Re: cross-cpu balancing with the new scheduler

[Davide Libenzi]

On Mon, 14 Jan 2002, Manfred Spraul wrote:

> Davide Libenzi wrote:
> >
> > I've a very simple phrase when QA is bugging me with these corner cases :
> >
> > "As Designed"
> >
> > It's much much better than adding code and "Return To QA" :-)
> > I tried priority balancing in BMQS but i still prefer "As Designed" ...
> >
> Another test, now with 4 process (dual cpu):
> #nice -n 19 ./eatcpu&
> #nice -n 19 ./eatcpu&
> #./eatcpu&
> #nice -n -19 ./eatcpu&
>
> And the top output:
> <<<<<<
> 73 processes: 68 sleeping, 5 running, 0 zombie, 0 stopped
> CPU0 states: 100.0% user,  0.0% system, 100.0% nice,  0.0% idle
> CPU1 states: 98.0% user,  2.0% system, 33.0% nice,  0.0% idle
> [snip]
> PID USER     PRI  NI  SIZE  RSS SHARE STAT %CPU %MEM   TIME COMMAND
>  1163 root      39  19   396  396   324 R N  99.5  0.1   0:28 eatcpu
>  1164 root      39  19   396  396   324 R N  33.1  0.1   0:11 eatcpu
>  1165 root      39   0   396  396   324 R    33.1  0.1   0:07 eatcpu
>  1166 root      39 -19   396  396   324 R <  31.3  0.1   0:06 eatcpu
>  1168 manfred    1   0   980  976   768 R     2.7  0.2   0:00 top
> [snip]
>
> The niced process still has it's own cpu, and the "nice -19" process has
> 33% of the second cpu.
>
> IMHO that's buggy. 4 running process, 1 on cpu0, 3 on cpu1.

Yes, a long run with 3:1 is no more "As Designed" :-)

- Davide