[lkml]   [2007]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] sched: avoid large irq-latencies in smp-balancing

On Wed, 2007-11-07 at 17:10 -0500, Steven Rostedt wrote:
> >
> > It would be nice if sched_nr_migrate didn't exist, really. It's hard to
> > imagine anyone wanting to tweak it, apart from developers.
> I'm not so sure about that. It is a tunable for RT. That is we can tweak
> this value to be smaller if we don't like the latencies it gives us.
> This is one of those things that sacrifices performance for latency.
> The higher the number, the better it can spread tasks around, but it
> also causes large latencies.
> I've just included this patch into and it brought down an
> unbounded latency to just 42us. (previously we got into the
> milliseconds!).
> Perhaps when this feature matures, we can come to a good defined value
> that would be good for all. But until then, I recommend keeping this a
> tunable.

Why not use the latency-expectation infrastructure?

Iterate under lock until (or before...) the system global latency is

- Eric

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-11-08 01:27    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean