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 C8B0AC433FE for ; Wed, 16 Nov 2022 18:47:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231437AbiKPSrq (ORCPT ); Wed, 16 Nov 2022 13:47:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239413AbiKPSp0 (ORCPT ); Wed, 16 Nov 2022 13:45:26 -0500 Received: from mail-il1-x12e.google.com (mail-il1-x12e.google.com [IPv6:2607:f8b0:4864:20::12e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6128C63CEE for ; Wed, 16 Nov 2022 10:44:40 -0800 (PST) Received: by mail-il1-x12e.google.com with SMTP id d3so9633184ils.1 for ; Wed, 16 Nov 2022 10:44:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=6F8zpl58bT40JxRCaS05R51J3S3Cm7X4seeHIywQrFs=; b=G9FKTdHFM94LwDnKYS5xKSiYSZ6Klgc/e1X6czIeXi5ADydt5VC/Y1i2CqukKXDfMb TH3fbCu+CCV23jZ9OK2fqDMNizopoWMrYxHNFNZ+edTwowYKC/dYlayMgo88Wk2FGaxr EqLeEBDTXmCcmhynbLny9WYtNbkDuwXO6u7NGpA2Ees/gL6kN3tDL9lKgYsxtGJFvy0l z00kW0T6KTjqJuneg9b4XnnytM2/n2ZDkR5EpLLgCDDk74yrP0H46qXf+nRlave0ZWt4 Thm42e6bZ94Vvs3hInMkSGz3kifigkK4I3u72SsSLl826SN20nuqQen+30PVovdrW+58 58jg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=6F8zpl58bT40JxRCaS05R51J3S3Cm7X4seeHIywQrFs=; b=YTHKSXGehQiKPXI5ueEp/PoH6bmiHaK1jhvYhoyWgun8c7u1BQj07wIVGbXFypDxJN 74f4m+S5y4ee/Aem+eWLT0CRlJHDI6P1fGMPGcpCKKWt2xOOwpFHfuUQJ85FyUFapxtR AJpuEJlLoFoX4HsbEcMZi0vXE7biqU2+p9i4lZg4RghtIJObq4cz6EwFdM7qeG+6CF7a dC2nnMDZjO3dz8nAsg9PolelL7pgSkcqcN5c7KbdLZQqE12aZaC2wWcL1bGdAoXMFsFp NREj+U9jJI4q1XWVdvT6To+QPeijViJ8QTQYFwr5S6oLTHdonXvCAGWqAXkE8tZzgsO8 4GqA== X-Gm-Message-State: ANoB5pnRyz7I6qmQhnbvMoxsrPoKDgIXw+zlrl/iswi7Qwra3JUvJnyV URcXM7LvjUMhSLcRFZeZ+ymR3oV7EAk1Ow== X-Google-Smtp-Source: AA0mqf4H4NmH2GeAZ2fHObtyxSifcKL7+oq1AN7ckxhbHwnflINse6H77JNTx6Q+ynnTnWwP4tyBnw== X-Received: by 2002:a92:db49:0:b0:300:f59b:6d0c with SMTP id w9-20020a92db49000000b00300f59b6d0cmr11478732ilq.107.1668624279689; Wed, 16 Nov 2022 10:44:39 -0800 (PST) Received: from [192.168.1.94] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id p1-20020a92d481000000b002f9f001de24sm6513788ilg.21.2022.11.16.10.44.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 16 Nov 2022 10:44:39 -0800 (PST) Message-ID: <44c2f431-6fd0-13c7-7b53-59237e24380a@kernel.dk> Date: Wed, 16 Nov 2022 11:44:38 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [RFC PATCH v3 0/3] io_uring: add napi busy polling support Content-Language: en-US To: Jakub Kicinski , Stefan Roesch Cc: kernel-team@fb.com, olivier@trillion01.com, netdev@vger.kernel.org, io-uring@vger.kernel.org References: <20221115070900.1788837-1-shr@devkernel.io> <20221116103117.6b82e982@kernel.org> From: Jens Axboe In-Reply-To: <20221116103117.6b82e982@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 11/16/22 11:31 AM, Jakub Kicinski wrote: > On Mon, 14 Nov 2022 23:08:57 -0800 Stefan Roesch wrote: >> This adds the napi busy polling support in io_uring.c. It adds a new >> napi_list to the io_ring_ctx structure. This list contains the list of >> napi_id's that are currently enabled for busy polling. This list is >> used to determine which napi id's enabled busy polling. >> >> To set the new napi busy poll timeout, a new io-uring api has been >> added. It sets the napi busy poll timeout for the corresponding ring. >> >> There is also a corresponding liburing patch series, which enables this >> feature. The name of the series is "liburing: add add api for napi busy >> poll timeout". It also contains two programs to test the this. >> >> Testing has shown that the round-trip times are reduced to 38us from >> 55us by enabling napi busy polling with a busy poll timeout of 100us. > > Acked-by: Jakub Kicinski > > Thanks! Thanks Jakub! Question on the need for patch 3, which I think came about because of comments from you. Can you expand on why we need both an enable and timeout setting? Are there cases where timeout == 0 and enabled == true make sense? -- Jens Axboe