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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 838EFC433DF for ; Wed, 24 Jun 2020 22:59:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5BD7F2073E for ; Wed, 24 Jun 2020 22:59:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Cbfi8SVs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388104AbgFXW7O (ORCPT ); Wed, 24 Jun 2020 18:59:14 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:33723 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728383AbgFXW7O (ORCPT ); Wed, 24 Jun 2020 18:59:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593039551; 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=xEPXGmRuXy84KM2mPCdo3BbJP27cNaBu5OvOVstsHYQ=; b=Cbfi8SVser10PUA2aEWjKG61pz1z8e3YWWxrP1ehbgFbRQvIntmWkC5suzT2Ear3LKpw74 oiavk7MQW42daHkTab0McT5giEsjIVMxDWgvRhjE0847DRUa8HByeL1brpmHyw5hkGkJAJ 5eDamgLKF0a+LFUeJY1jO5NLoHU9MAA= 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-312-wp9i3H1IPP6lKFQh4t36gA-1; Wed, 24 Jun 2020 18:59:07 -0400 X-MC-Unique: wp9i3H1IPP6lKFQh4t36gA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EBD65804001; Wed, 24 Jun 2020 22:59:05 +0000 (UTC) Received: from T590 (ovpn-12-22.pek2.redhat.com [10.72.12.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E97CD82026; Wed, 24 Jun 2020 22:58:59 +0000 (UTC) Date: Thu, 25 Jun 2020 06:58:55 +0800 From: Ming Lei To: Sagi Grimberg Cc: Jens Axboe , linux-block@vger.kernel.org, Damien Le Moal , Baolin Wang , Christoph Hellwig Subject: Re: [PATCH V5 0/6] blk-mq: support batching dispatch from scheduler Message-ID: <20200624225855.GA1045898@T590> References: <20200603094337.2064181-1-ming.lei@redhat.com> <4c5d8c1b-2b5a-1bee-b5eb-5f4b7336b979@grimberg.me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4c5d8c1b-2b5a-1bee-b5eb-5f4b7336b979@grimberg.me> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Jun 24, 2020 at 02:17:28PM -0700, Sagi Grimberg wrote: > > > Hi Jens, > > > > 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%. > > > > Baolin has tested previous versions and found performance on MMC can be improved. > > > > Patch 1 ~ 4 are improvement and cleanup, which can't applied without > > supporting batching dispatch. > > > > Patch 5 ~ 6 starts to support batching dispatch from scheduler. > > > > > > > > [1] https://lore.kernel.org/linux-block/20200512075501.GF1531898@T590/#r > > [2] https://lore.kernel.org/linux-block/fe6bd8b9-6ed9-b225-f80c-314746133722@grimberg.me/ > > > > V5: > > - code style changes suggested by Damien > > > > V4: > > - fix releasing budgets and avoids IO hang(5/6) > > - dispatch more batches if the device can accept more(6/6) > > - verified by running more tests > > > > V3: > > - add reviewed-by tag > > - fix one typo > > - fix one budget leak issue in case that .queue_rq returned *_RESOURCE in 5/6 > > > > V2: > > - remove 'got_budget' from blk_mq_dispatch_rq_list > > - drop patch for getting driver tag & handling partial dispatch > > Hey Ming, > > What ever happened to this one? Hi Sagi, Looks the 1st patch can't be applied cleanly against for-5.9/block, I will send V6 later. thanks, Ming