Re: [PATCH RT 0/6] Linux 3.14.48-rt49-rc1

From: Steven Rostedt
Date: Sat Aug 08 2015 - 19:24:16 EST

On Sat, 8 Aug 2015 19:10:17 -0400
Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> wrote:

> So we took 20 IRQs in 5s, or 4/s ; not quite the 1/s minimum, but definitely not
> the HZ/s we'd get w/o NOHZ_FULL. Re-running it got consistently 18-20 IRQ / 5s.

OK, so NO_HZ_FULL still isn't great on -rt, but this shows that it
keeps disturbances much lower than without it.

Thanks for the report!

-- Steve

> I specifically did NOT unplug and replug cores to "clean" them of tasks; the
> hotplug code just seems to unstable for that from what I've seen in the past,
> and by the looks of the irq counts above, there was no need to either.
> The rootfs was basically a ubu 14.10 server install (no X11/gfx) -- not that
> it should matter - so long as other tasks weren't running on the nohz cores.
> Paul.
> --
> >
> > Enjoy,
> >
> > -- Steve
> >

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