From patchwork Tue Jul 19 17:01:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 12922829 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C0653C433EF for ; Tue, 19 Jul 2022 17:33:50 +0000 (UTC) Received: from localhost ([::1]:46432 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oDr6T-0006S8-Oc for qemu-devel@archiver.kernel.org; Tue, 19 Jul 2022 13:33:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42648) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oDqcQ-0006TM-GW for qemu-devel@nongnu.org; Tue, 19 Jul 2022 13:02:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:50568) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oDqcM-0002tl-Ui for qemu-devel@nongnu.org; Tue, 19 Jul 2022 13:02:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658250162; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=J0MUwO2muIjug/dDXK3qB6R7ygQcJfeDIdmZjgQ7/T4=; b=Tm5w6OJ51DjWgYg++uO32dXMRnRLlpYQ6Q4vO90R2UGq9JtKm1Pu1s2cXWuI7SPAMf3B+4 qLHtGQIk0GSgQTPQJh+h1tjS9/gRoWPqBEg0/WU4xkxi9wDa5sqU7Mm09XQl/vapX3WZ8z BJwaSIp4TA9ZIGi9zE6HiDyeg8vGVv4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-592-i64sdA1UOgOfqDwFevI24w-1; Tue, 19 Jul 2022 13:02:35 -0400 X-MC-Unique: i64sdA1UOgOfqDwFevI24w-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 891EE8115B1; Tue, 19 Jul 2022 17:02:34 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.33.36.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7613C40CFD0B; Tue, 19 Jul 2022 17:02:33 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, leobras@redhat.com, quintela@redhat.com, berrange@redhat.com, peterx@redhat.com, iii@linux.ibm.com, huangy81@chinatelecom.cn Subject: [PULL 06/29] softmmu/dirtylimit: Implement virtual CPU throttle Date: Tue, 19 Jul 2022 18:01:58 +0100 Message-Id: <20220719170221.576190-7-dgilbert@redhat.com> In-Reply-To: <20220719170221.576190-1-dgilbert@redhat.com> References: <20220719170221.576190-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Hyman Huang(黄勇) Setup a negative feedback system when vCPU thread handling KVM_EXIT_DIRTY_RING_FULL exit by introducing throttle_us_per_full field in struct CPUState. Sleep throttle_us_per_full microseconds to throttle vCPU if dirtylimit is in service. Signed-off-by: Hyman Huang(黄勇) Reviewed-by: Peter Xu Message-Id: <977e808e03a1cef5151cae75984658b6821be618.1656177590.git.huangy81@chinatelecom.cn> Signed-off-by: Dr. David Alan Gilbert --- accel/kvm/kvm-all.c | 20 ++- include/hw/core/cpu.h | 6 + include/sysemu/dirtylimit.h | 15 ++ softmmu/dirtylimit.c | 291 ++++++++++++++++++++++++++++++++++++ softmmu/trace-events | 7 + 5 files changed, 338 insertions(+), 1 deletion(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 184aecab5c..3187656570 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -45,6 +45,7 @@ #include "qemu/guest-random.h" #include "sysemu/hw_accel.h" #include "kvm-cpus.h" +#include "sysemu/dirtylimit.h" #include "hw/boards.h" #include "monitor/stats.h" @@ -477,6 +478,7 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp) cpu->kvm_state = s; cpu->vcpu_dirty = true; cpu->dirty_pages = 0; + cpu->throttle_us_per_full = 0; mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0); if (mmap_size < 0) { @@ -1470,6 +1472,11 @@ static void *kvm_dirty_ring_reaper_thread(void *data) */ sleep(1); + /* keep sleeping so that dirtylimit not be interfered by reaper */ + if (dirtylimit_in_service()) { + continue; + } + trace_kvm_dirty_ring_reaper("wakeup"); r->reaper_state = KVM_DIRTY_RING_REAPER_REAPING; @@ -2975,8 +2982,19 @@ int kvm_cpu_exec(CPUState *cpu) */ trace_kvm_dirty_ring_full(cpu->cpu_index); qemu_mutex_lock_iothread(); - kvm_dirty_ring_reap(kvm_state, NULL); + /* + * We throttle vCPU by making it sleep once it exit from kernel + * due to dirty ring full. In the dirtylimit scenario, reaping + * all vCPUs after a single vCPU dirty ring get full result in + * the miss of sleep, so just reap the ring-fulled vCPU. + */ + if (dirtylimit_in_service()) { + kvm_dirty_ring_reap(kvm_state, cpu); + } else { + kvm_dirty_ring_reap(kvm_state, NULL); + } qemu_mutex_unlock_iothread(); + dirtylimit_vcpu_execute(cpu); ret = 0; break; case KVM_EXIT_SYSTEM_EVENT: diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index 996f94059f..500503da13 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -418,6 +418,12 @@ struct CPUState { */ bool throttle_thread_scheduled; + /* + * Sleep throttle_us_per_full microseconds once dirty ring is full + * if dirty page rate limit is enabled. + */ + int64_t throttle_us_per_full; + bool ignore_memory_transaction_failures; /* Used for user-only emulation of prctl(PR_SET_UNALIGN). */ diff --git a/include/sysemu/dirtylimit.h b/include/sysemu/dirtylimit.h index da459f03d6..8d2c1f3a6b 100644 --- a/include/sysemu/dirtylimit.h +++ b/include/sysemu/dirtylimit.h @@ -19,4 +19,19 @@ void vcpu_dirty_rate_stat_start(void); void vcpu_dirty_rate_stat_stop(void); void vcpu_dirty_rate_stat_initialize(void); void vcpu_dirty_rate_stat_finalize(void); + +void dirtylimit_state_lock(void); +void dirtylimit_state_unlock(void); +void dirtylimit_state_initialize(void); +void dirtylimit_state_finalize(void); +bool dirtylimit_in_service(void); +bool dirtylimit_vcpu_index_valid(int cpu_index); +void dirtylimit_process(void); +void dirtylimit_change(bool start); +void dirtylimit_set_vcpu(int cpu_index, + uint64_t quota, + bool enable); +void dirtylimit_set_all(uint64_t quota, + bool enable); +void dirtylimit_vcpu_execute(CPUState *cpu); #endif diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c index ebdc064c9d..e5a4f970bd 100644 --- a/softmmu/dirtylimit.c +++ b/softmmu/dirtylimit.c @@ -18,6 +18,26 @@ #include "sysemu/dirtylimit.h" #include "exec/memory.h" #include "hw/boards.h" +#include "sysemu/kvm.h" +#include "trace.h" + +/* + * Dirtylimit stop working if dirty page rate error + * value less than DIRTYLIMIT_TOLERANCE_RANGE + */ +#define DIRTYLIMIT_TOLERANCE_RANGE 25 /* MB/s */ +/* + * Plus or minus vcpu sleep time linearly if dirty + * page rate error value percentage over + * DIRTYLIMIT_LINEAR_ADJUSTMENT_PCT. + * Otherwise, plus or minus a fixed vcpu sleep time. + */ +#define DIRTYLIMIT_LINEAR_ADJUSTMENT_PCT 50 +/* + * Max vcpu sleep time percentage during a cycle + * composed of dirty ring full and sleep time. + */ +#define DIRTYLIMIT_THROTTLE_PCT_MAX 99 struct { VcpuStat stat; @@ -25,6 +45,30 @@ struct { QemuThread thread; } *vcpu_dirty_rate_stat; +typedef struct VcpuDirtyLimitState { + int cpu_index; + bool enabled; + /* + * Quota dirty page rate, unit is MB/s + * zero if not enabled. + */ + uint64_t quota; +} VcpuDirtyLimitState; + +struct { + VcpuDirtyLimitState *states; + /* Max cpus number configured by user */ + int max_cpus; + /* Number of vcpu under dirtylimit */ + int limited_nvcpu; +} *dirtylimit_state; + +/* protect dirtylimit_state */ +static QemuMutex dirtylimit_mutex; + +/* dirtylimit thread quit if dirtylimit_quit is true */ +static bool dirtylimit_quit; + static void vcpu_dirty_rate_stat_collect(void) { VcpuStat stat; @@ -54,6 +98,9 @@ static void *vcpu_dirty_rate_stat_thread(void *opaque) while (qatomic_read(&vcpu_dirty_rate_stat->running)) { vcpu_dirty_rate_stat_collect(); + if (dirtylimit_in_service()) { + dirtylimit_process(); + } } /* stop log sync */ @@ -86,9 +133,11 @@ void vcpu_dirty_rate_stat_start(void) void vcpu_dirty_rate_stat_stop(void) { qatomic_set(&vcpu_dirty_rate_stat->running, 0); + dirtylimit_state_unlock(); qemu_mutex_unlock_iothread(); qemu_thread_join(&vcpu_dirty_rate_stat->thread); qemu_mutex_lock_iothread(); + dirtylimit_state_lock(); } void vcpu_dirty_rate_stat_initialize(void) @@ -114,3 +163,245 @@ void vcpu_dirty_rate_stat_finalize(void) free(vcpu_dirty_rate_stat); vcpu_dirty_rate_stat = NULL; } + +void dirtylimit_state_lock(void) +{ + qemu_mutex_lock(&dirtylimit_mutex); +} + +void dirtylimit_state_unlock(void) +{ + qemu_mutex_unlock(&dirtylimit_mutex); +} + +static void +__attribute__((__constructor__)) dirtylimit_mutex_init(void) +{ + qemu_mutex_init(&dirtylimit_mutex); +} + +static inline VcpuDirtyLimitState *dirtylimit_vcpu_get_state(int cpu_index) +{ + return &dirtylimit_state->states[cpu_index]; +} + +void dirtylimit_state_initialize(void) +{ + MachineState *ms = MACHINE(qdev_get_machine()); + int max_cpus = ms->smp.max_cpus; + int i; + + dirtylimit_state = g_malloc0(sizeof(*dirtylimit_state)); + + dirtylimit_state->states = + g_malloc0(sizeof(VcpuDirtyLimitState) * max_cpus); + + for (i = 0; i < max_cpus; i++) { + dirtylimit_state->states[i].cpu_index = i; + } + + dirtylimit_state->max_cpus = max_cpus; + trace_dirtylimit_state_initialize(max_cpus); +} + +void dirtylimit_state_finalize(void) +{ + free(dirtylimit_state->states); + dirtylimit_state->states = NULL; + + free(dirtylimit_state); + dirtylimit_state = NULL; + + trace_dirtylimit_state_finalize(); +} + +bool dirtylimit_in_service(void) +{ + return !!dirtylimit_state; +} + +bool dirtylimit_vcpu_index_valid(int cpu_index) +{ + MachineState *ms = MACHINE(qdev_get_machine()); + + return !(cpu_index < 0 || + cpu_index >= ms->smp.max_cpus); +} + +static inline int64_t dirtylimit_dirty_ring_full_time(uint64_t dirtyrate) +{ + static uint64_t max_dirtyrate; + uint32_t dirty_ring_size = kvm_dirty_ring_size(); + uint64_t dirty_ring_size_meory_MB = + dirty_ring_size * TARGET_PAGE_SIZE >> 20; + + if (max_dirtyrate < dirtyrate) { + max_dirtyrate = dirtyrate; + } + + return dirty_ring_size_meory_MB * 1000000 / max_dirtyrate; +} + +static inline bool dirtylimit_done(uint64_t quota, + uint64_t current) +{ + uint64_t min, max; + + min = MIN(quota, current); + max = MAX(quota, current); + + return ((max - min) <= DIRTYLIMIT_TOLERANCE_RANGE) ? true : false; +} + +static inline bool +dirtylimit_need_linear_adjustment(uint64_t quota, + uint64_t current) +{ + uint64_t min, max; + + min = MIN(quota, current); + max = MAX(quota, current); + + return ((max - min) * 100 / max) > DIRTYLIMIT_LINEAR_ADJUSTMENT_PCT; +} + +static void dirtylimit_set_throttle(CPUState *cpu, + uint64_t quota, + uint64_t current) +{ + int64_t ring_full_time_us = 0; + uint64_t sleep_pct = 0; + uint64_t throttle_us = 0; + + if (current == 0) { + cpu->throttle_us_per_full = 0; + return; + } + + ring_full_time_us = dirtylimit_dirty_ring_full_time(current); + + if (dirtylimit_need_linear_adjustment(quota, current)) { + if (quota < current) { + sleep_pct = (current - quota) * 100 / current; + throttle_us = + ring_full_time_us * sleep_pct / (double)(100 - sleep_pct); + cpu->throttle_us_per_full += throttle_us; + } else { + sleep_pct = (quota - current) * 100 / quota; + throttle_us = + ring_full_time_us * sleep_pct / (double)(100 - sleep_pct); + cpu->throttle_us_per_full -= throttle_us; + } + + trace_dirtylimit_throttle_pct(cpu->cpu_index, + sleep_pct, + throttle_us); + } else { + if (quota < current) { + cpu->throttle_us_per_full += ring_full_time_us / 10; + } else { + cpu->throttle_us_per_full -= ring_full_time_us / 10; + } + } + + /* + * TODO: in the big kvm_dirty_ring_size case (eg: 65536, or other scenario), + * current dirty page rate may never reach the quota, we should stop + * increasing sleep time? + */ + cpu->throttle_us_per_full = MIN(cpu->throttle_us_per_full, + ring_full_time_us * DIRTYLIMIT_THROTTLE_PCT_MAX); + + cpu->throttle_us_per_full = MAX(cpu->throttle_us_per_full, 0); +} + +static void dirtylimit_adjust_throttle(CPUState *cpu) +{ + uint64_t quota = 0; + uint64_t current = 0; + int cpu_index = cpu->cpu_index; + + quota = dirtylimit_vcpu_get_state(cpu_index)->quota; + current = vcpu_dirty_rate_get(cpu_index); + + if (!dirtylimit_done(quota, current)) { + dirtylimit_set_throttle(cpu, quota, current); + } + + return; +} + +void dirtylimit_process(void) +{ + CPUState *cpu; + + if (!qatomic_read(&dirtylimit_quit)) { + dirtylimit_state_lock(); + + if (!dirtylimit_in_service()) { + dirtylimit_state_unlock(); + return; + } + + CPU_FOREACH(cpu) { + if (!dirtylimit_vcpu_get_state(cpu->cpu_index)->enabled) { + continue; + } + dirtylimit_adjust_throttle(cpu); + } + dirtylimit_state_unlock(); + } +} + +void dirtylimit_change(bool start) +{ + if (start) { + qatomic_set(&dirtylimit_quit, 0); + } else { + qatomic_set(&dirtylimit_quit, 1); + } +} + +void dirtylimit_set_vcpu(int cpu_index, + uint64_t quota, + bool enable) +{ + trace_dirtylimit_set_vcpu(cpu_index, quota); + + if (enable) { + dirtylimit_state->states[cpu_index].quota = quota; + if (!dirtylimit_vcpu_get_state(cpu_index)->enabled) { + dirtylimit_state->limited_nvcpu++; + } + } else { + dirtylimit_state->states[cpu_index].quota = 0; + if (dirtylimit_state->states[cpu_index].enabled) { + dirtylimit_state->limited_nvcpu--; + } + } + + dirtylimit_state->states[cpu_index].enabled = enable; +} + +void dirtylimit_set_all(uint64_t quota, + bool enable) +{ + MachineState *ms = MACHINE(qdev_get_machine()); + int max_cpus = ms->smp.max_cpus; + int i; + + for (i = 0; i < max_cpus; i++) { + dirtylimit_set_vcpu(i, quota, enable); + } +} + +void dirtylimit_vcpu_execute(CPUState *cpu) +{ + if (dirtylimit_in_service() && + dirtylimit_vcpu_get_state(cpu->cpu_index)->enabled && + cpu->throttle_us_per_full) { + trace_dirtylimit_vcpu_execute(cpu->cpu_index, + cpu->throttle_us_per_full); + usleep(cpu->throttle_us_per_full); + } +} diff --git a/softmmu/trace-events b/softmmu/trace-events index 9c88887b3c..22606dc27b 100644 --- a/softmmu/trace-events +++ b/softmmu/trace-events @@ -31,3 +31,10 @@ runstate_set(int current_state, const char *current_state_str, int new_state, co system_wakeup_request(int reason) "reason=%d" qemu_system_shutdown_request(int reason) "reason=%d" qemu_system_powerdown_request(void) "" + +#dirtylimit.c +dirtylimit_state_initialize(int max_cpus) "dirtylimit state initialize: max cpus %d" +dirtylimit_state_finalize(void) +dirtylimit_throttle_pct(int cpu_index, uint64_t pct, int64_t time_us) "CPU[%d] throttle percent: %" PRIu64 ", throttle adjust time %"PRIi64 " us" +dirtylimit_set_vcpu(int cpu_index, uint64_t quota) "CPU[%d] set dirty page rate limit %"PRIu64 +dirtylimit_vcpu_execute(int cpu_index, int64_t sleep_time_us) "CPU[%d] sleep %"PRIi64 " us"