From mboxrd@z Thu Jan 1 00:00:00 1970 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 CDB14C433EF for ; Wed, 15 Jun 2022 16:09:32 +0000 (UTC) Received: from localhost ([::1]:33560 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o1VaF-0003X1-SY for qemu-devel@archiver.kernel.org; Wed, 15 Jun 2022 12:09:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43094) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o1VLh-0003tX-V8 for qemu-devel@nongnu.org; Wed, 15 Jun 2022 11:54:29 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:20978) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o1VLd-0007HP-SQ for qemu-devel@nongnu.org; Wed, 15 Jun 2022 11:54:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655308462; 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=oXloEW1UlhTVt+kWsYE9sTdp9W652tVKcmcqc754vL4=; b=XYrmIlv847gKG/b89UTTtOd4DnIJ2nAi596gWWawAW3E6MzVMYxEJcwTjtEna0B8YJrGX1 +tUVidpdseL+G0uJPy/79QqX9o8xFkFqtt9pz4YV4d+mYLq9iWkqQWFfbp95P5ZaYRBJex v4pczuLBsz2qCxS9KNk2JZFYfdJusOk= 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-32--28FBiW3MS2IuYOa1M0_cA-1; Wed, 15 Jun 2022 11:54:18 -0400 X-MC-Unique: -28FBiW3MS2IuYOa1M0_cA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 922E480B70A; Wed, 15 Jun 2022 15:54:16 +0000 (UTC) Received: from localhost (unknown [10.39.192.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2EF221415107; Wed, 15 Jun 2022 15:54:16 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Thomas Huth , Jagannathan Raman , Aarushi Mehta , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Elena Ufimtseva , Marcel Apfelbaum , Stefan Hajnoczi , Laurent Vivier , , "Dr. David Alan Gilbert" , Richard Henderson , virtio-fs@redhat.com, Hanna Reitz , David Hildenbrand , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Eric Blake , Kevin Wolf , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Beraldo Leal , Peter Xu , Eduardo Habkost , Qiuhao Li , Paolo Bonzini , Markus Armbruster , Bandan Das , "Michael S. Tsirkin" , Stefano Garzarella , Alexander Bulekov , Julia Suvorova , Darren Kenny , Wainer dos Santos Moschetta , John G Johnson , Sam Li Subject: [PULL 02/18] Use io_uring_register_ring_fd() to skip fd operations Date: Wed, 15 Jun 2022 16:51:13 +0100 Message-Id: <20220615155129.1025811-3-stefanha@redhat.com> In-Reply-To: <20220615155129.1025811-1-stefanha@redhat.com> References: <20220615155129.1025811-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 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_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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: Sam Li Linux recently added a new io_uring(7) optimization API that QEMU doesn't take advantage of yet. The liburing library that QEMU uses has added a corresponding new API calling io_uring_register_ring_fd(). When this API is called after creating the ring, the io_uring_submit() library function passes a flag to the io_uring_enter(2) syscall allowing it to skip the ring file descriptor fdget()/fdput() operations. This saves some CPU cycles. Signed-off-by: Sam Li Message-id: 20220531105011.111082-1-faithilikerun@gmail.com Signed-off-by: Stefan Hajnoczi --- meson.build | 1 + block/io_uring.c | 12 +++++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/meson.build b/meson.build index 0c2e11ff07..9e65cc5367 100644 --- a/meson.build +++ b/meson.build @@ -1752,6 +1752,7 @@ config_host_data.set('CONFIG_LIBNFS', libnfs.found()) config_host_data.set('CONFIG_LIBSSH', libssh.found()) config_host_data.set('CONFIG_LINUX_AIO', libaio.found()) config_host_data.set('CONFIG_LINUX_IO_URING', linux_io_uring.found()) +config_host_data.set('CONFIG_LIBURING_REGISTER_RING_FD', cc.has_function('io_uring_register_ring_fd', prefix: '#include ', dependencies:linux_io_uring)) config_host_data.set('CONFIG_LIBPMEM', libpmem.found()) config_host_data.set('CONFIG_NUMA', numa.found()) config_host_data.set('CONFIG_OPENGL', opengl.found()) diff --git a/block/io_uring.c b/block/io_uring.c index 0b401512b9..d48e472e74 100644 --- a/block/io_uring.c +++ b/block/io_uring.c @@ -18,6 +18,7 @@ #include "qapi/error.h" #include "trace.h" + /* io_uring ring size */ #define MAX_ENTRIES 128 @@ -434,8 +435,17 @@ LuringState *luring_init(Error **errp) } ioq_init(&s->io_q); +#ifdef CONFIG_LIBURING_REGISTER_RING_FD + if (io_uring_register_ring_fd(&s->ring) < 0) { + /* + * Only warn about this error: we will fallback to the non-optimized + * io_uring operations. + */ + warn_report("failed to register linux io_uring ring file descriptor"); + } +#endif + return s; - } void luring_cleanup(LuringState *s) -- 2.36.1