[PATCH v2] ARM: sched_clock: allow sched_clock to be selected at runtime

Marc Zyngier marc.zyngier at arm.com
Fri Aug 12 08:24:19 EDT 2011


On 12/08/11 13:21, Jamie Iles wrote:
> On Thu, Aug 11, 2011 at 05:02:11PM +0100, 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).
>>
>> Tested on 11MPCore, OMAP4 and Tegra.
>>
>> Cc: Imre Kaloz <kaloz at openwrt.org>
>> Cc: Krzysztof Halasa <khc at pm.waw.pl>
>> Cc: Tony Lindgren <tony at atomide.com>
>> Cc: Eric Miao <eric.y.miao at gmail.com>
>> Cc: Colin Cross <ccross at android.com>
>> Cc: Erik Gilling <konkers at android.com>
>> Cc: Olof Johansson <olof at lixom.net>
>> Cc: Linus Walleij <linus.walleij at stericsson.com>
>> Cc: Sascha Hauer <kernel at pengutronix.de>
>> Cc: Alessandro Rubini <rubini at unipv.it>
>> Cc: STEricsson <STEricsson_nomadik_linux at list.st.com>
>> Cc: Lennert Buytenhek <kernel at wantstofly.org>
>> Cc: Nicolas Pitre <nico at fluxnic.net>
>> Cc: Ben Dooks <ben-linux at fluff.org>
>> Cc: Kukjin Kim <kgene.kim at samsung.com>
>> Cc: Jamie Iles <jamie at jamieiles.com>
> 
> Tested-by: Jamie Iles <jamie at jamieiles.com>

Thanks Jamie.

	M.
-- 
Jazz is not dead. It just smells funny...




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