Re: [patch] CFS scheduler, -v8

Ingo Molnar
2007-05-02T10:06:58Z

* Balbir Singh <balbir@linux.vnet.ibm.com> wrote:

> With -v7 I would run the n/n+1 test. Basically on a system with n
> cpus, I would run n+1 tasks and see how their load is distributed. I
> usually find that the last two tasks would get stuck on one CPU on the
> system and would get half the cpu time as their other peers. I think
> this issue has been around for long even before CFS. But while I was
> investigating that, I found that with -v8, all the n+1 tasks are stuck
> on the same cpu.

i believe this problem is specific to powerpc - load is distributed fine
on i686/x86_64 and your sched_debug shows a cpu_load[0] == 0 on CPU#2
which is 'impossible'. (I sent a few suggestions off-Cc about how to
debug this.)

Ingo