Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752496Ab2FMIvD (ORCPT ); Wed, 13 Jun 2012 04:51:03 -0400 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:64133 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751207Ab2FMIvA convert rfc822-to-8bit (ORCPT ); Wed, 13 Jun 2012 04:51:00 -0400 MIME-Version: 1.0 X-Originating-IP: [87.66.97.133] In-Reply-To: <1339502524-10265-2-git-send-email-vincent.guittot@linaro.org> References: <1339502524-10265-1-git-send-email-vincent.guittot@linaro.org> <1339502524-10265-2-git-send-email-vincent.guittot@linaro.org> Date: Wed, 13 Jun 2012 10:50:59 +0200 Message-ID: Subject: Re: [RFC 1/4] ARM: topology: Add arch_scale_freq_power function From: Jean Pihet To: Vincent Guittot Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linaro-dev@lists.linaro.org, devicetree-discuss@lists.ozlabs.org, linux@arm.linux.org.uk, peterz@infradead.org, grant.likely@secretlab.ca, rob.herring@calxeda.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2248 Lines: 60 Hi Vincent, On Tue, Jun 12, 2012 at 2:02 PM, Vincent Guittot wrote: > Add infrastructure to be able to modify the cpu_power of each core > > Signed-off-by: Vincent Guittot > --- > ?arch/arm/include/asm/topology.h | ? ?2 ++ > ?arch/arm/kernel/topology.c ? ? ?| ? 36 +++++++++++++++++++++++++++++++++++- > ?2 files changed, 37 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/topology.h b/arch/arm/include/asm/topology.h > index 58b8b84..78e4c85 100644 > --- a/arch/arm/include/asm/topology.h > +++ b/arch/arm/include/asm/topology.h > @@ -27,11 +27,13 @@ void init_cpu_topology(void); > ?void store_cpu_topology(unsigned int cpuid); > ?const struct cpumask *cpu_coregroup_mask(int cpu); > > +void set_power_scale(unsigned int cpu, unsigned long power); > ?#else > > ?static inline void init_cpu_topology(void) { } > ?static inline void store_cpu_topology(unsigned int cpuid) { } > > +static inline void set_power_scale(unsigned int cpu, unsigned long power) { } > ?#endif > > ?#include > diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c > index 8200dea..00301a7 100644 > --- a/arch/arm/kernel/topology.c > +++ b/arch/arm/kernel/topology.c > @@ -22,6 +22,35 @@ > ?#include > ?#include > > +/* > + * cpu power scale management > + */ > + > +/* > + * cpu power table > + * This per cpu data structure describes the relative capacity of each core. > + * On a heteregenous system, cores don't have the same computation capacity > + * and we reflect that difference in the cpu_power field so the scheduler can > + * take this difference into account for load balance. A per cpu structure is > + * preferred because each cpu is mainly using its own cpu_power even it's not > + * always true because of nohz_idle_balance The end of the comment is unclear IMO; Can you give more details on the relation between cpu_power and nohz_idle_balance? Regards, Jean -- 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/