Messages in this thread | | | Subject | Re: [GIT PULL] omap changes for v2.6.39 merge window | From | Catalin Marinas <> | Date | Mon, 04 Apr 2011 12:03:42 +0100 |
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On Mon, 2011-04-04 at 01:59 +0100, Arnd Bergmann wrote: > On Sunday 03 April 2011, Russell King - ARM Linux wrote: > > Then there's those which change the cs->read function pointer at runtime, ... > > and those which share that pointer with their sched_clock() implementation. > > Abstracting sched_clock() to be run-time selected is something that > needs to be taken care of. Maybe we could have a generic sched_clock > implementation that is written on top of clocksource instead of jiffies, > and always select that on architectures that have a decent clocksource.
On Cortex-A15 with the virtualisation extensions and architected timers the clocksource is implemented using a physical counter (as we want wall-clock timing). But for sched_clock() we may want to use a virtual counter (which is basically an offset from the physical one, set by the hypervisor during guest OS switching). Marc already posted some patches for this.
-- Catalin
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