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[68.160.176.52]) by smtp.gmail.com with ESMTPSA id a19-20020ac85b93000000b002e0023473edsm4515100qta.95.2022.03.04.18.14.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Mar 2022 18:14:21 -0800 (PST) Date: Fri, 4 Mar 2022 21:14:21 -0500 From: Mike Snitzer To: Ming Lei Message-ID: References: <20220304212623.34016-1-snitzer@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 X-loop: dm-devel@redhat.com Cc: axboe@kernel.dk, linux-block@vger.kernel.org, dm-devel@redhat.com, hch@lst.de Subject: Re: [dm-devel] [PATCH v4 0/2] block/dm: support bio polling X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, Mar 04 2022 at 8:43P -0500, Ming Lei wrote: > On Fri, Mar 04, 2022 at 04:26:21PM -0500, Mike Snitzer wrote: > > Hi, > > > > I've rebased Ming's latest [1] ontop of dm-5.18 [2] (which is based on > > for-5.18/block). End result available in dm-5.18-biopoll branch [3] > > > > These changes add bio polling support to DM. Tested with linear and > > striped DM targets. > > > > IOPS improvement was ~5% on my baremetal system with a single Intel > > Optane NVMe device (555K hipri=1 vs 525K hipri=0). > > > > Ming has seen better improvement while testing within a VM: > > dm-linear: hipri=1 vs hipri=0 15~20% iops improvement > > dm-stripe: hipri=1 vs hipri=0 ~30% iops improvement > > > > I'd like to merge these changes via the DM tree when the 5.18 merge > > window opens. The first block patch that adds ->poll_bio to > > block_device_operations will need review so that I can take it > > through the DM tree. Reason for going through the DM tree is there > > have been some fairly extensive changes queued in dm-5.18 that build > > on for-5.18/block. So I think it easiest to just add the block > > depenency via DM tree since DM is first consumer of ->poll_bio > > > > FYI, Ming does have another DM patch [4] that looks to avoid using > > hlist but I only just saw it. bio_split() _is_ involved (see > > dm_split_and_process_bio) so I'm not exactly sure where he is going > > with that change. > > io_uring(polling) workloads often cares latency, so big IO request > isn't involved usually, I guess. Then bio_split() is seldom called in > dm_split_and_process_bio(), such as if 4k random IO is run on dm-linear > or dm-stripe via io_uring, bio_split() won't be run into. > > Single list is enough here, and efficient than hlist, just need > a little care to delete element from the list since linux kernel doesn't > have generic single list implementation. OK, makes sense, thanks for clarifying. But yeah its a bit fiddley for sure. > > But that is DM-implementation detail that we'll > > sort out. > > Yeah, that patch also needs more test. Yeap, sounds good. -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel 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 63608C433F5 for ; Sat, 5 Mar 2022 02:14:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230454AbiCECPO (ORCPT ); Fri, 4 Mar 2022 21:15:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229575AbiCECPN (ORCPT ); Fri, 4 Mar 2022 21:15:13 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D32DA1DC9AC for ; Fri, 4 Mar 2022 18:14:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646446464; 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=mQ3j752MT2c0Va4+BHXixIvzPf7SXNYhTYkAyxToXME=; b=fcuNgEXsoc5IQDVoekh0/ln2Jte5HveDlgtizYQt/vwDrr4UM3iM4CudoZe04lfeCvYCLS uzI6cXxzUHgXEfgh1GKZGOXIL2wYrAORrqVz3m6XhH6B398yU1wKDixTpTsXbAgKe0Yi/v TmXUIZ882j9U/ImLdY3H+DPhowAZooU= Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-125-XUjGTAA6NVG8xRSo4qHE2A-1; Fri, 04 Mar 2022 21:14:23 -0500 X-MC-Unique: XUjGTAA6NVG8xRSo4qHE2A-1 Received: by mail-qt1-f199.google.com with SMTP id b3-20020ac84f03000000b002e038c19f71so7647882qte.2 for ; Fri, 04 Mar 2022 18:14:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=mQ3j752MT2c0Va4+BHXixIvzPf7SXNYhTYkAyxToXME=; b=iP2ChZIdlgGuRkjgjUM4Yv/a0qwt2MDP7nZW9od8uK6+fcNVpNa+U9tJCmU30At4XA EDzg7xwQub8N8M9xYw9vyoY2qzuiSdFGgjZaAccYJykpNDdJ9wA5qLgHHwRuX1E/6uV4 VmYushVvwkJZF1JrmKuo73UGwGJol4WL2fq1GrcVWQoeKkbG/xcKG9WmxDsJmqNkskfx CMR0GOHOgBsHLVR0YAXXI15Bc2ChU0EA/Ro09kmkK4+ZOgpMy/KKYLrWFLWvgEvjwkvo eql6MK1bpNlQ4ZBFvXkP1wUsNB1iUMAwqec7Z4TU+V9gihrTRhjOGUGSOY/DvEfTlaTB P6VA== X-Gm-Message-State: AOAM531it9sktrVkqM2UfvrghHtwaAjMhQ6iZFz5hT7JC3I7F1XArsv8 K/j9wLk0B9uvRO9H4Ae3RNBnXUH1CuJs7jicYKp7KSW9GiEY+gaCuE1FIcvHfTgteDavIa01MOb fTzx6jjjYG93s9svEgVFwuw== X-Received: by 2002:ad4:5f0e:0:b0:432:e889:810c with SMTP id fo14-20020ad45f0e000000b00432e889810cmr1361639qvb.37.1646446462506; Fri, 04 Mar 2022 18:14:22 -0800 (PST) X-Google-Smtp-Source: ABdhPJxMC+u1zy14ii7oCjULtwAClNOzsgkoDddDB0O4sbnNOAbYlXBNmZaVvJ/Fj9elFqDGl9rI5Q== X-Received: by 2002:ad4:5f0e:0:b0:432:e889:810c with SMTP id fo14-20020ad45f0e000000b00432e889810cmr1361628qvb.37.1646446462303; Fri, 04 Mar 2022 18:14:22 -0800 (PST) Received: from localhost (pool-68-160-176-52.bstnma.fios.verizon.net. [68.160.176.52]) by smtp.gmail.com with ESMTPSA id a19-20020ac85b93000000b002e0023473edsm4515100qta.95.2022.03.04.18.14.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Mar 2022 18:14:21 -0800 (PST) Date: Fri, 4 Mar 2022 21:14:21 -0500 From: Mike Snitzer To: Ming Lei Cc: axboe@kernel.dk, hch@lst.de, dm-devel@redhat.com, linux-block@vger.kernel.org Subject: Re: [PATCH v4 0/2] block/dm: support bio polling Message-ID: References: <20220304212623.34016-1-snitzer@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Mar 04 2022 at 8:43P -0500, Ming Lei wrote: > On Fri, Mar 04, 2022 at 04:26:21PM -0500, Mike Snitzer wrote: > > Hi, > > > > I've rebased Ming's latest [1] ontop of dm-5.18 [2] (which is based on > > for-5.18/block). End result available in dm-5.18-biopoll branch [3] > > > > These changes add bio polling support to DM. Tested with linear and > > striped DM targets. > > > > IOPS improvement was ~5% on my baremetal system with a single Intel > > Optane NVMe device (555K hipri=1 vs 525K hipri=0). > > > > Ming has seen better improvement while testing within a VM: > > dm-linear: hipri=1 vs hipri=0 15~20% iops improvement > > dm-stripe: hipri=1 vs hipri=0 ~30% iops improvement > > > > I'd like to merge these changes via the DM tree when the 5.18 merge > > window opens. The first block patch that adds ->poll_bio to > > block_device_operations will need review so that I can take it > > through the DM tree. Reason for going through the DM tree is there > > have been some fairly extensive changes queued in dm-5.18 that build > > on for-5.18/block. So I think it easiest to just add the block > > depenency via DM tree since DM is first consumer of ->poll_bio > > > > FYI, Ming does have another DM patch [4] that looks to avoid using > > hlist but I only just saw it. bio_split() _is_ involved (see > > dm_split_and_process_bio) so I'm not exactly sure where he is going > > with that change. > > io_uring(polling) workloads often cares latency, so big IO request > isn't involved usually, I guess. Then bio_split() is seldom called in > dm_split_and_process_bio(), such as if 4k random IO is run on dm-linear > or dm-stripe via io_uring, bio_split() won't be run into. > > Single list is enough here, and efficient than hlist, just need > a little care to delete element from the list since linux kernel doesn't > have generic single list implementation. OK, makes sense, thanks for clarifying. But yeah its a bit fiddley for sure. > > But that is DM-implementation detail that we'll > > sort out. > > Yeah, that patch also needs more test. Yeap, sounds good.