[GIT PULL] scalable TWD localtimer

Santosh Shilimkar santosh.shilimkar at ti.com
Fri Jun 3 01:26:29 EDT 2011


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.


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