Re: [CFT][RFC] HT scheduler

Rusty Russell
2003-12-12T05:28:14Z

In message <3FD7F1B9.5080100@cyberone.com.au> you write:
> http://www.kerneltrap.org/~npiggin/w26/
> Against 2.6.0-test11
>
> This includes the SMT description for P4. Initial results shows comparable
> performance to Ingo's shared runqueue's patch on a dual P4 Xeon.

I'm still not convinced. Sharing runqueues is simple, and in fact
exactly what you want for HT: you want to balance *runqueues*, not
CPUs. In fact, it can be done without a CONFIG_SCHED_SMT addition.

Your patch is more general, more complex, but doesn't actually seem to
buy anything. It puts a general domain structure inside the
scheduler, without putting it anywhere else which wants it (eg. slab
cache balancing). My opinion is either (1) produce a general NUMA
topology which can then be used by the scheduler, or (2) do the
minimal change in the scheduler which makes HT work well.

Note: some of your changes I really like, it's just that I think this
is overkill.

I'll produce a patch so we can have something solid to talk about.

Cheers,
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.