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=-5.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 DA348C433DF for ; Mon, 25 May 2020 02:17:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B89A92075F for ; Mon, 25 May 2020 02:17:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XUAgFz22" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388425AbgEYCRb (ORCPT ); Sun, 24 May 2020 22:17:31 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:53993 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388308AbgEYCRa (ORCPT ); Sun, 24 May 2020 22:17:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590373049; 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=dXtO9SiCIkTUFllKfzseidfZIN6SrD/bEaYRbu6d+QU=; b=XUAgFz222DYFphHjtL0SZLcGohb0SMcDcf44iMlGOXV7Mb6o03HtEyGNhmJmQgjh6TR5KQ ZIhBkjE3+VX+uNbzO7ee523gixzavto0Szx9td095FrQqZ4ms5IG2nE0eJpYcxs1RwzuoB ayYStpaIiw++du9kzd3BCwaNnvTJ7OQ= 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-56-wV56Q89lPvyIleJu64mK5Q-1; Sun, 24 May 2020 22:17:26 -0400 X-MC-Unique: wV56Q89lPvyIleJu64mK5Q-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C5AE71005510; Mon, 25 May 2020 02:17:24 +0000 (UTC) Received: from T590 (ovpn-13-214.pek2.redhat.com [10.72.13.214]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2456310013C1; Mon, 25 May 2020 02:17:18 +0000 (UTC) Date: Mon, 25 May 2020 10:17:14 +0800 From: Ming Lei To: Baolin Wang Cc: Jens Axboe , linux-block , Sagi Grimberg , Christoph Hellwig Subject: Re: [PATCH 0/9] blk-mq: support batching dispatch from scheduler Message-ID: <20200525021714.GA791214@T590> References: <20200513095443.2038859-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Sat, May 23, 2020 at 03:45:55PM +0800, Baolin Wang wrote: > Hi Ming, > > On Wed, May 13, 2020 at 5:55 PM Ming Lei wrote: > > > > Hi Guys, > > > > More and more drivers want to get batching requests queued from > > block layer, such as mmc[1], and tcp based storage drivers[2]. Also > > current in-tree users have virtio-scsi, virtio-blk and nvme. > > > > For none, we already support batching dispatch. > > > > But for io scheduler, every time we just take one request from scheduler > > and pass the single request to blk_mq_dispatch_rq_list(). This way makes > > batching dispatch not possible when io scheduler is applied. One reason > > is that we don't want to hurt sequential IO performance, becasue IO > > merge chance is reduced if more requests are dequeued from scheduler > > queue. > > > > Tries to start the support by dequeuing more requests from scheduler > > if budget is enough and device isn't busy. > > > > Simple fio test over virtio-scsi shows IO can get improved by 5~10%. > > > > Patches can be found from the following tree too: > > > > https://github.com/ming1/linux/commits/v5.7-rc-blk-mq-batching-submission > > > > Patch 1 ~ 7 are improvement and cleanup, which can't applied without > > supporting batching dispatch. > > > > Patch 8 ~ 9 starts to support batching dispatch from scheduler. > > Sorry for late reply. I've tested your patch set and got some better > performance. Thanks. > Tested-by: Baolin Wang Hi Baolin, Thanks for your test & feedback, then looks this approach is good. I will address comments on v1 and post v2 soon. Thanks, Ming