Re: [Lse-tech] [patch] sched-domain cleanups, sched-2.6.5-rc2-mm2-A3

Rick Lindsley
2004-03-30T01:27:56Z

This looks very cool. Very comprehensive. Have you got any
plans to intergrate it with sched_domains (so for example,
you can see stats for each domain)?

Yes -- ideally we can add some stats to domains too, so we can tell
(for example) how often it is adjusting rebalance intervals, or how many
processes are moved as a result of each domain's policy, etc. Every time
I add another counter I cringe a bit, because we don't want to impose
overhead in the scheduler. But so far, using per-cpu data, utilizing
runqueue locking when it's in use, and accepting minor inaccuracies that
may result from the remaining cases, seems to be yielding a pretty good
picture of things without imposing a measurable load.

If you want to start using it yourself, I'm open to feedback. I have patches
for major releases at

http://oss.software.ibm.com/linux/patches/?patch_id=730

and a host of smaller releases (like rc2-mm5) at eaglet:

http://eaglet.rain.com/rick/linux/schedstat/

If you're feeling *really* lucky I have a handful of useful but often
ungeneralized tools I can share, like the the ones that made that web
page.

Rick