From patchwork Wed Sep 21 19:19:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: srinivas pandruvada X-Patchwork-Id: 9344133 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3FB98607D4 for ; Wed, 21 Sep 2016 19:21:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2E5092A853 for ; Wed, 21 Sep 2016 19:21:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2312A2A85A; Wed, 21 Sep 2016 19:21:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 99C932A853 for ; Wed, 21 Sep 2016 19:21:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941076AbcIUTUh (ORCPT ); Wed, 21 Sep 2016 15:20:37 -0400 Received: from mga05.intel.com ([192.55.52.43]:21846 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S940174AbcIUTT0 (ORCPT ); Wed, 21 Sep 2016 15:19:26 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga105.fm.intel.com with ESMTP; 21 Sep 2016 12:19:23 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,375,1470726000"; d="scan'208";a="764204831" Received: from spandruv-desk.jf.intel.com ([10.54.75.13]) by FMSMGA003.fm.intel.com with ESMTP; 21 Sep 2016 12:19:23 -0700 From: Srinivas Pandruvada To: rjw@rjwysocki.net, tglx@linutronix.de, mingo@redhat.com, bp@suse.de Cc: x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, peterz@infradead.org, tim.c.chen@linux.intel.com, jolsa@redhat.com, Srinivas Pandruvada Subject: [PATCH v4 05/10] x86: Enable Intel Turbo Boost Max Technology 3.0 Date: Wed, 21 Sep 2016 12:19:07 -0700 Message-Id: <1474485552-141429-6-git-send-email-srinivas.pandruvada@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1474485552-141429-1-git-send-email-srinivas.pandruvada@linux.intel.com> References: <1474485552-141429-1-git-send-email-srinivas.pandruvada@linux.intel.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Tim Chen On platforms supporting Intel Turbo Boost Max Technology 3.0, the maximum turbo frequencies of some cores in a CPU package may be higher than for the other cores in the same package. In that case, better performance (and possibly lower energy consumption as well) can be achieved by making the scheduler prefer to run tasks on the CPUs with higher max turbo frequencies. To that end, set up a core priority metric to abstract the core preferences based on the maximum turbo frequency. In that metric, the cores with higher maximum turbo frequencies are higher-priority than the other cores in the same package and that causes the scheduler to favor them when making load-balancing decisions using the asymmertic packing approach. At the same time, the priority of SMT threads with a higher CPU number is reduced so as to avoid scheduling tasks on all of the threads that belong to a favored core before all of the other cores have been given a task to run. The priority metric will be initialized by the P-state driver with the help of the sched_set_itmt_core_prio() function. The P-state driver will also determine whether or not ITMT is supported by the platform and will call sched_set_itmt_support() to indicate that. Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Srinivas Pandruvada --- arch/x86/Kconfig | 9 ++++ arch/x86/include/asm/topology.h | 22 ++++++++++ arch/x86/kernel/Makefile | 1 + arch/x86/kernel/itmt.c | 91 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 123 insertions(+) create mode 100644 arch/x86/kernel/itmt.c diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2a1f0ce..6dfb97d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -927,6 +927,15 @@ config SCHED_MC making when dealing with multi-core CPU chips at a cost of slightly increased overhead in some places. If unsure say N here. +config SCHED_ITMT + bool "Intel Turbo Boost Max Technology (ITMT) scheduler support" + depends on SCHED_MC && CPU_SUP_INTEL && X86_INTEL_PSTATE + ---help--- + ITMT enabled scheduler support improves the CPU scheduler's decision + to move tasks to cpu core that can be boosted to a higher frequency + than others. It will have better performance at a cost of slightly + increased overhead in task migrations. If unsure say N here. + source "kernel/Kconfig.preempt" config UP_LATE_INIT diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index 323f61f..637d847 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -150,4 +150,26 @@ int x86_pci_root_bus_node(int bus); void x86_pci_root_bus_resources(int bus, struct list_head *resources); extern bool x86_topology_update; + +#ifdef CONFIG_SCHED_ITMT +#include + +DECLARE_PER_CPU_READ_MOSTLY(int, sched_core_priority); + +/* Interface to set priority of a cpu */ +void sched_set_itmt_core_prio(int prio, int core_cpu); + +/* Interface to notify scheduler that system supports ITMT */ +void sched_set_itmt_support(bool itmt_supported); + +#else /* CONFIG_SCHED_ITMT */ + +static inline void sched_set_itmt_core_prio(int prio, int core_cpu) +{ +} +static inline void sched_set_itmt_support(bool itmt_supported) +{ +} +#endif /* CONFIG_SCHED_ITMT */ + #endif /* _ASM_X86_TOPOLOGY_H */ diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 0503f5b..2008335 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -124,6 +124,7 @@ obj-$(CONFIG_EFI) += sysfb_efi.o obj-$(CONFIG_PERF_EVENTS) += perf_regs.o obj-$(CONFIG_TRACING) += tracepoint.o +obj-$(CONFIG_SCHED_ITMT) += itmt.o ### # 64 bit specific files diff --git a/arch/x86/kernel/itmt.c b/arch/x86/kernel/itmt.c new file mode 100644 index 0000000..3e1636b --- /dev/null +++ b/arch/x86/kernel/itmt.c @@ -0,0 +1,91 @@ +/* + * itmt.c: Support Intel Turbo Boost Max Technology 3.0 + * + * (C) Copyright 2016 Intel Corporation + * Author: Tim Chen + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + * + * On platforms supporting Intel Turbo Boost Max Technology 3.0, (ITMT), + * the maximum turbo frequencies of some cores in a CPU package may be + * higher than for the other cores in the same package. In that case, + * better performance can be achieved by making the scheduler prefer + * to run tasks on the CPUs with higher max turbo frequencies. + * + * This file provides functions and data structures for enabling the + * scheduler to favor scheduling on cores can be boosted to a higher + * frequency under ITMT. + */ + +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_MUTEX(itmt_update_mutex); + +/* Boolean to track if system has ITMT capabilities */ +static bool __read_mostly sched_itmt_capable; + +/** + * sched_set_itmt_support - Indicate platform support ITMT + * @itmt_supported: indicate platform's CPU has ITMT capability + * + * This function is used by the OS to indicate to scheduler if the platform + * is capable of supporting the ITMT feature. + * + * The current scheme has the pstate driver detects if the system + * is ITMT capable and call this function. + * + * This must be done only after sched_set_itmt_core_prio + * has been called to set the cpus' priorities. + */ +void sched_set_itmt_support(bool itmt_supported) +{ + mutex_lock(&itmt_update_mutex); + + if (itmt_supported != sched_itmt_capable) + sched_itmt_capable = itmt_supported; + + mutex_unlock(&itmt_update_mutex); +} + +DEFINE_PER_CPU_READ_MOSTLY(int, sched_core_priority); +int arch_asym_cpu_priority(int cpu) +{ + return per_cpu(sched_core_priority, cpu); +} + +/** + * sched_set_itmt_core_prio - Set CPU priority based on ITMT + * @prio: Priority of cpu core + * @core_cpu: The cpu number associated with the core + * + * The pstate driver will find out the max boost frequency + * and call this function to set a priority proportional + * to the max boost frequency. CPU with higher boost + * frequency will receive higher priority. + */ +void sched_set_itmt_core_prio(int prio, int core_cpu) +{ + int cpu, i = 1; + + for_each_cpu(cpu, topology_sibling_cpumask(core_cpu)) { + int smt_prio; + + /* + * Ensure that the siblings are moved to the end + * of the priority chain and only used when + * all other high priority cpus are out of capacity. + */ + smt_prio = prio * smp_num_siblings / i; + i++; + per_cpu(sched_core_priority, cpu) = smt_prio; + } +}