From patchwork Fri May 29 10:10:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudio Fontana X-Patchwork-Id: 281688 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFE2CC433E0 for ; Fri, 29 May 2020 10:14:13 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A44F62074D for ; Fri, 29 May 2020 10:14:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A44F62074D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39002 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jec1k-0004Yc-S1 for qemu-devel@archiver.kernel.org; Fri, 29 May 2020 06:14:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54404) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jebyi-0008Tb-Lg for qemu-devel@nongnu.org; Fri, 29 May 2020 06:11:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:55348) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jebye-0002cU-Hd for qemu-devel@nongnu.org; Fri, 29 May 2020 06:11:04 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 68AE9ADC8; Fri, 29 May 2020 10:10:57 +0000 (UTC) From: Claudio Fontana To: Paolo Bonzini , Thomas Huth , =?utf-8?q?Alex_Benn=C3=A9e?= , Peter Maydell , =?utf-8?q?Philippe_Mathieu-?= =?utf-8?b?RGF1ZMOp?= , Roman Bolshakov Subject: [RFC v4 2/4] cpu-throttle: new module, extracted from cpus.c Date: Fri, 29 May 2020 12:10:51 +0200 Message-Id: <20200529101053.4045-3-cfontana@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200529101053.4045-1-cfontana@suse.de> References: <20200529101053.4045-1-cfontana@suse.de> Received-SPF: pass client-ip=195.135.220.15; envelope-from=cfontana@suse.de; helo=mx2.suse.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/29 02:21:57 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x (no timestamps) [generic] X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Eduardo Habkost , Marcelo Tosatti , qemu-devel@nongnu.org, Colin Xu , Wenchao Wang , haxm-team@intel.com, Sunil Muthuswamy , Richard Henderson , Claudio Fontana Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" move the vcpu throttling functionality into its own module. This functionality is not specific to any accelerator, and it is used currently by migration to slow down guests to try to have migrations converge, and by the cocoa MacOS UI to throttle speed. cpu-throttle contains the controls to adjust and inspect throttle settings, start (set) and stop vcpu throttling, and the throttling function itself that is run periodically on vcpus to make them take a nap. Execution of the throttling function on all vcpus is triggered by a timer, registered at module initialization. No functionality change. Signed-off-by: Claudio Fontana --- MAINTAINERS | 1 + include/hw/core/cpu.h | 37 ------------- include/qemu/main-loop.h | 5 ++ include/sysemu/cpu-throttle.h | 68 +++++++++++++++++++++++ migration/migration.c | 1 + migration/ram.c | 1 + softmmu/Makefile.objs | 1 + softmmu/cpu-throttle.c | 122 ++++++++++++++++++++++++++++++++++++++++++ softmmu/cpus.c | 95 +++----------------------------- 9 files changed, 207 insertions(+), 124 deletions(-) create mode 100644 include/sysemu/cpu-throttle.h create mode 100644 softmmu/cpu-throttle.c diff --git a/MAINTAINERS b/MAINTAINERS index dc439bb6f4..e411e81a52 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2156,6 +2156,7 @@ F: util/qemu-timer.c F: softmmu/vl.c F: softmmu/main.c F: softmmu/cpus.c +F: softmmu/cpu-throttle.c F: qapi/run-state.json Human Monitor (HMP) diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index 07f7698155..e6b75d456c 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -817,43 +817,6 @@ bool cpu_exists(int64_t id); */ CPUState *cpu_by_arch_id(int64_t id); -/** - * cpu_throttle_set: - * @new_throttle_pct: Percent of sleep time. Valid range is 1 to 99. - * - * Throttles all vcpus by forcing them to sleep for the given percentage of - * time. A throttle_percentage of 25 corresponds to a 75% duty cycle roughly. - * (example: 10ms sleep for every 30ms awake). - * - * cpu_throttle_set can be called as needed to adjust new_throttle_pct. - * Once the throttling starts, it will remain in effect until cpu_throttle_stop - * is called. - */ -void cpu_throttle_set(int new_throttle_pct); - -/** - * cpu_throttle_stop: - * - * Stops the vcpu throttling started by cpu_throttle_set. - */ -void cpu_throttle_stop(void); - -/** - * cpu_throttle_active: - * - * Returns: %true if the vcpus are currently being throttled, %false otherwise. - */ -bool cpu_throttle_active(void); - -/** - * cpu_throttle_get_percentage: - * - * Returns the vcpu throttle percentage. See cpu_throttle_set for details. - * - * Returns: The throttle percentage in range 1 to 99. - */ -int cpu_throttle_get_percentage(void); - #ifndef CONFIG_USER_ONLY typedef void (*CPUInterruptHandler)(CPUState *, int); diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h index a6d20b0719..8e98613656 100644 --- a/include/qemu/main-loop.h +++ b/include/qemu/main-loop.h @@ -303,6 +303,11 @@ void qemu_mutex_unlock_iothread(void); */ void qemu_cond_wait_iothread(QemuCond *cond); +/* + * qemu_cond_timedwait_iothread: like the previous, but with timeout + */ +void qemu_cond_timedwait_iothread(QemuCond *cond, int ms); + /* internal interfaces */ void qemu_fd_register(int fd); diff --git a/include/sysemu/cpu-throttle.h b/include/sysemu/cpu-throttle.h new file mode 100644 index 0000000000..d65bdef6d0 --- /dev/null +++ b/include/sysemu/cpu-throttle.h @@ -0,0 +1,68 @@ +/* + * Copyright (c) 2012 SUSE LINUX Products GmbH + * + * 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; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see + * + */ + +#ifndef SYSEMU_CPU_THROTTLE_H +#define SYSEMU_CPU_THROTTLE_H + +#include "qemu/timer.h" + +/** + * cpu_throttle_init: + * + * Initialize the CPU throttling API. + */ +void cpu_throttle_init(void); + +/** + * cpu_throttle_set: + * @new_throttle_pct: Percent of sleep time. Valid range is 1 to 99. + * + * Throttles all vcpus by forcing them to sleep for the given percentage of + * time. A throttle_percentage of 25 corresponds to a 75% duty cycle roughly. + * (example: 10ms sleep for every 30ms awake). + * + * cpu_throttle_set can be called as needed to adjust new_throttle_pct. + * Once the throttling starts, it will remain in effect until cpu_throttle_stop + * is called. + */ +void cpu_throttle_set(int new_throttle_pct); + +/** + * cpu_throttle_stop: + * + * Stops the vcpu throttling started by cpu_throttle_set. + */ +void cpu_throttle_stop(void); + +/** + * cpu_throttle_active: + * + * Returns: %true if the vcpus are currently being throttled, %false otherwise. + */ +bool cpu_throttle_active(void); + +/** + * cpu_throttle_get_percentage: + * + * Returns the vcpu throttle percentage. See cpu_throttle_set for details. + * + * Returns: The throttle percentage in range 1 to 99. + */ +int cpu_throttle_get_percentage(void); + +#endif /* SYSEMU_CPU_THROTTLE_H */ diff --git a/migration/migration.c b/migration/migration.c index 0bb042a0f7..dd18323f32 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -23,6 +23,7 @@ #include "socket.h" #include "sysemu/runstate.h" #include "sysemu/sysemu.h" +#include "sysemu/cpu-throttle.h" #include "rdma.h" #include "ram.h" #include "migration/global_state.h" diff --git a/migration/ram.c b/migration/ram.c index 859f835f1a..527f0c7316 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -52,6 +52,7 @@ #include "migration/colo.h" #include "block.h" #include "sysemu/sysemu.h" +#include "sysemu/cpu-throttle.h" #include "savevm.h" #include "qemu/iov.h" #include "multifd.h" diff --git a/softmmu/Makefile.objs b/softmmu/Makefile.objs index a4bd9f2f52..a414a74c50 100644 --- a/softmmu/Makefile.objs +++ b/softmmu/Makefile.objs @@ -2,6 +2,7 @@ softmmu-main-y = softmmu/main.o obj-y += arch_init.o obj-y += cpus.o +obj-y += cpu-throttle.o obj-y += balloon.o obj-y += ioport.o obj-y += memory.o diff --git a/softmmu/cpu-throttle.c b/softmmu/cpu-throttle.c new file mode 100644 index 0000000000..4e6b2818ca --- /dev/null +++ b/softmmu/cpu-throttle.c @@ -0,0 +1,122 @@ +/* + * QEMU System Emulator + * + * Copyright (c) 2003-2008 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu-common.h" +#include "qemu/thread.h" +#include "hw/core/cpu.h" +#include "qemu/main-loop.h" +#include "sysemu/cpus.h" +#include "sysemu/cpu-throttle.h" + +/* vcpu throttling controls */ +static QEMUTimer *throttle_timer; +static unsigned int throttle_percentage; + +#define CPU_THROTTLE_PCT_MIN 1 +#define CPU_THROTTLE_PCT_MAX 99 +#define CPU_THROTTLE_TIMESLICE_NS 10000000 + +static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque) +{ + double pct; + double throttle_ratio; + int64_t sleeptime_ns, endtime_ns; + + if (!cpu_throttle_get_percentage()) { + return; + } + + pct = (double)cpu_throttle_get_percentage() / 100; + throttle_ratio = pct / (1 - pct); + /* Add 1ns to fix double's rounding error (like 0.9999999...) */ + sleeptime_ns = (int64_t)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS + 1); + endtime_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + sleeptime_ns; + while (sleeptime_ns > 0 && !cpu->stop) { + if (sleeptime_ns > SCALE_MS) { + qemu_cond_timedwait_iothread(cpu->halt_cond, + sleeptime_ns / SCALE_MS); + } else { + qemu_mutex_unlock_iothread(); + g_usleep(sleeptime_ns / SCALE_US); + qemu_mutex_lock_iothread(); + } + sleeptime_ns = endtime_ns - qemu_clock_get_ns(QEMU_CLOCK_REALTIME); + } + atomic_set(&cpu->throttle_thread_scheduled, 0); +} + +static void cpu_throttle_timer_tick(void *opaque) +{ + CPUState *cpu; + double pct; + + /* Stop the timer if needed */ + if (!cpu_throttle_get_percentage()) { + return; + } + CPU_FOREACH(cpu) { + if (!atomic_xchg(&cpu->throttle_thread_scheduled, 1)) { + async_run_on_cpu(cpu, cpu_throttle_thread, + RUN_ON_CPU_NULL); + } + } + + pct = (double)cpu_throttle_get_percentage() / 100; + timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) + + CPU_THROTTLE_TIMESLICE_NS / (1 - pct)); +} + +void cpu_throttle_set(int new_throttle_pct) +{ + /* Ensure throttle percentage is within valid range */ + new_throttle_pct = MIN(new_throttle_pct, CPU_THROTTLE_PCT_MAX); + new_throttle_pct = MAX(new_throttle_pct, CPU_THROTTLE_PCT_MIN); + + atomic_set(&throttle_percentage, new_throttle_pct); + + timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) + + CPU_THROTTLE_TIMESLICE_NS); +} + +void cpu_throttle_stop(void) +{ + atomic_set(&throttle_percentage, 0); +} + +bool cpu_throttle_active(void) +{ + return (cpu_throttle_get_percentage() != 0); +} + +int cpu_throttle_get_percentage(void) +{ + return atomic_read(&throttle_percentage); +} + +void cpu_throttle_init(void) +{ + throttle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT, + cpu_throttle_timer_tick, NULL); +} diff --git a/softmmu/cpus.c b/softmmu/cpus.c index 5670c96bcf..3a46a4fc2b 100644 --- a/softmmu/cpus.c +++ b/softmmu/cpus.c @@ -61,6 +61,8 @@ #include "hw/boards.h" #include "hw/hw.h" +#include "sysemu/cpu-throttle.h" + #ifdef CONFIG_LINUX #include @@ -84,14 +86,6 @@ static QemuMutex qemu_global_mutex; int64_t max_delay; int64_t max_advance; -/* vcpu throttling controls */ -static QEMUTimer *throttle_timer; -static unsigned int throttle_percentage; - -#define CPU_THROTTLE_PCT_MIN 1 -#define CPU_THROTTLE_PCT_MAX 99 -#define CPU_THROTTLE_TIMESLICE_NS 10000000 - bool cpu_is_stopped(CPUState *cpu) { return cpu->stopped || !runstate_is_running(); @@ -710,90 +704,12 @@ static const VMStateDescription vmstate_timers = { } }; -static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque) -{ - double pct; - double throttle_ratio; - int64_t sleeptime_ns, endtime_ns; - - if (!cpu_throttle_get_percentage()) { - return; - } - - pct = (double)cpu_throttle_get_percentage()/100; - throttle_ratio = pct / (1 - pct); - /* Add 1ns to fix double's rounding error (like 0.9999999...) */ - sleeptime_ns = (int64_t)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS + 1); - endtime_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + sleeptime_ns; - while (sleeptime_ns > 0 && !cpu->stop) { - if (sleeptime_ns > SCALE_MS) { - qemu_cond_timedwait(cpu->halt_cond, &qemu_global_mutex, - sleeptime_ns / SCALE_MS); - } else { - qemu_mutex_unlock_iothread(); - g_usleep(sleeptime_ns / SCALE_US); - qemu_mutex_lock_iothread(); - } - sleeptime_ns = endtime_ns - qemu_clock_get_ns(QEMU_CLOCK_REALTIME); - } - atomic_set(&cpu->throttle_thread_scheduled, 0); -} - -static void cpu_throttle_timer_tick(void *opaque) -{ - CPUState *cpu; - double pct; - - /* Stop the timer if needed */ - if (!cpu_throttle_get_percentage()) { - return; - } - CPU_FOREACH(cpu) { - if (!atomic_xchg(&cpu->throttle_thread_scheduled, 1)) { - async_run_on_cpu(cpu, cpu_throttle_thread, - RUN_ON_CPU_NULL); - } - } - - pct = (double)cpu_throttle_get_percentage()/100; - timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) + - CPU_THROTTLE_TIMESLICE_NS / (1-pct)); -} - -void cpu_throttle_set(int new_throttle_pct) -{ - /* Ensure throttle percentage is within valid range */ - new_throttle_pct = MIN(new_throttle_pct, CPU_THROTTLE_PCT_MAX); - new_throttle_pct = MAX(new_throttle_pct, CPU_THROTTLE_PCT_MIN); - - atomic_set(&throttle_percentage, new_throttle_pct); - - timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) + - CPU_THROTTLE_TIMESLICE_NS); -} - -void cpu_throttle_stop(void) -{ - atomic_set(&throttle_percentage, 0); -} - -bool cpu_throttle_active(void) -{ - return (cpu_throttle_get_percentage() != 0); -} - -int cpu_throttle_get_percentage(void) -{ - return atomic_read(&throttle_percentage); -} - void cpu_ticks_init(void) { seqlock_init(&timers_state.vm_clock_seqlock); qemu_spin_init(&timers_state.vm_clock_lock); vmstate_register(NULL, 0, &vmstate_timers, &timers_state); - throttle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT, - cpu_throttle_timer_tick, NULL); + cpu_throttle_init(); } void configure_icount(QemuOpts *opts, Error **errp) @@ -1852,6 +1768,11 @@ void qemu_cond_wait_iothread(QemuCond *cond) qemu_cond_wait(cond, &qemu_global_mutex); } +void qemu_cond_timedwait_iothread(QemuCond *cond, int ms) +{ + qemu_cond_timedwait(cond, &qemu_global_mutex, ms); +} + static bool all_vcpus_paused(void) { CPUState *cpu;