On 9 July 2012 16:37, Shilimkar, Santosh <santosh.shilim...@ti.com> wrote: > On Mon, Jul 9, 2012 at 8:06 PM, Vincent Guittot > <vincent.guit...@linaro.org> wrote: >> On 9 July 2012 15:00, Shilimkar, Santosh <santosh.shilim...@ti.com> wrote: >>> 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. >> >> Ok, IIUC, you need a temporary methods, which doesn't need to be >> merged in mainline, to set the cpu_scale field ? >> > Yep.
You could use set_power_scale in your platform code to set the cpu_power of your CPUs until DT is ready for your platform. Regards, Vincent > > Regards > Santosh _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
