From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 10 Aug 2011 09:28:02 +0100 Subject: [RFC PATCH] ARM: sched_clock: allow sched_clock to be selected at runtime In-Reply-To: References: <1312910015-20043-1-git-send-email-marc.zyngier@arm.com> <4E41A4A4.80000@gmail.com> Message-ID: <4E424112.10804@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 09/08/11 22:28, Eric Miao wrote: > On Wed, Aug 10, 2011 at 5:20 AM, Rob Herring wrote: >> On 08/09/2011 12:13 PM, Marc Zyngier wrote: >>> sched_clock() is yet another blocker on the road to the single >>> image. This patch implements an idea by Russell King: >>> >>> http://www.spinics.net/lists/linux-omap/msg49561.html >>> >>> Instead of asking the platform to implement both sched_clock() >>> itself and the rollover callback, simply register a read() >>> function, and let the ARM code care about sched_clock() itself, >>> the conversion to ns and the rollover. sched_clock() uses >>> this read() function as an indirection to the platform code. >>> >>> This allow some simplifications and possibly some footprint gain >>> when multiple platforms are compiled in. Among the drawbacks, >>> the removal of the *_fixed_sched_clock optimization which could >>> negatively impact some platforms (sa1100, tegra, versatile >>> and omap). >> >> There are similar patchsets that move sched_clock into clocksource code. >> That seems like a cleaner approach to me. >> >> http://thread.gmane.org/gmane.linux.kernel/844872 >> >> http://www.spinics.net/lists/arm-kernel/msg122716.html > > +1, yeah would be better for clocksource to handle that if possible. I'd be all for that, and I've waited a long time (April?) before posting that patch, hoping that a consensus would emerge on the clocksourse patches. So far, nothing. We need a solution to this problem. I really don't care which patch gets merged, so if someone thinks they can get the clocksource patches further, then by all mean, please do it. Cheers, M. -- Jazz is not dead. It just smells funny...