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SubjectRe: [PATCH] x86: use cpufreq_quick_get() for /proc/cpuinfo "cpu MHz" again
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On Wednesday, November 15, 2017 1:06:12 AM CET Linus Torvalds wrote:
> On Tue, Nov 14, 2017 at 4:04 PM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> > On Tue, Nov 14, 2017 at 3:53 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> >> Current head + Raphaels patch:
> >>
> >> real 0m0.029s
> >> user 0m0.000s
> >> sys 0m0.010s
> >>
> >> So that patch is actually slower.
> >
> > Oh it definitely is expected to be slower, because it does the IPI to
> > all the cores and actually gets their frequency right.
> >
> > It was the old one that we had to revert (because it did so
> > sequentially) that was really bad, and took something like 2+ seconds
> > on Ingo's 160-core thing, iirc.
>
> Looked it up. Ingo's machine "only" had 120 cores, and he said
>
> fomalhaut:~> time cat /proc/cpuinfo >/dev/null
> real 0m2.689s
>
> for the bad serial case, so yeah, it looks "a bit" better than it was ;)

OK, so may I queue it up?

I don't think I can get that to work substantially faster anyway ...

Thanks,
Rafael

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