| Message ID | 1400860385-14555-6-git-send-email-vincent.guittot@linaro.org |
|---|---|
| State | New |
| Headers | show |
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 ? 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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 >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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 >>> >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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
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(-)