From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 02E8E1851 for ; Fri, 8 Dec 2023 02:00:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hoODj/Gp" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1702000853; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=JJ2EPKnJQm+fAlvkL+74UAK/7dPrJSHeWEZnkUKYj2w=; b=hoODj/GpmV6n+LHdFGuoT0K2OwpfWxKAPZzdinb/mQ08AjQivQih7wgDcbJalr1yOmGa03 kfvw2fxmU9ORU7Bh+/0KkTb7VTlu7w6LO1eUxm2L9dXgAPf+XneCrK2TQ+Wt4LOtmRbSen 86xktPKNH4hCd4cjbAL/ipf1Fy9VphM= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-662-Fz9at8PFNQ-bnMhti6X8PQ-1; Thu, 07 Dec 2023 21:00:48 -0500 X-MC-Unique: Fz9at8PFNQ-bnMhti6X8PQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D6E0C3C10153; Fri, 8 Dec 2023 02:00:47 +0000 (UTC) Received: from fedora (unknown [10.72.120.10]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 991062026D66; Fri, 8 Dec 2023 02:00:41 +0000 (UTC) Date: Fri, 8 Dec 2023 10:00:36 +0800 From: Ming Lei To: Li Feng Cc: Jens Axboe , "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Xuan Zhuo , "open list:BLOCK LAYER" , open list , "open list:VIRTIO BLOCK AND SCSI DRIVERS" Subject: Re: [PATCH] virtio_blk: set the default scheduler to none Message-ID: References: <20231207043118.118158-1-fengli@smartx.com> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231207043118.118158-1-fengli@smartx.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.4 On Thu, Dec 07, 2023 at 12:31:05PM +0800, Li Feng wrote: > virtio-blk is generally used in cloud computing scenarios, where the > performance of virtual disks is very important. The mq-deadline scheduler > has a big performance drop compared to none with single queue. In my tests, > mq-deadline 4k readread iops were 270k compared to 450k for none. So here > the default scheduler of virtio-blk is set to "none". The test result shows you may not test HDD. backing of virtio-blk. none can lose IO merge capability more or less, so probably sequential IO perf drops in case of HDD backing. Thanks, Ming