From: Peter Zijlstra <peterz@infradead.org>
To: "Li, Aubrey" <aubrey.li@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Brown, Len" <len.brown@intel.com>,
"alan@linux.intel.com" <alan@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org,
"linux-pm@vger.kernel.org >> Linux PM list"
<linux-pm@vger.kernel.org>
Subject: Re: [RFC/PATCH] PM / Sleep: Timer quiesce in freeze state
Date: Wed, 29 Oct 2014 09:24:32 +0100 [thread overview]
Message-ID: <20141029082432.GV3337@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <5450253B.5020802@linux.intel.com>
On Wed, Oct 29, 2014 at 07:22:35AM +0800, Li, Aubrey wrote:
> On 2014/10/28 16:25, Peter Zijlstra wrote:
> > On Tue, Oct 28, 2014 at 03:52:17PM +0800, Li, Aubrey wrote:
> >
> >> Both clocksource and clockevents are not per-cpu device, why do we need
> >> to run their suspend callback on *each* cpu?
> >
> > Uhm, you mean to say we don't use per-cpu timer lists and per-cpu timer
> > hardware for clockevents then?
> >
>
> From OS level, currently tick device is per-cpu implementation while
> clocksource and clockevent devices are global device.
>
> We already stop tick by clockevents_notify(suspend) on each cpu, that
> addresses per-cpu timer list.
Right, I know. But I was saying I might have confused myself between
events and sources while going through that call chain, thereby
(mistakenly) thinking the source suspend code needed more than the 1
cpu.
Its easy to confuse yourself trying to reverse engineer that opaque
callchain :-)
> And, we already call clocksource_suspend() and clockevents_suspend() in
> timekeeping_suspend() on the tick timer CPU. Yes, we didn't suspend
> per-cpu timer hardware on x86 because x86 does not have lapic timer
> suspend implementation. If we need to implement this, I think we can do
> the cross-CPU calls in clocksource/clockevents suspend(), but I didn't
> see any necessary we need to do this now.
>
> so, I think we are okay now, :)
Right, I tend to agree, we'll find out quickly enough once those
platforms will try this code anyhow ;-)
next prev parent reply other threads:[~2014-10-29 8:24 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-21 15:15 [RFC/PATCH] PM / Sleep: Timer quiesce in freeze state Li, Aubrey
2014-10-24 15:36 ` Peter Zijlstra
2014-10-27 6:27 ` Li, Aubrey
2014-10-27 7:28 ` Peter Zijlstra
2014-10-28 4:32 ` Li, Aubrey
2014-10-28 8:29 ` Peter Zijlstra
2014-10-28 22:46 ` Li, Aubrey
2014-10-29 8:21 ` Peter Zijlstra
2014-10-29 15:09 ` Li, Aubrey
2014-10-27 7:44 ` Peter Zijlstra
2014-10-28 7:52 ` Li, Aubrey
2014-10-28 8:25 ` Peter Zijlstra
2014-10-28 23:22 ` Li, Aubrey
2014-10-29 8:24 ` Peter Zijlstra [this message]
2014-10-30 2:58 ` [PATCH v2] " Li, Aubrey
2014-11-08 2:05 ` Rafael J. Wysocki
2014-11-10 11:49 ` Peter Zijlstra
2014-11-12 21:09 ` Thomas Gleixner
2014-11-13 1:37 ` Peter Zijlstra
2014-11-13 2:20 ` Li, Aubrey
2014-11-13 9:19 ` Thomas Gleixner
2014-11-13 10:50 ` Li, Aubrey
2014-11-13 9:10 ` Thomas Gleixner
2014-11-13 10:47 ` Li, Aubrey
2014-11-13 13:06 ` Thomas Gleixner
2014-11-14 7:58 ` Li, Aubrey
2014-10-28 4:39 ` [RFC/PATCH] " Li, Aubrey
2014-10-28 8:25 ` Peter Zijlstra
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