Re: [tip:core/rcu] Revert "rcu: Decrease memory-barrier usage basedon semi-formal proof"

From: Ingo Molnar
Date: Wed May 25 2011 - 03:18:37 EST



* Yinghai Lu <yinghai@xxxxxxxxxx> wrote:

> >> got:
> >>
> >> [ 32.803704] cpu_dev_init done
> >> [ 99.171292] memory_dev_init done
> >
> > So the difference between these two is noise, I hope. Adding a static
> > inline function that is not used should not have an effect on performance.
> > Still, the difference between 6 seconds and 60 seconds rises far above
> > this noise level, so the big differences are likely quite real.
>
> could be softirq to kthread change...

Softirq processing can be pretty nondeterministic (for example there's no
guarantee that we process all softirqs) - but kthreads ought to be pretty
deterministic. Weird.

Thanks,

Ingo
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