From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org
Cc: mikey@neuling.org
Subject: Re: powerpc/opal: Wake up kopald polling thread before waiting for events
Date: Mon, 04 Jul 2016 17:50:40 +1000 [thread overview]
Message-ID: <1467618640.13965.3.camel@kernel.crashing.org> (raw)
In-Reply-To: <3rjc8Z6nDPz9sXx@ozlabs.org>
On Mon, 2016-07-04 at 16:11 +1000, Michael Ellerman wrote:
> On Mon, 2016-04-07 at 04:51:44 UTC, Benjamin Herrenschmidt wrote:
> > On some environments (prototype machines, some simulators, etc...)
> > there is no functional interrupt source to signal completion, so
> > we rely on the fairly slow OPAL heartbeat.
> >
> > In a number of cases, the calls complete very quickly or even
> > immediately. We've observed that it helps a lot to wakeup the OPAL
> > heartbeat thread before waiting for event in those cases, it will
> > call OPAL immediately to collect completions for anything that
> > finished fast enough.
>
> Any performance/jitter impact on normal systems?
Not that I can think of.
Cheers,
Ben.
next prev parent reply other threads:[~2016-07-04 7:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-04 4:51 [PATCH] powerpc/opal: Wake up kopald polling thread before waiting for events Benjamin Herrenschmidt
2016-07-04 6:11 ` Michael Ellerman
2016-07-04 7:50 ` Benjamin Herrenschmidt [this message]
2016-07-04 9:45 ` [PATCH] " Michael Neuling
2016-07-11 10:19 ` Michael Ellerman
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