From patchwork Thu Jan 11 08:26:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 124159 Delivered-To: patch@linaro.org Received: by 10.140.22.227 with SMTP id 90csp374174qgn; Thu, 11 Jan 2018 00:40:06 -0800 (PST) X-Google-Smtp-Source: ACJfBotPtpkFtH42pd6EkhaL0I+KtwINVNeOmB9DdghnNCjXaSr1e2fa00+8Ih3ag6RORc0uie7y X-Received: by 10.37.123.133 with SMTP id w127mr19414848ybc.69.1515660006036; Thu, 11 Jan 2018 00:40:06 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1515660006; cv=none; d=google.com; s=arc-20160816; b=nApiVNksN2oBL3TGkDgr5aYRhOGO0C5Xc5llUrizEyI1e3yd0+tTKT+c4ugpgX8LXG RBgRli/P898DFCJCunzZBZ4Iqbd1b/vty6LNM3O6PlwK9+Fd6VNBiOJivXNPUPjn50mE tyN4j7Gm1WZ3+m4Mq31B7JlC93Ohd+VcDmPJiuSYjQB4uC5VdRAUkthEeRoo/6xlArpa +B8SYQ8l9m+e6NFjeXtRFqFJtFTPFgo7rGVvwQZA27qodKR0rAh0/JxZSSgE0TCXyklD MIb0oeyYlDBmB4rDNCfi61N3Z+p5CLRUSObpMEF7go7TNU9riV/uQ0CIhudpFLcRi47Z +XPA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:cc:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject :content-transfer-encoding:mime-version:user-agent:references :in-reply-to:message-id:date:to:from:arc-authentication-results; bh=Tqjf52OC9FSA9jwTviqdoEm46WowEekT83MjICedetk=; b=OUZ0t+Ss1n5hfOXvz8qJTknq2sHDAQBYxMcqMxAKwarmGAbRFxT84MK6vHI3nZNb72 PrDDrJ2n/4ipKpvbvUgYezlitp9noys5kk8zceRhQYTzIZtzMCIJWjuWFQx6gWUJ++QS Cjx7/4w9fCVLesiaHTPfhsqbikjSdm/Oyb8AzZAaKjRXbUXWRl/jYQ/vaoeRk2f4XEN6 E09TIldGJ/3eAGV1+VL4RXVDgp+8lmO0N3fjlMOjE0EhVkZ/suJLaVuziNaX7pkUc7Lc rzus3RIHQiMFl4qm1vyUlJ96wtDkidTjBeldzLSpWb95ciylKXp6JYy+cBbDFK0Z+nVD 2ESg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) smtp.mailfrom=qemu-devel-bounces+patch=linaro.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org. [2001:4830:134:3::11]) by mx.google.com with ESMTPS id b69si1418833ywe.676.2018.01.11.00.40.05 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 11 Jan 2018 00:40:06 -0800 (PST) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) client-ip=2001:4830:134:3::11; Authentication-Results: mx.google.com; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) smtp.mailfrom=qemu-devel-bounces+patch=linaro.org@nongnu.org Received: from localhost ([::1]:53098 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZYP7-0003fA-H4 for patch@linaro.org; Thu, 11 Jan 2018 03:40:05 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46646) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZYBs-0000aW-KU for qemu-devel@nongnu.org; Thu, 11 Jan 2018 03:26:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eZYBo-0001K4-JF for qemu-devel@nongnu.org; Thu, 11 Jan 2018 03:26:24 -0500 Received: from mail.ispras.ru ([83.149.199.45]:41772) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZYBo-0001JW-72 for qemu-devel@nongnu.org; Thu, 11 Jan 2018 03:26:20 -0500 Received: from [127.0.1.1] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id 58BB954006A; Thu, 11 Jan 2018 11:26:19 +0300 (MSK) From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Thu, 11 Jan 2018 11:26:21 +0300 Message-ID: <20180111082621.27295.81834.stgit@pasha-VirtualBox> In-Reply-To: <20180111082452.27295.85707.stgit@pasha-VirtualBox> References: <20180111082452.27295.85707.stgit@pasha-VirtualBox> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 83.149.199.45 Subject: [Qemu-devel] [RFC PATCH v3 15/30] cpus: push BQL lock to qemu_*_wait_io_event X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, pavel.dovgaluk@ispras.ru, mst@redhat.com, jasowang@redhat.com, quintela@redhat.com, zuban32s@gmail.com, maria.klimushenkova@ispras.ru, dovgaluk@ispras.ru, kraxel@redhat.com, boost.lists@gmail.com, pbonzini@redhat.com, alex.bennee@linaro.org Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" From: Alex Bennée We only really need to grab the lock for initial setup (so we don't race with the thread-spawning thread). After that we can drop the lock for the whole main loop and only grab it for waiting for IO events. There is a slight wrinkle for the round-robin TCG thread as we also expire timers which needs to be done under BQL as they are in the main-loop. This is stage one of reducing the lock impact as we can drop the requirement of implicit BQL for async work and only grab the lock when we need to sleep on the cpu->halt_cond. Signed-off-by: Alex Bennée Tested-by: Pavel Dovgalyuk --- accel/kvm/kvm-all.c | 4 ---- cpus.c | 27 ++++++++++++++++++++------- target/i386/hax-all.c | 2 -- 3 files changed, 20 insertions(+), 13 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index f290f48..8d1d2c4 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -1857,9 +1857,7 @@ int kvm_cpu_exec(CPUState *cpu) return EXCP_HLT; } - qemu_mutex_unlock_iothread(); cpu_exec_start(cpu); - do { MemTxAttrs attrs; @@ -1989,8 +1987,6 @@ int kvm_cpu_exec(CPUState *cpu) } while (ret == 0); cpu_exec_end(cpu); - qemu_mutex_lock_iothread(); - if (ret < 0) { cpu_dump_state(cpu, stderr, fprintf, CPU_DUMP_CODE); vm_stop(RUN_STATE_INTERNAL_ERROR); diff --git a/cpus.c b/cpus.c index b4146a8..82dcbf8 100644 --- a/cpus.c +++ b/cpus.c @@ -1149,6 +1149,8 @@ static bool qemu_tcg_should_sleep(CPUState *cpu) static void qemu_tcg_wait_io_event(CPUState *cpu) { + qemu_mutex_lock_iothread(); + while (qemu_tcg_should_sleep(cpu)) { stop_tcg_kick_timer(); qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); @@ -1157,15 +1159,21 @@ static void qemu_tcg_wait_io_event(CPUState *cpu) start_tcg_kick_timer(); qemu_wait_io_event_common(cpu); + + qemu_mutex_unlock_iothread(); } static void qemu_kvm_wait_io_event(CPUState *cpu) { + qemu_mutex_lock_iothread(); + while (cpu_thread_is_idle(cpu)) { qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); } qemu_wait_io_event_common(cpu); + + qemu_mutex_unlock_iothread(); } static void qemu_hvf_wait_io_event(CPUState *cpu) @@ -1199,6 +1207,8 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) /* signal CPU creation */ cpu->created = true; + qemu_mutex_unlock_iothread(); + qemu_cond_signal(&qemu_cpu_cond); do { @@ -1241,10 +1251,10 @@ static void *qemu_dummy_cpu_thread_fn(void *arg) /* signal CPU creation */ cpu->created = true; + qemu_mutex_unlock_iothread(); qemu_cond_signal(&qemu_cpu_cond); while (1) { - qemu_mutex_unlock_iothread(); do { int sig; r = sigwait(&waitset, &sig); @@ -1255,6 +1265,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg) } qemu_mutex_lock_iothread(); qemu_wait_io_event_common(cpu); + qemu_mutex_unlock_iothread(); } return NULL; @@ -1343,11 +1354,9 @@ static int tcg_cpu_exec(CPUState *cpu) #ifdef CONFIG_PROFILER ti = profile_getclock(); #endif - qemu_mutex_unlock_iothread(); cpu_exec_start(cpu); ret = cpu_exec(cpu); cpu_exec_end(cpu); - qemu_mutex_lock_iothread(); #ifdef CONFIG_PROFILER tcg_time += profile_getclock() - ti; #endif @@ -1407,6 +1416,7 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) qemu_wait_io_event_common(cpu); } } + qemu_mutex_unlock_iothread(); start_tcg_kick_timer(); @@ -1416,6 +1426,9 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) cpu->exit_request = 1; while (1) { + + qemu_mutex_lock_iothread(); + /* Account partial waits to QEMU_CLOCK_VIRTUAL. */ qemu_account_warp_timer(); @@ -1424,6 +1437,8 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) */ handle_icount_deadline(); + qemu_mutex_unlock_iothread(); + if (!cpu) { cpu = first_cpu; } @@ -1449,9 +1464,7 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) cpu_handle_guest_debug(cpu); break; } else if (r == EXCP_ATOMIC) { - qemu_mutex_unlock_iothread(); cpu_exec_step_atomic(cpu); - qemu_mutex_lock_iothread(); break; } } else if (cpu->stop) { @@ -1492,6 +1505,7 @@ static void *qemu_hax_cpu_thread_fn(void *arg) current_cpu = cpu; hax_init_vcpu(cpu); + qemu_mutex_unlock_iothread(); qemu_cond_signal(&qemu_cpu_cond); while (1) { @@ -1584,6 +1598,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) cpu->created = true; cpu->can_do_io = 1; current_cpu = cpu; + qemu_mutex_unlock_iothread(); qemu_cond_signal(&qemu_cpu_cond); /* process any pending work */ @@ -1608,9 +1623,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) g_assert(cpu->halted); break; case EXCP_ATOMIC: - qemu_mutex_unlock_iothread(); cpu_exec_step_atomic(cpu); - qemu_mutex_lock_iothread(); default: /* Ignore everything else? */ break; diff --git a/target/i386/hax-all.c b/target/i386/hax-all.c index 3ce6950..9fd60d9 100644 --- a/target/i386/hax-all.c +++ b/target/i386/hax-all.c @@ -513,11 +513,9 @@ static int hax_vcpu_hax_exec(CPUArchState *env) hax_vcpu_interrupt(env); - qemu_mutex_unlock_iothread(); cpu_exec_start(cpu); hax_ret = hax_vcpu_run(vcpu); cpu_exec_end(cpu); - qemu_mutex_lock_iothread(); /* Simply continue the vcpu_run if system call interrupted */ if (hax_ret == -EINTR || hax_ret == -EAGAIN) {