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.
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/
