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=-5.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 E5CCFC4363A for ; Tue, 20 Oct 2020 14:47:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 758A921534 for ; Tue, 20 Oct 2020 14:47:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="Frxve8Hj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408396AbgJTOrn (ORCPT ); Tue, 20 Oct 2020 10:47:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2408377AbgJTOrm (ORCPT ); Tue, 20 Oct 2020 10:47:42 -0400 Received: from mail-io1-xd43.google.com (mail-io1-xd43.google.com [IPv6:2607:f8b0:4864:20::d43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1605C061755 for ; Tue, 20 Oct 2020 07:47:41 -0700 (PDT) Received: by mail-io1-xd43.google.com with SMTP id h21so3691935iob.10 for ; Tue, 20 Oct 2020 07:47:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:subject:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=eTDTO76croA6fWZRrh4GlbI2rKBSNz7UAk22k08uTPM=; b=Frxve8HjbssplEMsSfSy/dOZpZIB1gr94ZuFWIrz5FDpLLApxH4IYkCnzdRKiy6NeO GpdZmUZHjCKV8RqvDqPJ7tAdKHHKKIUUT2FBXMlR7/qpOP4wK1WlpEYeeNYb0d+WSlZs syNDv0WdiYtc4ddqYt91wWPui2shlcOoiHoajdbFRqlp0XGHtHE6/JhklRmj4qWSZDoQ G71GBUHu8pU3hb24Pgoa/esQeqBlVl2kiK3/A2NRlO1GmIo/3PeTCAMG/9ryqfHxTRv4 PjmvG5MFBFrl3uHglfBlEwYXzluwTaIMXoVref53NIGVNi4VMbLjypPZv360ABQG6rfO libQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:subject:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=eTDTO76croA6fWZRrh4GlbI2rKBSNz7UAk22k08uTPM=; b=BwuZEa1hLCmz2Nufe8vjc0SAbpObwCUud7pyphWNrcmsf6avIEQ5FQe7PBzI+Lh00z /dUBZmtGdARkLARs3vaVgK4VsMMGCKxOmicBPXNjiJEgz4OnZcmSTonEseIeL6VzHz/u guBxMY2k2jiDRqVkk+VeQ8IeO19hizE5GKItO/O+oj54QYoLzalHOh3CUHRQP/UilH3z 71pap5T0esjenc7vrTwD/Hvzz5lR4Huse2hHxt2GxN8C+Zp0+bDG2iBueuXNvt2ECO0E ft/paeU32WMTzWrLCKXlG4sPu68fMpGGQrEw4GSm3DJKDcZIhWZ037PyhYuGM9cHTuNY idzA== X-Gm-Message-State: AOAM531VQkvjqW1w014wQh7YdasR2T+CrCliLh1fDHRnfQ509mZOdMe3 q3NgW+vywsEblDMady/mMV906w== X-Google-Smtp-Source: ABdhPJzugJUapJqFqhm/L0H5rAz1cZgRoq9Ez3koxFh5KEjr3YMJlow0oKYLaAF2dBQ/9Ji4kSSCBw== X-Received: by 2002:a6b:3c14:: with SMTP id k20mr2449719iob.12.1603205261027; Tue, 20 Oct 2020 07:47:41 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id r3sm1827026iog.55.2020.10.20.07.47.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 20 Oct 2020 07:47:40 -0700 (PDT) From: Jens Axboe Subject: Re: [PATCH 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig To: Kent Overstreet Cc: linux-kernel , fsdevel , Andrew Morton , Kent Overstreet , Matthew Wilcox References: <20201017201055.2216969-1-kent.overstreet@gmail.com> <20201017201055.2216969-3-kent.overstreet@gmail.com> Message-ID: <0da8d117-04ca-c236-dd3f-a6abbaf4097e@kernel.dk> Date: Tue, 20 Oct 2020 08:47:39 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201017201055.2216969-3-kent.overstreet@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 17, 2020 at 2:11 PM Kent Overstreet wrote: > > Convert generic_file_buffered_read() to get pages to read from in > batches, and then copy data to userspace from many pages at once - in > particular, we now don't touch any cachelines that might be contended > while we're in the loop to copy data to userspace. > > This is is a performance improvement on workloads that do buffered reads > with large blocksizes, and a very large performance improvement if that > file is also being accessed concurrently by different threads. > > On smaller reads (512 bytes), there's a very small performance > improvement (1%, within the margin of error). I ran this through my buffered testing, and no ill effects observed. It also provides a nice boost on the read side for a mixed read/write verification workload I have. Reviewed-by: Jens Axboe -- Jens Axboe