From mboxrd@z Thu Jan 1 00:00:00 1970 From: Morten Rasmussen Subject: [RFC PATCH 04/10] arm: Frequency invariant scheduler load-tracking support Date: Tue, 2 Dec 2014 14:06:26 +0000 Message-ID: <1417529192-11579-5-git-send-email-morten.rasmussen@arm.com> References: <1417529192-11579-1-git-send-email-morten.rasmussen@arm.com> Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Return-path: Received: from service87.mimecast.com ([91.220.42.44]:39671 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753312AbaLBOG6 (ORCPT ); Tue, 2 Dec 2014 09:06:58 -0500 In-Reply-To: <1417529192-11579-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: peterz@infradead.org, mingo@redhat.com Cc: dietmar.eggemann@arm.com, vincent.guittot@linaro.org, pjt@google.com, bsegall@google.com, mturquette@linaro.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Morten Rasmussen , Russell King , Morten Rasmussen From: Morten Rasmussen Implements arch-specific function to provide the scheduler with a frequency scaling correction factor for more accurate load-tracking. The factor is: =09current_freq(cpu) * SCHED_CAPACITY_SCALE / max_freq(cpu) This implementation only provides frequency invariance. No micro-architecture invariance yet. Cc: Russell King Signed-off-by: Morten Rasmussen --- arch/arm/kernel/topology.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index 89cfdd6..73ef337 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -169,6 +169,39 @@ static void update_cpu_capacity(unsigned int cpu) =09=09cpu, arch_scale_cpu_capacity(NULL, cpu)); } =20 +/* + * Scheduler load-tracking scale-invariance + * + * Provides the scheduler with a scale-invariance correction factor that + * compensates for frequency scaling. + */ + +static DEFINE_PER_CPU(atomic_long_t, cpu_curr_freq); +static DEFINE_PER_CPU(atomic_long_t, cpu_max_freq); + +/* cpufreq callback function setting current cpu frequency */ +void arch_scale_set_curr_freq(int cpu, unsigned long freq) +{ +=09atomic_long_set(&per_cpu(cpu_curr_freq, cpu), freq); +} + +/* cpufreq callback function setting max cpu frequency */ +void arch_scale_set_max_freq(int cpu, unsigned long freq) +{ +=09atomic_long_set(&per_cpu(cpu_max_freq, cpu), freq); +} + +unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu) +{ +=09unsigned long curr =3D atomic_long_read(&per_cpu(cpu_curr_freq, cpu)); +=09unsigned long max =3D atomic_long_read(&per_cpu(cpu_max_freq, cpu)); + +=09if (!max) +=09=09return SCHED_CAPACITY_SCALE; + +=09return (curr * SCHED_CAPACITY_SCALE) / max; +} + #else static inline void parse_dt_topology(void) {} static inline void update_cpu_capacity(unsigned int cpuid) {} --=20 1.9.1