From patchwork Tue Oct 31 10:48:46 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 117558 Delivered-To: patch@linaro.org Received: by 10.80.245.45 with SMTP id t42csp3795078edm; Tue, 31 Oct 2017 03:54:38 -0700 (PDT) X-Google-Smtp-Source: ABhQp+T36s1IcxRkIRnRzRRVRJUeqIdKCgMSu0M8Yikr41frDMSv1pQ8jKdtYpoofbd0X4HaWzSo X-Received: by 10.129.102.8 with SMTP id a8mr890377ywc.304.1509447278253; Tue, 31 Oct 2017 03:54:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1509447278; cv=none; d=google.com; s=arc-20160816; b=HH0kzH93Uefhf6hpSwDNWci2Z4TKYJo/U8qPAHFVfAW8QORVkKSl9U3bCHWegFb1NZ uD0XBymbdrbg0+OKXF00N7Skchrf/F9yCEyjYpOp8AsY6TO91dBBtY5WIxrqakAW/44v DFQBxuePYsVWJwfxeu203chLWMLP+qM96UpGh3Edw6JWXVCANhqMCOb7lGn7wV//1Lg1 WJYYpfiIl+9bi+4AQ4EtjS0Vqhxd3s8czidowL4yPvTiCkuCvF8Qd+RzCtisYsI7iVaF 9aPKYGs2tCnZX770Tsqm0AbS6AqwwICT4PWSZ6mNrd8a5BOilYRaS8nHHkodj3OjcBln PDvQ== 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=Xq3oexLI0hAc9hcFcbs755THdfSatWHCu4Yg7p6UEj8=; b=LzIG4klY1+qsIQnOWn5trj8iaB7bMMcDlAyNUB9Wh8yXOF/mmxuSYJY0B/eRmFRzjq LbMTNY0YYpvlS2Gs4d1BVeuKSiVIj/CSxyA4LCAeVqRBpZsfCGNHPM7G3EtGEmgNJz08 9Y0fgYdY4qNz9npyvpeZ+OYFUVSve1n0n0inSm7kazFNp10cCEIj7JAUTQHkWuBxtLRT MiUVumqg7cuPraKEkP1MpYfXQdHwTIEa3S/sA8j4r2m7VEOJBxKs4+pyzpk9ip/xCCRs Zwp/mQnxvU3+5MhWmRsUym/9SLXzaSHwZEiUI+qDNFTN+Hc7c2asTb9la2bln5wGLgF1 Siew== 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 p137si367042ywe.567.2017.10.31.03.54.38 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 31 Oct 2017 03:54:38 -0700 (PDT) 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]:44715 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e9UBp-0002M0-Ki for patch@linaro.org; Tue, 31 Oct 2017 06:54:37 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57977) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e9U6B-00065c-Os for qemu-devel@nongnu.org; Tue, 31 Oct 2017 06:48:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e9U6A-0004kx-De for qemu-devel@nongnu.org; Tue, 31 Oct 2017 06:48:47 -0400 Received: from mail.ispras.ru ([83.149.199.45]:39948) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e9U6A-0004jV-1e for qemu-devel@nongnu.org; Tue, 31 Oct 2017 06:48:46 -0400 Received: from [127.0.1.1] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id 51E5254006A; Tue, 31 Oct 2017 13:48:45 +0300 (MSK) From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Tue, 31 Oct 2017 13:48:46 +0300 Message-ID: <20171031104846.3079.43409.stgit@pasha-VirtualBox> In-Reply-To: <20171031104741.3079.26584.stgit@pasha-VirtualBox> References: <20171031104741.3079.26584.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] [RFCPATCH12/20] 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: dovgaluk@ispras.ru 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 Signed-off-by: Pavel Dovgalyuk --- accel/kvm/kvm-all.c | 4 ---- cpus.c | 27 ++++++++++++++++++++------- target/i386/hax-all.c | 3 +-- 3 files changed, 21 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 2eec54f..efde5c1 100644 --- a/cpus.c +++ b/cpus.c @@ -1127,6 +1127,8 @@ 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); @@ -1135,15 +1137,21 @@ 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_kvm_cpu_thread_fn(void *arg) @@ -1169,6 +1177,8 @@ 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 { @@ -1211,10 +1221,10 @@ 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); @@ -1225,6 +1235,7 @@ 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; @@ -1313,11 +1324,9 @@ 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 @@ -1377,6 +1386,7 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) qemu_wait_io_event_common(cpu); } } + qemu_mutex_unlock_iothread(); start_tcg_kick_timer(); @@ -1386,6 +1396,9 @@ 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(); @@ -1394,6 +1407,8 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) */ handle_icount_deadline(); + qemu_mutex_unlock_iothread(); + if (!cpu) { cpu = first_cpu; } @@ -1419,9 +1434,7 @@ 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) { @@ -1462,6 +1475,7 @@ 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) { @@ -1512,6 +1526,7 @@ 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 */ @@ -1536,9 +1551,7 @@ 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..99af6bb 100644 --- a/target/i386/hax-all.c +++ b/target/i386/hax-all.c @@ -513,11 +513,10 @@ 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); + current_cpu = cpu; cpu_exec_end(cpu); - qemu_mutex_lock_iothread(); /* Simply continue the vcpu_run if system call interrupted */ if (hax_ret == -EINTR || hax_ret == -EAGAIN) {