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From: santosh.shilimkar@ti.com (Santosh Shilimkar)
To: linux-arm-kernel@lists.infradead.org
Subject: [GIT PULL] scalable TWD localtimer
Date: Fri, 03 Jun 2011 10:56:29 +0530	[thread overview]
Message-ID: <4DE87085.1090901@ti.com> (raw)
In-Reply-To: <BANLkTik0TVpfax1Fe8c_6A9SFUNzfDbxyw@mail.gmail.com>

Linus,

On 6/3/2011 3:31 AM, Linus Walleij wrote:
> Hi Russell,
>
> please consider pulling this for the -rc series since I see this as a
> horrible bug that Thomas just fixed the infrastructure to properly
> counter the week before the merge window.
>
> You probably know the story but basically there is one clockline
> into the ARM-supplied MPCore thing, and it inevitably also clocks
> the TWD. Sadly that includes the localtimer, which will make all
> clockevents scale in both directions, firing too late or too early
> as compared to desired wall-clock time (or system clocksource) as
> the clock speed of the core is changed. Right now there is no
> compensation whatsoever for this so to run the system reliably
> on v3.0-rc1, cpufreq has to be disabled.
>
> Thomas and Colin did the grunt work, I added a scaling smp_twd
> clock reflecting the Ux500 cpufreq changes, and now it is rock solid
> as far as I can tell.
>
Hope the pull is already not done. If not I would like to submit the
OMAP clock change as well along with this series and may be Colin might
want to do the same for Tegra.

Regards
Santosh

  reply	other threads:[~2011-06-03  5:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-02 22:01 [GIT PULL] scalable TWD localtimer Linus Walleij
2011-06-03  5:26 ` Santosh Shilimkar [this message]
2011-06-03  6:16   ` Colin Cross
2011-06-03  6:21     ` Santosh Shilimkar

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