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 14DD1C433F5 for ; Fri, 11 Mar 2022 16:59:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350413AbiCKRAW (ORCPT ); Fri, 11 Mar 2022 12:00:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350414AbiCKRAW (ORCPT ); Fri, 11 Mar 2022 12:00:22 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7045694B8; Fri, 11 Mar 2022 08:59:18 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3E63C61D85; Fri, 11 Mar 2022 16:59:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6251C340EE; Fri, 11 Mar 2022 16:59:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1647017957; bh=TfUoDniLNAUWpN5c0ZvcL19CsqAGIJipVHp+JX8IZYU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=IGNZyrBivI/tTqZCSj1SnNnLybgw7ILcz/GOPJIbv9s5TofQZKuRam1jdoh8quoAH RpfhJqKAOuD+BMhM98wO11QJaJCPGonkuOORU0/BvxI/Cm4Y/5+NLoASTIy1tIrCId 1UPuuHbLLcwa7If6D3lkZj0Dc4vjDL0GPjeZzh1zASE22jHf5EfN2pv0ViRm52ePDk hF/Tt9Ob0GO16bmDuA7zZAWSdjYkAdFOVMpzzHJStzsoIqYVP/obqTM+ArqCqytbpd HAIxODjbQgivDWVj8xIhAc7chRx3TxvHcKeIdo6vSpQ8l2FFUkl0+pICp1EZYxF0TP euJFwelKIZxmw== Received: by mail-yw1-f181.google.com with SMTP id 00721157ae682-2dc348dab52so100167267b3.6; Fri, 11 Mar 2022 08:59:17 -0800 (PST) X-Gm-Message-State: AOAM532Z4Mk9g0rl+RDeGxH38EjAA1flOcSiVIVwutt5yD1yF8lUS6Z2 xNIUNh4nc3qoUljz2rKooBBuS2oQZJkWfmxP7ko= X-Google-Smtp-Source: ABdhPJyjs53YNBDzki/gNd5IjlxDqN3gpH+kRPQ8Tg0rq78PB5ym7q5nPhRgFnuoO2cOP4YEesEHrF0VH/xjHrloqiw= X-Received: by 2002:a81:23ce:0:b0:2dc:b20:cc73 with SMTP id j197-20020a8123ce000000b002dc0b20cc73mr9213650ywj.130.1647017956691; Fri, 11 Mar 2022 08:59:16 -0800 (PST) MIME-Version: 1.0 References: <20220309064209.4169303-1-song@kernel.org> <9516f407-bb91-093b-739d-c32bda1b5d8d@kernel.dk> <38f7aaf5-2043-b4f4-1fa5-52a7c883772b@kernel.dk> <2b437948-ba2a-c59c-1059-e937ea8636bd@kernel.dk> <84310ba2-a413-22f4-1349-59a09f4851a1@kernel.dk> In-Reply-To: <84310ba2-a413-22f4-1349-59a09f4851a1@kernel.dk> From: Song Liu Date: Fri, 11 Mar 2022 08:59:05 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] block: check more requests for multiple_queues in blk_attempt_plug_merge To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-raid , stable@vger.kernel.org, Larkin Lowrey , Wilson Jonathan , Roger Heflin Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hi Jens, On Fri, Mar 11, 2022 at 6:16 AM Jens Axboe wrote: > > On 3/10/22 5:07 PM, Jens Axboe wrote: > > In any case, just doing larger reads would likely help quite a bit, but > > would still be nice to get to the bottom of why we're not seeing the > > level of merging we expect. > > Song, can you try this one? It'll do the dispatch in a somewhat saner > fashion, bundling identical queues. And we'll keep iterating the plug > list for a merge if we have multiple disks, until we've seen a queue > match and checked. This one works great! We are seeing 99% read request merge and 500kB+ average read size. The original patch in this thread only got 88% and 34kB for these two metrics. Thanks, Song [...]