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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ADAAC433EF for ; Fri, 18 Mar 2022 15:02:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237255AbiCRPDm (ORCPT ); Fri, 18 Mar 2022 11:03:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237221AbiCRPDl (ORCPT ); Fri, 18 Mar 2022 11:03:41 -0400 Received: from mail-wm1-x32e.google.com (mail-wm1-x32e.google.com [IPv6:2a00:1450:4864:20::32e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFFC51D78BF for ; Fri, 18 Mar 2022 08:02:22 -0700 (PDT) Received: by mail-wm1-x32e.google.com with SMTP id r7so5004730wmq.2 for ; Fri, 18 Mar 2022 08:02:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :references:from:in-reply-to:content-transfer-encoding; bh=gGq/nKPdmtv2ZG0iPW1Xpo7Gmvkuu1Z1Jrcb2+k23Fo=; b=B130cqAk5s9UwNNKR/QAE2dca9T5nmT5LUAbPGozq7OcnCSwT00LzRWxUaV72xy+M3 Q2TSgOAhIDNvU3DkJ6zsvRS1SxkM3/TlnJlI62eWR7pkk6J7PiMDVzs213yYJ3YN5crd trcgTj771M7cAS7YjX+xJX1V3qBlmepVrZxFURw7bOX4L0fyY/GYcAkqm3mC7QRM06X5 bpZsofUBn2YtvKA8vEA1GP026pHQ/JQGrJ5/Znv31Ky/1KWcc0y31rgRsjmrrwWiG/PQ skcVWIiM7JfzTxK+OSb5+Sd7JjjqMz8L9v/Mq4VNbvrYvkqRjvPwhGPnZWN3a/EOqeri dlww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:references:from:in-reply-to :content-transfer-encoding; bh=gGq/nKPdmtv2ZG0iPW1Xpo7Gmvkuu1Z1Jrcb2+k23Fo=; b=Hs0z95U18V1aLD+uWpD8UqwFqxFCEdvEqI8xVg3NgHRJtqyexKPxewrlF6zdJ6LijR buXHcaiGvQAQ3Fo7RDil9vtHw/kyTDZxN03Mqfowtp8qXDiDImNyrnEClDHz3JiSeXL2 DizkSt9IRyxcSC5vQSGy8GZTXzx0pJ8TIOBOwqHCDwYsUn3/LDPSs6bE5xtucCLqopzJ ZQbY4u0I69FfNqMFrq6pVnjJKQiHiuI+QNjs+17ejTwV4Dp+4QqXaYGg/HNMSI/gbcLL inPz6ViQyPsaEcQgfLZdwNwsfL8R2INGgHpcFrP7wgjvhAq/3wcQilg3oPinknh+crrS ws7w== X-Gm-Message-State: AOAM532TkvK7LoMyMEejWV/01iAbbg75pJCBJxJN85S5fI6SKdTgDIfN M8fv3CSjy7T99KaDl2NbOoLuJekM7kjOkg== X-Google-Smtp-Source: ABdhPJzuw9IJxEkEOzCpaBFeAzwtE/FoSnK272hNktfbCOJSYjjbrGyqgEzjXR6y5XdRkCju0jP5Dg== X-Received: by 2002:a7b:c30a:0:b0:389:9e1e:a15f with SMTP id k10-20020a7bc30a000000b003899e1ea15fmr8356526wmj.28.1647615741347; Fri, 18 Mar 2022 08:02:21 -0700 (PDT) Received: from [192.168.8.198] ([85.255.234.70]) by smtp.gmail.com with ESMTPSA id t187-20020a1c46c4000000b0038c043567d3sm6951931wma.1.2022.03.18.08.02.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Mar 2022 08:02:21 -0700 (PDT) Message-ID: <458031c4-2eca-7a9e-ab9f-183a2497af48@gmail.com> Date: Fri, 18 Mar 2022 15:00:56 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.0 Subject: Re: [RFC 0/4] completion locking optimisation feature Content-Language: en-US To: Jens Axboe , io-uring@vger.kernel.org References: <016bd177-1621-c6c1-80a2-adfabe929d2f@gmail.com> <23c1e47b-45e5-242f-a563-d257a7de88ed@kernel.dk> From: Pavel Begunkov In-Reply-To: <23c1e47b-45e5-242f-a563-d257a7de88ed@kernel.dk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/18/22 14:52, Jens Axboe wrote: > On 3/18/22 8:42 AM, Pavel Begunkov wrote: >> On 3/18/22 13:52, Pavel Begunkov wrote: >>> A WIP feature optimising out CQEs posting spinlocking for some use cases. >>> For a more detailed description see 4/4. >>> >>> Quick benchmarking with fio/t/io_uring nops gives extra 4% to throughput for >>> QD=1, and ~+2.5% for QD=4. >> >> Non-io_uring overhead (syscalls + userspace) takes ~60% of all execution >> time, so the percentage should quite depend on the CPU and the kernel config. >> Likely to be more than 4% for a faster setup. >> >> fwiw, was also usingIORING_ENTER_REGISTERED_RING, if it's not yet included >> in the upstream version of the tool. > > But that seems to be exclusive of using PRIVATE_CQ? No, it's not. Let me ask to clarify the description and so, why do you think it is exclusive? >> Also, want to play after to see if we can also avoid taking uring_lock. > > That would certainly also be interesting! -- Pavel Begunkov