From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161622AbbBDSbJ (ORCPT ); Wed, 4 Feb 2015 13:31:09 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:41559 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161590AbbBDSbD (ORCPT ); Wed, 4 Feb 2015 13:31:03 -0500 From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: vincent.guittot@linaro.org, dietmar.eggemann@arm.com, yuyang.du@intel.com, preeti@linux.vnet.ibm.com, mturquette@linaro.org, nico@linaro.org, rjw@rjwysocki.net, juri.lelli@arm.com, linux-kernel@vger.kernel.org, Morten Rasmussen , Russell King Subject: [RFCv3 PATCH 14/48] arm: Frequency invariant scheduler load-tracking support Date: Wed, 4 Feb 2015 18:30:51 +0000 Message-Id: <1423074685-6336-15-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1423074685-6336-1-git-send-email-morten.rasmussen@arm.com> References: <1423074685-6336-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: current_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 08b7847..a1274e6 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) cpu, arch_scale_cpu_capacity(NULL, cpu)); } +/* + * 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) +{ + atomic_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) +{ + atomic_long_set(&per_cpu(cpu_max_freq, cpu), freq); +} + +unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu) +{ + unsigned long curr = atomic_long_read(&per_cpu(cpu_curr_freq, cpu)); + unsigned long max = atomic_long_read(&per_cpu(cpu_max_freq, cpu)); + + if (!curr || !max) + return SCHED_CAPACITY_SCALE; + + return (curr * SCHED_CAPACITY_SCALE) / max; +} + #else static inline void parse_dt_topology(void) {} static inline void update_cpu_capacity(unsigned int cpuid) {} -- 1.9.1