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 87EB3C433FE for ; Thu, 3 Dec 2020 17:51:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 30443207B3 for ; Thu, 3 Dec 2020 17:51:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731325AbgLCRuy (ORCPT ); Thu, 3 Dec 2020 12:50:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731136AbgLCRux (ORCPT ); Thu, 3 Dec 2020 12:50:53 -0500 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E67EC061A51 for ; Thu, 3 Dec 2020 09:50:07 -0800 (PST) Received: by mail-pj1-x1029.google.com with SMTP id b12so1556093pjl.0 for ; Thu, 03 Dec 2020 09:50:07 -0800 (PST) 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=ppnO25OuYQ/1IjELB2kgBioJi4rv6POx6IlxQIXXNpk=; b=HOHj6ayscVe3ZO0DpYfNEMtrxcPpXBfSBduTRP26eJAi9qWeDaEaqvnlWyD1tkgsNn WHf/c+iph12AtDq5ZPiB0xBf7vpVwaQ+d4FmzkhPANMYu7p/pjev/8GYudVFNTVY2ars R0psmS9bdHBmvimevhcc3vnoNApM2yiWbbZqFciw03VA6B2hsct4V9O85JtoFFYiWG/+ CQ1HnSZiPPrui+eqkQEZ//rCuCzBXtD68Sm5lSes2CW89A6EAEjmGkSAk95oQI7exFis skTuSOtL2uFNQ/9INU1C2swi0XB4WpYbH2P6PwK4LjQvHJAXEczMh6WIpsHUAxlFLy2R hq0Q== 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=ppnO25OuYQ/1IjELB2kgBioJi4rv6POx6IlxQIXXNpk=; b=r6bAlHTXveIPlupP00dceedBYzM6n6WRA8Jg8mMoFQbo68QHZJQE/jNwh/tjUQ57DD 3YjA525EvylBNqOCNoz7cNjST1s70qg8OnFnN20K7SWjjOuz928vp+8ND5tEjaTjxn3x kLSkpZH811LlOc9UW5we7woZtGajEwUG2TCLJCr8ZQNik9NVbA82hTX041kMEyVu/2Dt H0YX1bf+/aA1vOWazJb/XTnjPL1cR5hU3xr3yaigt9nUZ1GTeonfaMjuQyQITYNyVyxa +zflYFfhqVWwWGA4LWDx7i8yuetMHKGO26BvB/TU3+X55MvyHm53bXgRf+9q4lJ5oHQT afBw== X-Gm-Message-State: AOAM532AVkYjlMnqDBMnMJWRFdi1/7kw5LfgdmqMvAeIvLtL80gQpppy Uc/GNHJ4OIlvqqfjGebGT29MCZmqGgXQ8g== X-Google-Smtp-Source: ABdhPJxllA5bbSYrFdTd4toUUA9bg5VaxzP3LGpwUAiBmd2AiI89u7amTYs88FKICVUaW8O+Hlmcgw== X-Received: by 2002:a17:90a:7e0f:: with SMTP id i15mr230116pjl.93.1607017806270; Thu, 03 Dec 2020 09:50:06 -0800 (PST) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id e66sm2251101pfe.165.2020.12.03.09.50.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 03 Dec 2020 09:50:05 -0800 (PST) Subject: Re: [iov_iter] 9bd0e337c6: will-it-scale.per_process_ops -4.8% regression To: Linus Torvalds , kernel test robot Cc: David Howells , lkp@lists.01.org, kernel test robot , "Huang, Ying" , Feng Tang , zhengjun.xing@intel.com, Pavel Begunkov , Matthew Wilcox , Alexander Viro , linux-fsdevel , linux-block , Linux Kernel Mailing List References: <160596801020.154728.15935034745159191564.stgit@warthog.procyon.org.uk> <20201203064536.GE27350@xsang-OptiPlex-9020> From: Jens Axboe Message-ID: <8124ce0d-c934-0771-5e34-cf5ea030fc08@kernel.dk> Date: Thu, 3 Dec 2020 10:50:03 -0700 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-kernel@vger.kernel.org On 12/3/20 10:47 AM, Linus Torvalds wrote: > On Wed, Dec 2, 2020 at 10:31 PM kernel test robot wrote: >> >> FYI, we noticed a -4.8% regression of will-it-scale.per_process_ops due to commit: > > Ok, I guess that's bigger than expected, but the profile data does > show how bad the indirect branches are. It's also in the same range (3-6%) as the microbenchmarks I ran and posted. So at least there's correlation there too. -- Jens Axboe