Re: [PATCH] Staircase scheduler v7.4

[kernel]

Quoting Willy Tarreau <willy@xxxxxxxxx>:

> Hi Con,
> 
> although I was one of those who complained a lot about the 2.6 scheduler,
> and still don't use it because of its sluggishness under X11, I'm impressed
> by your work here. I've tried the good old test which was *very* sluggish
> on a vanilla 2.6 :

Well I can take the blame for that since I tuned it. I tried very hard to do it
without changing the overall design :\

> 
> # for i in $(seq 1 20); do xterm -e sh -c "while :; do locate /;done" & done
> 
> It opens 20 xterms constantly listing my slocate database (vmstat shows
> no I/O).
> 
> Under vanilla 2.6 (up to 2.6.4 at least), some of these xterms would freeze
> for up to about 10 seconds IIRC during redrawing, with incomplete lines,
> etc...
> This still happens with your patch and /p/s/k/interactive=0, but to a lesser
> extent it seems. But it does not happen anymore with interactive=1, hence
> the
> progress !
> 
> However, you warned us that the nice parameter was very sensible. Indeed,
> it *is* ! When my window manager (ctwm, very light) is at 0, just like the
> script above, the windows appear slowly and irregularly on the screen,
> but this takes no more than 15s, during which windows get no title, then
> suddenly they get everything right. If I renice the WM at +1, I see no
> more than 5 windows on the screen with no decoration at all, and then I
> cannot even change the focus to another one anymore. Then, as soon as I
> change the WM's nice value to -1, suddenly all remaining windows appear
> with their title. The same is true if I start the script with the WM at
> -1 initially. It's just as if the nice value was directly used as the
> priority in a queue.
> 
> Oh and BTW, this is an SMP box (dual athlon).
> 
> Well, I see there is some very good progress ! Please keep up the good
> work !

Thanks! I'll try my best.

Con


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