Messages in this thread | | | Date | Mon, 26 May 2014 14:49:03 +0530 | From | Preeti U Murthy <> | Subject | Re: [PATCH v2 05/11] ARM: topology: use new cpu_power interface |
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On 05/26/2014 01:55 PM, Vincent Guittot wrote: > On 25 May 2014 15:22, Preeti U Murthy <preeti@linux.vnet.ibm.com> wrote: >> Hi Vincent, >> >> Why do we have two interfaces arch_scale_freq_power() and >> arch_scale_cpu_power()? Does it make sense to consolidate them now ? > Hi Preeti, > > They don't have the same purpose. arch_scale_cpu_power set the max > capacity of your CPU whereas arch_scale_freq_power can be used to give > the current capacity. ARM platform were using arch_scale_freq_power > because it was the only one available for non SMT system but this > induces some misunderstanding and some limitation in the > characterization of a CPUs. This consolidation is a necessary step so > we can now have the max capacity of a CPU and let > arch_scale_freq_power for other purpose (or even remove it if > useless).
Ah ok! Thanks :) This was insightful :)
Regards Preeti U Murthy > > Regards, > Vincent > >> >> Regards >> Preeti U Murthy >> >> >> On 05/23/2014 09:22 PM, Vincent Guittot wrote: >>> Use the new arch_scale_cpu_power in order to reflect the original capacity of >>> a CPU instead of arch_scale_freq_power which is more linked to a scaling of >>> the capacity linked to the frequency. >>> >>> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> >>> --- >>> arch/arm/kernel/topology.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c >>> index 71e1fec..6cc25a8 100644 >>> --- a/arch/arm/kernel/topology.c >>> +++ b/arch/arm/kernel/topology.c >>> @@ -42,7 +42,7 @@ >>> */ >>> static DEFINE_PER_CPU(unsigned long, cpu_scale); >>> >>> -unsigned long arch_scale_freq_power(struct sched_domain *sd, int cpu) >>> +unsigned long arch_scale_cpu_power(struct sched_domain *sd, int cpu) >>> { >>> return per_cpu(cpu_scale, cpu); >>> } >>> @@ -166,7 +166,7 @@ static void update_cpu_power(unsigned int cpu) >>> set_power_scale(cpu, cpu_capacity(cpu) / middle_capacity); >>> >>> printk(KERN_INFO "CPU%u: update cpu_power %lu\n", >>> - cpu, arch_scale_freq_power(NULL, cpu)); >>> + cpu, arch_scale_cpu_power(NULL, cpu)); >>> } >>> >>> #else >>> >> >
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