with -geometry. But it is the wrong application
for this matter, because you benchmark X more than glxgears itself. What would
be better is something like a line rotating 360 degrees and doing some short
stuff between each degree, so that X is not much sollicitated, but the CPU
would be spent more on the processes themselves.

Benchmarking interactions between X and multiple clients is a completely
different test IMHO. Glxgears is between those two, making it inappropriate
for scheduler tuning.

Regards,
Willy