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=-10.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 4164FC56201 for ; Thu, 19 Nov 2020 17:20:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D275A2468B for ; Thu, 19 Nov 2020 17:20:26 +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="VGMYR7GI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728896AbgKSRUF (ORCPT ); Thu, 19 Nov 2020 12:20:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727677AbgKSRUF (ORCPT ); Thu, 19 Nov 2020 12:20:05 -0500 Received: from mail-il1-x141.google.com (mail-il1-x141.google.com [IPv6:2607:f8b0:4864:20::141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F03CFC0613CF for ; Thu, 19 Nov 2020 09:20:03 -0800 (PST) Received: by mail-il1-x141.google.com with SMTP id z14so6009580ilp.11 for ; Thu, 19 Nov 2020 09:20:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=Cuh0RTTSFAlmIPVhGB92scgG2gp7uIXGl6U8eaIkwws=; b=VGMYR7GIyigGqFMlURJN1OniF74reh1UdQXfBzrlKlnYeM+WRXlnHYCvAek+XLZl+j fnMW4SKO1FBIJPHj2Yi6SohZxhvFabSdCp+cz9YCH2FNIeSNV62dzclA+evfaJH2QBOs Or3W4G6dSf6MJ1czMoPcLasp5lrGvUJu9RH+cPxkDlBy4F/tLGo6R8vg1bhpk8h1xlPH IvcvRDOyW/1XkjXvhwz6Jdg17E9LYTylvdyqaf7yXdmNocIbZLtvoDsXU01T+/2RfZkY 6xDKT6SF2aNEgX7rlD69MPQQakerXRxeaE3nPaaZ/WCkz12FdpPJxXHzisFXq1ATjZy+ LFOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Cuh0RTTSFAlmIPVhGB92scgG2gp7uIXGl6U8eaIkwws=; b=rjT3NOdXq5sZRff9Z1yjeuRg5pewAxUreeWg+VVD3Q+7wpgwAtr0QQBl86lSrVFBY1 iMjQzvVWFbE3t2UvuYqJK1mRLYK9qfXYFCHIgsIfuaSYiyC1ms4Nv75m8fS/2p9V2Jy1 4PsrqkdwqSFdNLW05rEix2AwnNPRU0K9k//oMhFKGH69BHNIJfEdhdi1qeOpQbtlZHIO b2Mf5O3n1C6H3sLvCJx+mmh/sI1lkcXxGHioNJX1iUkbxjUVF1p+FEUftZQcG5nmRthw 2+GO/GT/lDiPM2QN00L6Jm4I776jKRPfkBhNQBAG66LFeJhfw5cTmLIwUYJWQ+rFbXzM lzUg== X-Gm-Message-State: AOAM533VrDCKkR4LObXNgqOnHJoKnEyaY9SSpsVm6f7iPLsFSGH2AW3k I3GzkGtnsA+vy7bcIVrmbwGrjg== X-Google-Smtp-Source: ABdhPJxqW+pxzeKvGrbOkUbneyIPxMDLzPVQq32823a3f0cted9sUHxsKt6LdBhk+atDCT70aCQa4g== X-Received: by 2002:a92:d143:: with SMTP id t3mr2340629ilg.35.1605806403250; Thu, 19 Nov 2020 09:20:03 -0800 (PST) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id x5sm237863ilc.15.2020.11.19.09.20.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 19 Nov 2020 09:20:02 -0800 (PST) Subject: Re: [PATCH 0/2] optimise iov_iter To: Pavel Begunkov , linux-block@vger.kernel.org, Alexander Viro , linux-kernel@vger.kernel.org References: <2b50322d-821f-469e-6f57-072b54e25ef4@kernel.dk> <629cabf2-3a23-9d95-dd88-281ef4d49ddd@gmail.com> From: Jens Axboe Message-ID: <72a1df1a-810b-5bf1-39bd-b702188a875b@kernel.dk> Date: Thu, 19 Nov 2020 10:20:02 -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: <629cabf2-3a23-9d95-dd88-281ef4d49ddd@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-block@vger.kernel.org On 11/19/20 10:14 AM, Pavel Begunkov wrote: > On 19/11/2020 16:46, Jens Axboe wrote: >> On 11/19/20 8:29 AM, Pavel Begunkov wrote: >>> The first patch optimises iov_iter_npages() for the bvec case, and the >>> second helps code generation to kill unreachable code. >>> >>> Pavel Begunkov (2): >>> iov_iter: optimise iov_iter_npages for bvec >>> iov_iter: optimise iter type checking >>> >>> include/linux/uio.h | 10 +++++----- >>> lib/iov_iter.c | 10 +++++----- >>> 2 files changed, 10 insertions(+), 10 deletions(-) >> >> Nice! Tested this and confirmed both the better code generation, >> and reduction in overhead in iov_iter_npages(). > > Thanks! Did you find t-put/etc. boost with your setup? Yeah, for this kind of test, if we shave 1% off the stack overhead, that directly yields an increase in peak IOPS. My numbers were close to yours, dropped about 1% of system overhead. -- Jens Axboe