Messages in this thread | | | Date | Fri, 8 Jun 2012 01:07:05 -0700 | From | Anton Vorontsov <> | Subject | Re: [PATCH 2/5] vmevent: Convert from deferred timer to deferred work |
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On Fri, Jun 08, 2012 at 10:03:24AM +0300, Pekka Enberg wrote: > On Fri, Jun 8, 2012 at 9:58 AM, Anton Vorontsov > <anton.vorontsov@linaro.org> wrote: > > If you're saying that we should set up a timer in the userland and > > constantly read /proc/vmstat, then we will cause CPU wake up > > every 100ms, which is not acceptable. Well, we can try to introduce > > deferrable timers for the userspace. But then it would still add > > a lot more overhead for our task, as this solution adds other two > > context switches to read and parse /proc/vmstat. I guess this is > > not a show-stopper though, so we can discuss this. > > > > Leonid, Pekka, what do you think about the idea? > > That's exactly the kind of half-assed ABI that lead to people > inventing out-of-tree lowmem notifiers in the first place.
:-)
Well, at least powersaving-wise, the solution w/ userland deferred timers would be much better then just looping over /proc/vmstat each 100ms, and it is comparable to vmevent. Not pretty, but still would work.
> I'd be more interested to know what people think of Minchan's that > gets rid of vmstat sampling.
I answered to Minchan's post. The thing is that Minchan's idea is not a substitution for vmevent. To me it seems like a shrinker w/ some pre-filter.
Thanks,
-- Anton Vorontsov Email: cbouatmailru@gmail.com
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