On Mon, Jul 9, 2012 at 6:02 PM, Vincent Guittot <vincent.guit...@linaro.org> wrote: > On 9 July 2012 12:55, Shilimkar, Santosh <santosh.shilim...@ti.com> wrote: >> Vincent, >> On Mon, Jul 9, 2012 at 2:57 PM, Vincent Guittot >> <vincent.guit...@linaro.org> wrote: >>> Use cpu compatibility field and clock-frequency field of DT to >>> estimate the capacity of each core of the system and to update >>> the cpu_power field accordingly. >>> This patch enables to put more running tasks on big cores than >>> on LITTLE ones. But this patch doesn't ensure that long running >>> tasks will run on big cores and short ones on LITTLE cores. >>> >>> Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org> >>> Reviewed-by: Namhyung Kim <namhy...@kernel.org> >>> --- >>> arch/arm/kernel/topology.c | 153 >>> ++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 153 insertions(+) >>> >> Sorry for not giving this comment on previous version but we should also >> have a way to provide the big.LITTLE information without Device Tree. >> May be a platform device/data. > > Hi Santosh, > > I had thought of adding such additional way to set cpu_power of > big.LITTLE but my conclusion was > -it's a new platform so it should come with DT > -DT is already required by other patches linked to big.LITTLE > (http://lists.infradead.org/pipermail/linux-arm-kernel/2012-January/080873.html) > -There is no device that can be easily used to get such information at > this early boot stage. > I see. Its new processor but it is just 1 one of the IP in an entire SOC. As mentioned below I was talking about full SOC support including all the driver subsystem with DT.
>> >> I know we are moving DT way, but remember apart from core kernel >> infrastructure, to have a complete product build with DT means all the >> drivers must be already supporting DT which is not the case with >> many huge driver sub-systems like USB, display subsystem, Audio etc. >> >> Having that support would greatly help for the SOC's which have not yet >> reached to stage where entire SOC is DT compliant and want to use >> big.LITTLE infrastructure. > > Can't you support both type of devices on your platform ? You can move > your device to DT mode when it is supported ? > That is what eventually people end up doing who don't have DT ready for entire SOC. I was trying to ask whether at least some method is proposed(need not be merged in mainline) to have the big.LITTLE information parsing without DT. Regards Santosh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
