Re: [PATCH] scheduler hints

Rick Bressler
2002-06-06T01:14:49Z

> We don't need a scheduler "hint" for this, though. A big loud command
> "bind me to this processor!" would do fine, and in 2.5 we have that:
>
> just have one of the tasks do:
>
> sched_setaffinity(0, sizeof(unsigned long), 1);
> sched_setaffinity(other_guys_pid, sizeof(unsigned long), 1);
>
> and both will be affined to CPU 1.

I think that in some ways they were trying to simplify the code. It is
a bit more complicated to do well from user space. You're talking
dozens to thousands of process pairs, and maybe dozens of CPU's. I
think the idea was that the scheduler has a better idea of what CPU's
are least busy, where to put the processes and indeed should migrate
tasks as necessary. I just does it in pairs. Keep em together is the
idea, rather than keep them in any one specific place, thus the hint.

I note that Gerrit replied also and as I recall he is one of those ex
Sequent guys who really knows this stuff, so I'll bow out in favor of
the experts. :-)

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