From patchwork Mon Oct 10 09:11:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13002388 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 66697C4332F for ; Mon, 10 Oct 2022 09:34:51 +0000 (UTC) Received: from localhost ([::1]:52662 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ohpBS-0001NI-Cb for qemu-devel@archiver.kernel.org; Mon, 10 Oct 2022 05:34:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41936) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ohop8-0003Yy-H7 for qemu-devel@nongnu.org; Mon, 10 Oct 2022 05:11:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:41047) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ohoot-0000zG-Vo for qemu-devel@nongnu.org; Mon, 10 Oct 2022 05:11:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665393091; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=B/e+RNde4GkseH2SRbguPdqx7kW6xb1u+vAHPNOmPpw=; b=Q8zXry9r76cHuAHqq8wjRJoubsHUmSCrfeGwmGMLrPBgm441VkXXuoDR5UX1i3cqkJwhhe itPZzYPeFYfAsml0ny8jV1CiqqzpORdNU9d0hKiDshQ0ReP/8tlp3HQ+pCVxryPyRWmrsF 5ixdYuHBJE7R/vMkHcE9QL/vg5UwHwU= 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-449-LHlKsqX3OliZeYH0BNI0HQ-1; Mon, 10 Oct 2022 05:11:28 -0400 X-MC-Unique: LHlKsqX3OliZeYH0BNI0HQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CE54D95D687; Mon, 10 Oct 2022 09:11:27 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.119]) by smtp.corp.redhat.com (Postfix) with ESMTP id 114FC1121314; Mon, 10 Oct 2022 09:11:24 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , Michal Privoznik , Igor Mammedov , "Michael S. Tsirkin" , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Dr . David Alan Gilbert" , Eric Blake , Markus Armbruster , Richard Henderson , Stefan Weil Subject: [PATCH v2 2/7] util: Introduce qemu_thread_set_affinity() and qemu_thread_get_affinity() Date: Mon, 10 Oct 2022 11:11:12 +0200 Message-Id: <20221010091117.88603-3-david@redhat.com> In-Reply-To: <20221010091117.88603-1-david@redhat.com> References: <20221010091117.88603-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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 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" Usually, we let upper layers handle CPU pinning, because pthread_setaffinity_np() (-> sched_setaffinity()) is blocked via seccomp when starting QEMU with -sandbox enable=on,resourcecontrol=deny However, we want to configure and observe the CPU affinity of threads from QEMU directly in some cases when the sandbox option is either not enabled or not active yet. So let's add a way to configure CPU pinning via qemu_thread_set_affinity() and obtain CPU affinity via qemu_thread_get_affinity() and implement them under POSIX using pthread_setaffinity_np() + pthread_getaffinity_np(). Implementation under Windows is possible using SetProcessAffinityMask() + GetProcessAffinityMask(), however, that is left as future work. Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand --- include/qemu/thread.h | 4 +++ meson.build | 16 +++++++++ util/qemu-thread-posix.c | 70 ++++++++++++++++++++++++++++++++++++++++ util/qemu-thread-win32.c | 12 +++++++ 4 files changed, 102 insertions(+) diff --git a/include/qemu/thread.h b/include/qemu/thread.h index af19f2b3fc..79e507c7f0 100644 --- a/include/qemu/thread.h +++ b/include/qemu/thread.h @@ -185,6 +185,10 @@ void qemu_event_destroy(QemuEvent *ev); void qemu_thread_create(QemuThread *thread, const char *name, void *(*start_routine)(void *), void *arg, int mode); +int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus, + unsigned long nbits); +int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus, + unsigned long *nbits); void *qemu_thread_join(QemuThread *thread); void qemu_thread_get_self(QemuThread *thread); bool qemu_thread_is_self(QemuThread *thread); diff --git a/meson.build b/meson.build index b686dfef75..3e0aa4925d 100644 --- a/meson.build +++ b/meson.build @@ -2114,7 +2114,23 @@ config_host_data.set('CONFIG_PTHREAD_CONDATTR_SETCLOCK', cc.links(gnu_source_pre pthread_condattr_setclock(&attr, CLOCK_MONOTONIC); return 0; }''', dependencies: threads)) +config_host_data.set('CONFIG_PTHREAD_AFFINITY_NP', cc.links(gnu_source_prefix + ''' + #include + static void *f(void *p) { return NULL; } + int main(void) + { + int setsize = CPU_ALLOC_SIZE(64); + pthread_t thread; + cpu_set_t *cpuset; + pthread_create(&thread, 0, f, 0); + cpuset = CPU_ALLOC(64); + CPU_ZERO_S(setsize, cpuset); + pthread_setaffinity_np(thread, setsize, cpuset); + pthread_getaffinity_np(thread, setsize, cpuset); + CPU_FREE(cpuset); + return 0; + }''', dependencies: threads)) config_host_data.set('CONFIG_SIGNALFD', cc.links(gnu_source_prefix + ''' #include #include diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c index ac1d56e673..bae938c670 100644 --- a/util/qemu-thread-posix.c +++ b/util/qemu-thread-posix.c @@ -16,6 +16,7 @@ #include "qemu/notify.h" #include "qemu-thread-common.h" #include "qemu/tsan.h" +#include "qemu/bitmap.h" static bool name_threads; @@ -552,6 +553,75 @@ void qemu_thread_create(QemuThread *thread, const char *name, pthread_attr_destroy(&attr); } +int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus, + unsigned long nbits) +{ +#if defined(CONFIG_PTHREAD_AFFINITY_NP) + const size_t setsize = CPU_ALLOC_SIZE(nbits); + unsigned long value; + cpu_set_t *cpuset; + int err; + + cpuset = CPU_ALLOC(nbits); + g_assert(cpuset); + + CPU_ZERO_S(setsize, cpuset); + value = find_first_bit(host_cpus, nbits); + while (value < nbits) { + CPU_SET_S(value, setsize, cpuset); + value = find_next_bit(host_cpus, nbits, value + 1); + } + + err = pthread_setaffinity_np(thread->thread, setsize, cpuset); + CPU_FREE(cpuset); + return err; +#else + return -ENOSYS; +#endif +} + +int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus, + unsigned long *nbits) +{ +#if defined(CONFIG_PTHREAD_AFFINITY_NP) + unsigned long tmpbits; + cpu_set_t *cpuset; + size_t setsize; + int i, err; + + tmpbits = CPU_SETSIZE; + while (true) { + setsize = CPU_ALLOC_SIZE(tmpbits); + cpuset = CPU_ALLOC(tmpbits); + g_assert(cpuset); + + err = pthread_getaffinity_np(thread->thread, setsize, cpuset); + if (err) { + CPU_FREE(cpuset); + if (err != -EINVAL) { + return err; + } + tmpbits *= 2; + } else { + break; + } + } + + /* Convert the result into a proper bitmap. */ + *nbits = tmpbits; + *host_cpus = bitmap_new(tmpbits); + for (i = 0; i < tmpbits; i++) { + if (CPU_ISSET(i, cpuset)) { + set_bit(i, *host_cpus); + } + } + CPU_FREE(cpuset); + return 0; +#else + return -ENOSYS; +#endif +} + void qemu_thread_get_self(QemuThread *thread) { thread->thread = pthread_self(); diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c index a2d5a6e825..72338148bd 100644 --- a/util/qemu-thread-win32.c +++ b/util/qemu-thread-win32.c @@ -427,6 +427,18 @@ void qemu_thread_create(QemuThread *thread, const char *name, thread->data = data; } +int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus, + unsigned long nbits) +{ + return -ENOSYS; +} + +int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus, + unsigned long *nbits) +{ + return -ENOSYS; +} + void qemu_thread_get_self(QemuThread *thread) { thread->data = qemu_thread_data;