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 X-Spam-Level: X-Spam-Status: No, score=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCCF5C433DB for ; Tue, 19 Jan 2021 04:09:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 809A920DD4 for ; Tue, 19 Jan 2021 04:09:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730573AbhASEJC (ORCPT ); Mon, 18 Jan 2021 23:09:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:24592 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730116AbhASEIN (ORCPT ); Mon, 18 Jan 2021 23:08:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611029204; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XxjUqcN38hjRWlI1UqqG9yx1inb5rkEhsdJ3OcF1xYs=; b=eGeY2KN2eBbq0SSlaqOv8AWppqYCmKBf4UUW/eOnVnurWPOjsjin3FmpUuF9LpWxHg93x5 eVbxMU2ul8EqnXT5uo+mCQyl1jDwAdeHg/Sg0zccJosk9qDr0hLErNNYiwpTkJyGo1G1pH siplLxY8LB8OfVgSclZYIwqrUB3+Urw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-271-peZjWp4XPnOEOApiswON6g-1; Mon, 18 Jan 2021 23:06:42 -0500 X-MC-Unique: peZjWp4XPnOEOApiswON6g-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 35B6515723; Tue, 19 Jan 2021 04:06:41 +0000 (UTC) Received: from [10.72.13.139] (ovpn-13-139.pek2.redhat.com [10.72.13.139]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4197B62688; Tue, 19 Jan 2021 04:06:35 +0000 (UTC) Subject: Re: [PATCH RFC] virtio-blk: support per-device queue depth To: JeffleXu , Joseph Qi , "Michael S. Tsirkin" Cc: virtualization@lists.linux-foundation.org, linux-block@vger.kernel.org References: <1610942338-78252-1-git-send-email-joseph.qi@linux.alibaba.com> <4141645d-6dfc-110c-bfcd-03641df8332c@linux.alibaba.com> From: Jason Wang Message-ID: <46f2f81f-9906-e1f7-d8fd-6da2c61683ba@redhat.com> Date: Tue, 19 Jan 2021 12:06:34 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <4141645d-6dfc-110c-bfcd-03641df8332c@linux.alibaba.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2021/1/19 上午9:33, JeffleXu wrote: > > On 1/18/21 1:25 PM, Jason Wang wrote: >> On 2021/1/18 上午11:58, Joseph Qi wrote: >>> module parameter 'virtblk_queue_depth' was firstly introduced for >>> testing/benchmarking purposes described in commit fc4324b4597c >>> ("virtio-blk: base queue-depth on virtqueue ringsize or module param"). >>> Since we have different virtio-blk devices which have different >>> capabilities, it requires that we support per-device queue depth instead >>> of per-module. So defaultly use vq free elements if module parameter >>> 'virtblk_queue_depth' is not set. >> >> I wonder if it's better to use sysfs instead (or whether it has already >> had something like this in the blocker layer). >> > "/sys/block//queue/nr_requests" indeed works, but isn't better to > set queue_depth according to the hardware capability at the very first? > AFAIK, nvme just set per-device queue_depth at initializing phase. I agree, the problem is that the current code may modify module parameter. Thanks > > Thanks, > Jeffle > >> >>> Signed-off-by: Joseph Qi >>> --- >>>   drivers/block/virtio_blk.c | 12 +++++++----- >>>   1 file changed, 7 insertions(+), 5 deletions(-) >>> >>> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c >>> index 145606d..f83a417 100644 >>> --- a/drivers/block/virtio_blk.c >>> +++ b/drivers/block/virtio_blk.c >>> @@ -705,6 +705,7 @@ static int virtblk_probe(struct virtio_device *vdev) >>>       u32 v, blk_size, max_size, sg_elems, opt_io_size; >>>       u16 min_io_size; >>>       u8 physical_block_exp, alignment_offset; >>> +    unsigned int queue_depth; >>>         if (!vdev->config->get) { >>>           dev_err(&vdev->dev, "%s failure: config access disabled\n", >>> @@ -755,17 +756,18 @@ static int virtblk_probe(struct virtio_device >>> *vdev) >>>           goto out_free_vq; >>>       } >>>   -    /* Default queue sizing is to fill the ring. */ >>> -    if (!virtblk_queue_depth) { >>> -        virtblk_queue_depth = vblk->vqs[0].vq->num_free; >>> +    if (likely(!virtblk_queue_depth)) { >>> +        queue_depth = vblk->vqs[0].vq->num_free; >>>           /* ... but without indirect descs, we use 2 descs per req */ >>>           if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) >>> -            virtblk_queue_depth /= 2; >>> +            queue_depth /= 2; >>> +    } else { >>> +        queue_depth = virtblk_queue_depth; >>>       } >>>         memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); >>>       vblk->tag_set.ops = &virtio_mq_ops; >>> -    vblk->tag_set.queue_depth = virtblk_queue_depth; >>> +    vblk->tag_set.queue_depth = queue_depth; >>>       vblk->tag_set.numa_node = NUMA_NO_NODE; >>>       vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; >>>       vblk->tag_set.cmd_size =