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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A2BFC433F5 for ; Wed, 9 Mar 2022 01:26:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230100AbiCIB1b (ORCPT ); Tue, 8 Mar 2022 20:27:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230360AbiCIB13 (ORCPT ); Tue, 8 Mar 2022 20:27:29 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9F7E39A4FD for ; Tue, 8 Mar 2022 17:26:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646789180; 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=lNIylrZM6unomlwJxnnl1YZ92D1gofy+4LkRW9aVRNU=; b=aCH57uVLof3GXQurEfzVgJUwCbwH22Odfd79eH7Gq+S4OxAdBgHy8yhO9s8rYs34XvphvZ i/0LE51umd11Hxhbtt9WImQL4opy8lehgLTVq5ZrrIBANma6pOsI2dUE6mFw2stTWSj2kB RxFyfc0Ray935aPskaMXldoXcvpqoO4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-580-DxdcWgDMNOyeZNnxbyPgqw-1; Tue, 08 Mar 2022 20:14:12 -0500 X-MC-Unique: DxdcWgDMNOyeZNnxbyPgqw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AE9012F35; Wed, 9 Mar 2022 01:14:11 +0000 (UTC) Received: from T590 (ovpn-8-34.pek2.redhat.com [10.72.8.34]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 726415D986; Wed, 9 Mar 2022 01:13:35 +0000 (UTC) Date: Wed, 9 Mar 2022 09:13:30 +0800 From: Ming Lei To: Jens Axboe Cc: Mike Snitzer , hch@lst.de, dm-devel@redhat.com, linux-block@vger.kernel.org Subject: Re: [PATCH v6 2/2] dm: support bio polling Message-ID: References: <20220307185303.71201-1-snitzer@redhat.com> <20220307185303.71201-3-snitzer@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Mar 08, 2022 at 06:02:50PM -0700, Jens Axboe wrote: > On 3/7/22 11:53 AM, Mike Snitzer wrote: > > From: Ming Lei > > > > Support bio(REQ_POLLED) polling in the following approach: > > > > 1) only support io polling on normal READ/WRITE, and other abnormal IOs > > still fallback to IRQ mode, so the target io is exactly inside the dm > > io. > > > > 2) hold one refcnt on io->io_count after submitting this dm bio with > > REQ_POLLED > > > > 3) support dm native bio splitting, any dm io instance associated with > > current bio will be added into one list which head is bio->bi_private > > which will be recovered before ending this bio > > > > 4) implement .poll_bio() callback, call bio_poll() on the single target > > bio inside the dm io which is retrieved via bio->bi_bio_drv_data; call > > dm_io_dec_pending() after the target io is done in .poll_bio() > > > > 5) enable QUEUE_FLAG_POLL if all underlying queues enable QUEUE_FLAG_POLL, > > which is based on Jeffle's previous patch. > > It's not the prettiest thing in the world with the overlay on bi_private, > but at least it's nicely documented now. > > I would encourage you to actually test this on fast storage, should make > a nice difference. I can run this on a gen2 optane, it's 10x the IOPS > of what it was tested on and should help better highlight where it > makes a difference. > > If either of you would like that, then send me a fool proof recipe for > what should be setup so I have a poll capable dm device. Follows steps for setup dm stripe over two nvmes, then run io_uring on the dm stripe dev. 1) dm_stripe.perl #!/usr/bin/perl -w # Create a striped device across any number of underlying devices. The device # will be called "stripe_dev" and have a chunk-size of 128k. my $chunk_size = 128 * 2; my $dev_name = "stripe_dev"; my $num_devs = @ARGV; my @devs = @ARGV; my ($min_dev_size, $stripe_dev_size, $i); if (!$num_devs) { die("Specify at least one device\n"); } $min_dev_size = `blockdev --getsz $devs[0]`; for ($i = 1; $i < $num_devs; $i++) { my $this_size = `blockdev --getsz $devs[$i]`; $min_dev_size = ($min_dev_size < $this_size) ? $min_dev_size : $this_size; } $stripe_dev_size = $min_dev_size * $num_devs; $stripe_dev_size -= $stripe_dev_size % ($chunk_size * $num_devs); $table = "0 $stripe_dev_size striped $num_devs $chunk_size"; for ($i = 0; $i < $num_devs; $i++) { $table .= " $devs[$i] 0"; } `echo $table | dmsetup create $dev_name`; 2) test_poll_on_dm_stripe.sh #!/bin/bash RT=40 JOBS=1 HI=1 BS=4K set -x dmsetup remove_all rmmod nvme modprobe nvme poll_queues=2 sleep 2 ./dm_stripe.perl /dev/nvme0n1 /dev/nvme1n1 sleep 1 DEV=/dev/mapper/stripe_dev echo "io_uring hipri test" fio --bs=$BS --ioengine=io_uring --fixedbufs --registerfiles \ --hipri=$HI --iodepth=64 --iodepth_batch_submit=16 --iodepth_batch_complete_min=16 \ --filename=$DEV --direct=1 --runtime=$RT --numjobs=$JOBS --rw=randread --name=test \ --group_reporting Thanks, Ming