[GIT PULL] omap changes for v2.6.39 merge window

Catalin Marinas catalin.marinas at arm.com
Mon Apr 4 07:03:42 EDT 2011

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.


More information about the linux-arm-kernel mailing list