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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 D0294C49ED7 for ; Sat, 14 Sep 2019 00:31:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9805020830 for ; Sat, 14 Sep 2019 00:31:16 +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="K548ZTJE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389097AbfINAbP (ORCPT ); Fri, 13 Sep 2019 20:31:15 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:41573 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388296AbfINAbP (ORCPT ); Fri, 13 Sep 2019 20:31:15 -0400 Received: by mail-pg1-f195.google.com with SMTP id x15so16105493pgg.8 for ; Fri, 13 Sep 2019 17:31:15 -0700 (PDT) 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=GZS0eMO5E5zSRugyeXgeD/cE6Edijnu4rZNFSWVvyE8=; b=K548ZTJEQ6iFC5z3YdwevITK1iNbgK/vue1InwebFMKHAUjYrEnTWfspcXJ6hGnwaS EGC8rQNV84p6P01VsYPZfaJyg3QJvjbVyfpJCuZCeoCgnOPlnKOU9A6IHwvthZbYJeib A/gg6kOGvOCoKuo+Zrk3B4GaU0DeB2d0PBZK3UwB1hgYW2XlUf4U5uYM4W75bYpGZzdE s02D4+6c6XwU8bbIR0bINDp6B0JMKQFWqoYF57rKupI2gT4Co+PdQubLPAtXFzsdhKe4 jMB8/5Bjr24fZOn1D8eQ7VP0SvulhIki2bR1ugBynhWwx4nO9b0OoU6x5OOCoHX7pnWa ztJw== 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=GZS0eMO5E5zSRugyeXgeD/cE6Edijnu4rZNFSWVvyE8=; b=dTtWfAZwg2BDxeMJKmwrUZpQatQpeKG34boymcdnuFNZJnP7d6NAfNIEb2BBAcGqsh lsc3ahAx9bPgjFh3DTkgIUEtDkKuc+0evpgXPxx5PfHlXDx/K/OfE6Wy/6pL9KAPAjwH wZ0y4WJB2YMS6pLx4EgoORAornAzzT8oX4DPQ8DkgT/1XekP3AUm+Tiy3gnG0kG6S+wL 2KFTAaQBTm7xiHoWXdJFqpJKkOegiJ3oyX7CQ2NgD+YFFMgrNHQA9lBMbmdn1YQ/2wfl yhxz2VAYCk4jQXXCp2q6xddOqy1beBYliaJYn1qbbJT7CI628MDuc995jINA/MtrVo+7 C7WQ== X-Gm-Message-State: APjAAAWRD9/6AwL+lq4RXnvu93R9KDcjkPokuVtpnLfBt/JYmieEZnjs iMylqYSjnVMYO2cGm1bVX+nKcg== X-Google-Smtp-Source: APXvYqyBRXdUrqfuDtkgroCENQHx7jGh5ioqxn1eRQ/mEpAduszh5yTIrIY4U8/ZsJ3pp2gZczHbvA== X-Received: by 2002:a17:90a:be13:: with SMTP id a19mr189147pjs.55.1568421074785; Fri, 13 Sep 2019 17:31:14 -0700 (PDT) Received: from ?IPv6:2605:e000:100e:83a1:4d1e:aad2:f066:c964? ([2605:e000:100e:83a1:4d1e:aad2:f066:c964]) by smtp.gmail.com with ESMTPSA id m16sm2222389pgb.84.2019.09.13.17.31.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 Sep 2019 17:31:13 -0700 (PDT) Subject: Re: [RFC PATCH 0/2] Optimise io_uring completion waiting To: "Pavel Begunkov (Silence)" , Ingo Molnar , Peter Zijlstra , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: From: Jens Axboe Message-ID: Date: Fri, 13 Sep 2019 18:31:11 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 9/13/19 4:28 PM, Pavel Begunkov (Silence) wrote: > From: Pavel Begunkov > > There could be a lot of overhead within generic wait_event_*() used for > waiting for large number of completions. The patchset removes much of > it by using custom wait event (wait_threshold). > > Synthetic test showed ~40% performance boost. (see patch 2) Nifty, from an io_uring perspective, I like this a lot. The core changes needed to support it look fine as well. I'll await Peter/Ingo's comments on it. -- Jens Axboe