From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Mon, 04 Apr 2011 12:03:42 +0100 Subject: [GIT PULL] omap changes for v2.6.39 merge window In-Reply-To: <201104040259.26601.arnd@arndb.de> References: <201104031726.37420.arnd@arndb.de> <20110403160324.GA8050@n2100.arm.linux.org.uk> <201104040259.26601.arnd@arndb.de> Message-ID: <1301915022.15819.28.camel@e102109-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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