From: soren.brinkmann@xilinx.com (Sören Brinkmann)
To: linux-arm-kernel@lists.infradead.org
Subject: Dropping "depends on SMP" for HAVE_ARM_TWD -- take 2
Date: Mon, 5 Oct 2015 08:13:03 -0700 [thread overview]
Message-ID: <20151005151303.GJ26391@xsjsorenbubuntu> (raw)
In-Reply-To: <20151005114940.GA4448@afzalpc>
On Mon, 2015-10-05 at 05:19PM +0530, Afzal Mohammed wrote:
> Hi,
>
> On Sun, Oct 04, 2015 at 10:46:52PM -0700, S?ren Brinkmann wrote:
> > On Sat, 2015-10-03 at 11:12AM +0100, Marc Zyngier wrote:
>
> > > Indeed, I cannot see any code that does that in the GT driver. But if
> > > you have an A9 MP, you probably want to stick to TWD, which gives you a
> > > per-cpu timer instead of a global timer that will require IPIs to other
> > > CPUs.
> >
> > I think the TWD only provides a clock_event device. Clocksource and
> > schedclock would have to be provided by something else.
>
> If no clocksource, sched clock is provided, default jiffies based ones
> would be sufficient for single core, no ?, though not a preferred one.
Yes that is correct. My point was more, that twd+cpufreq is a rather
easy case since it doesn't provide a clocksource/schedclock. A driver
that provides those needs quite some more work if it depends on the CPU
frequency and needs to be usable with cpufreq.
S?ren
next prev parent reply other threads:[~2015-10-05 15:13 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 9:52 Dropping "depends on SMP" for HAVE_ARM_TWD -- take 2 Mason
2015-10-02 13:24 ` Mason
2015-10-02 18:02 ` Stephen Boyd
2015-10-02 18:48 ` Felipe Balbi
2015-10-02 18:55 ` Russell King - ARM Linux
2015-10-02 19:18 ` Felipe Balbi
2015-10-02 18:50 ` Mason
2015-10-02 19:41 ` Stephen Boyd
2015-10-02 23:34 ` Måns Rullgård
2015-10-03 9:32 ` Marc Zyngier
2015-10-03 9:49 ` Mason
2015-10-03 10:12 ` Marc Zyngier
2015-10-05 5:46 ` Sören Brinkmann
2015-10-05 7:38 ` Mason
2015-10-05 9:03 ` Linus Walleij
2015-10-05 11:49 ` Afzal Mohammed
2015-10-05 15:13 ` Sören Brinkmann [this message]
2015-10-05 15:25 ` Russell King - ARM Linux
2015-10-06 8:21 ` Mason
2015-10-06 19:38 ` Stephen Boyd
2015-10-06 20:01 ` Felipe Balbi
2015-10-06 20:17 ` Mason
2015-10-06 21:05 ` Felipe Balbi
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