From: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
To: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
John Stultz <john.stultz@linaro.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCHv7 01/11] clockevents: Prefer CPU local devices over global devices
Date: Thu, 13 Jun 2013 13:16:35 -0700 [thread overview]
Message-ID: <999cad28-cd11-489c-91d1-012ffa03b21c@CO9EHSMHS019.ehs.local> (raw)
In-Reply-To: <20130613183950.GA32061@codeaurora.org>
On Thu, Jun 13, 2013 at 11:39:50AM -0700, Stephen Boyd wrote:
> On 06/13, Thomas Gleixner wrote:
> > On Thu, 13 Jun 2013, Daniel Lezcano wrote:
> > > I prefer Thomas to have a look at it and ack it. I changed Cc to To for
> > > Thomas.
> >
> > The patch does not apply on tip timers/core. The code has been
> > reworked a month ago. Please work against tip timers/core. That's
> > where this stuff ends up.
> >
>
> Ah, I thought your patch series had stalled. Here is a refreshed
> patch. Every other patch in this series applies cleanly to tip
> timers/core so I don't want to resend them again unless
> absolutely necessary.
>
> -----8<-----
> Subject: [PATCH v8] clockevents: Prefer CPU local devices over global devices
>
> On an SMP system with only one global clockevent and a dummy
> clockevent per CPU we run into problems. We want the dummy
> clockevents to be registered as the per CPU tick devices, but
> we can only achieve that if we register the dummy clockevents
> before the global clockevent or if we artificially inflate the
> rating of the dummy clockevents to be higher than the rating
> of the global clockevent. Failure to do so leads to boot
> hangs when the dummy timers are registered on all other CPUs
> besides the CPU that accepted the global clockevent as its tick
> device and there is no broadcast timer to poke the dummy
> devices.
>
> If we're registering multiple clockevents and one clockevent is
> global and the other is local to a particular CPU we should
> choose to use the local clockevent regardless of the rating of
> the device. This way, if the clockevent is a dummy it will take
> the tick device duty as long as there isn't a higher rated tick
> device and any global clockevent will be bumped out into
> broadcast mode, fixing the problem described above.
>
> Reported-by: Mark Rutland <mark.rutland@arm.com>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
I retested my case on tip/timers/core with the same results.
Sören
next prev parent reply other threads:[~2013-06-13 20:16 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-03 20:33 [PATCHv7 00/11] Remove ARM local timer API Stephen Boyd
2013-06-03 20:33 ` [PATCHv7 01/11] clockevents: Prefer CPU local devices over global devices Stephen Boyd
2013-06-06 15:12 ` Daniel Lezcano
2013-06-06 18:04 ` Stephen Boyd
2013-06-06 22:30 ` Daniel Lezcano
2013-06-06 22:38 ` Stephen Boyd
2013-06-12 21:44 ` Stephen Boyd
2013-06-13 9:33 ` Daniel Lezcano
2013-06-13 13:15 ` Thomas Gleixner
2013-06-13 18:39 ` Stephen Boyd
2013-06-13 20:16 ` Sören Brinkmann [this message]
2013-06-18 10:22 ` Mark Rutland
2013-06-19 16:30 ` Stephen Boyd
2013-06-21 17:07 ` Stephen Boyd
2013-06-24 20:07 ` Stephen Boyd
2013-06-24 20:30 ` [tip:timers/core] " tip-bot for Stephen Boyd
2013-06-03 20:33 ` [PATCHv7 02/11] clocksource: add generic dummy timer driver Stephen Boyd
2013-06-06 16:23 ` Daniel Lezcano
2013-06-24 20:30 ` [tip:timers/core] clocksource: Add " tip-bot for Mark Rutland
2013-06-03 20:33 ` [PATCHv7 03/11] ARM: smp: Remove duplicate dummy timer implementation Stephen Boyd
2013-06-03 20:33 ` [PATCHv7 04/11] ARM: smp_twd: Divorce smp_twd from local timer API Stephen Boyd
2013-06-03 20:33 ` [PATCHv7 05/11] ARM: OMAP2+: Divorce " Stephen Boyd
2013-06-03 20:33 ` [PATCHv7 06/11] ARM: EXYNOS4: Divorce mct " Stephen Boyd
2013-06-03 20:33 ` [PATCHv7 07/11] ARM: PRIMA2: Divorce timer-marco " Stephen Boyd
2013-06-03 20:33 ` [PATCHv7 08/11] ARM: msm: Divorce msm_timer " Stephen Boyd
2013-06-03 20:34 ` [PATCHv7 09/11] clocksource: time-armada-370-xp: Fix sparse warning Stephen Boyd
2013-06-03 20:34 ` [PATCHv7 10/11] clocksource: time-armada-370-xp: Divorce from local timer API Stephen Boyd
2013-06-03 20:34 ` [PATCHv7 11/11] ARM: smp: Remove " Stephen Boyd
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