Messages in this thread |  | | | Subject | Re: [2.6.16-mm1 patch] throttling tree patches | | From | Mike Galbraith <> | | Date | Sat, 25 Mar 2006 06:11:59 +0100 |
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On Sat, 2006-03-25 at 11:37 +1100, Peter Williams wrote: > Mike Galbraith wrote: > > Greetings, > > > > I've broken down my throttling tree into 6 patches, which I'll send as > > replies to this start-point. > > > > Patch 1/6 > > > > Ignore timewarps caused by SMP timestamp rounding. Also, don't stamp a > > task with a computed timestamp, stamp with the already called clock. > > > > Signed-off-by: Mike Galbraith <efault@gmx.de> > > > > --- linux-2.6.16-mm1/kernel/sched.c.org 2006-03-23 15:01:41.000000000 +0100 > > +++ linux-2.6.16-mm1/kernel/sched.c 2006-03-23 15:02:25.000000000 +0100 > > @@ -805,6 +805,16 @@ > > unsigned long long __sleep_time = now - p->timestamp; > > unsigned long sleep_time; > > > > + /* > > + * On SMP systems, a task can go to sleep on one CPU and > > + * wake up on another. When this happens, the timestamp > > + * is rounded to the nearest tick, > > Is this true? There's no rounding that I can see.
Instrumenting it looked the same as rounding down, putting now in the past was the result.
> Of course, that doesn't mean that this chunk of code isn't required just > that the comment is misleading.
I'm not attached to the comment.
-Mike
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