Messages in this thread | | | From | Vincent Guittot <> | Date | Mon, 26 May 2014 10:25:41 +0200 | Subject | Re: [PATCH v2 05/11] ARM: topology: use new cpu_power interface |
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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).
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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