From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754658AbaIVQZf (ORCPT ); Mon, 22 Sep 2014 12:25:35 -0400 Received: from service87.mimecast.com ([91.220.42.44]:60287 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754538AbaIVQYI (ORCPT ); Mon, 22 Sep 2014 12:24:08 -0400 From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: dietmar.eggemann@arm.com, pjt@google.com, bsegall@google.com, vincent.guittot@linaro.org, nicolas.pitre@linaro.org, mturquette@linaro.org, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, Morten Rasmussen Subject: [PATCH 3/7] arm: Frequency invariant scheduler load-tracking support Date: Mon, 22 Sep 2014 17:24:03 +0100 Message-Id: <1411403047-32010-4-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1411403047-32010-1-git-send-email-morten.rasmussen@arm.com> References: <1411403047-32010-1-git-send-email-morten.rasmussen@arm.com> X-OriginalArrivalTime: 22 Sep 2014 16:24:05.0924 (UTC) FILETIME=[A11DBE40:01CFD681] X-MC-Unique: 114092217240600201 Content-Type: text/plain; charset=WINDOWS-1252 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id s8MGPdpJ029534 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. 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..3e9a979 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_load_capacity(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 (!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) {} -- 1.7.9.5