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=-5.3 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,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 BD2F3C43462 for ; Fri, 7 May 2021 14:59:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CD706145E for ; Fri, 7 May 2021 14:59:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237732AbhEGPAV (ORCPT ); Fri, 7 May 2021 11:00:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237735AbhEGPAU (ORCPT ); Fri, 7 May 2021 11:00:20 -0400 Received: from mail-io1-xd2d.google.com (mail-io1-xd2d.google.com [IPv6:2607:f8b0:4864:20::d2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18624C0613ED for ; Fri, 7 May 2021 07:59:21 -0700 (PDT) Received: by mail-io1-xd2d.google.com with SMTP id z24so8222270ioi.3 for ; Fri, 07 May 2021 07:59:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=ZI0bcFPJ2tB9w0Gpmkj9hW2yBs41/ZZ7AdB8tXpcJ6E=; b=1sF8kkl0oiBEzdziAi6zItCMjm0zTh9wN2VDqE3XA+oy/ZFRwHwQ1SMnlhm8UYR1BY mUNZPoVTSP42VaTmvh+wrrQwB6gvCxUv85siGvP4/LbRpqZt7/iUq2Cj8Tng2qAJZmVj W2NCtStma6SAZFxxAP8SfxMgRU80Y3UjFtylrgL8C7MLlsnKCe2sreef0d9ovm10ggEj 7Lf1FnuAGpxXLidRqqWUxBj8iVGUcrvx5fw4Z/y5r31aSfizch7vQMN2q0bCWP9cnin3 Drxq/TZ0D6S+7y638G0hlRoaakWyORwVnCyQ7KSw5XMdWCEOWoymucVwdW9Hiebh3IY4 E6ow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=ZI0bcFPJ2tB9w0Gpmkj9hW2yBs41/ZZ7AdB8tXpcJ6E=; b=aUMa9US04eTIOsn05JLfj5VCTBulwUF37/QY8wS179M0a7PPiNhbxDhpdVi0uvdSuK ynHK0j/G0sE2mNm6oSDJT2rJoOjFSKrq2x3ZEb/bJ+EouRgv4be0r7BpPiC5dhYeajvZ Wc1WvUB4sQZ/CKtvALfVOeihbsBRTuyL6M0+LeL5TZz7pac4RBs6ABhcVvTmf5JwgldL KCQP5xFYW6ygsT2nOx2fLxfIYbBXquevkvRT5J9jfx4wt0mNpEE4oTFAcxTz+M5+6gda C8gzoYiu8Mw09Yet0yy8qgXTw3TEUVkviIzDNHH7Zagnvw+ZPQeuSrXYm//J0sIzqsFN 7QOA== X-Gm-Message-State: AOAM533WPV6HF2ZFesG7Qv/puqxzDyIXTj00xBnjyniQCLAk53xQFyiP bvUF2+4ADoW/3px6JNV6cKivgw== X-Google-Smtp-Source: ABdhPJxijx6e3v21+945OHqw2INCZe53gErjSGMh4PgWqDOnfDVdO5PyS6Vqvc1VA2KnWBEbkt753g== X-Received: by 2002:a6b:7901:: with SMTP id i1mr7999861iop.41.1620399560342; Fri, 07 May 2021 07:59:20 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id q3sm1595752ils.61.2021.05.07.07.59.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 07 May 2021 07:59:19 -0700 (PDT) Subject: Re: [PATCH] block: reexpand iov_iter after read/write To: Al Viro Cc: Pavel Begunkov , yangerkun , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, io-uring@vger.kernel.org References: <20210401071807.3328235-1-yangerkun@huawei.com> <7ff7d1b7-8b6d-a684-1740-6a62565f77b6@gmail.com> <3368729f-e61d-d4b6-f2ae-e17ebe59280e@gmail.com> <3d6904c0-9719-8569-2ae8-dd9694da046b@huawei.com> <05803db5-c6de-e115-3db2-476454b20668@gmail.com> <2ee68ca3-e466-24d4-3766-8c627d94d71e@kernel.dk> From: Jens Axboe Message-ID: <9c83335a-dbd4-dde7-ca6a-14ed5d7a6fc1@kernel.dk> Date: Fri, 7 May 2021 08:59:21 -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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 5/6/21 3:08 PM, Al Viro wrote: > On Thu, May 06, 2021 at 01:15:01PM -0600, Jens Axboe wrote: > >> Attached output of perf annotate for that last run. > > Heh... I wonder if keeping the value of iocb_flags(file) in > struct file itself would have a visible effect... A quick hack to get rid of the init_sync_kiocb() in new_sync_write() and just eliminate the ki_flags read in eventfd_write(), as the test case is blocking. That brings us closer to the ->write() method, down 7% vs the previous 10%: Executed in 468.23 millis fish external usr time 95.09 millis 114.00 micros 94.98 millis sys time 372.98 millis 76.00 micros 372.90 millis Executed in 468.97 millis fish external usr time 91.05 millis 89.00 micros 90.96 millis sys time 377.92 millis 69.00 micros 377.85 millis -- Jens Axboe