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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 3D727C433DF for ; Thu, 9 Jul 2020 00:08:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EE46206F6 for ; Thu, 9 Jul 2020 00:08:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="djbzOkJi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726107AbgGIAIQ (ORCPT ); Wed, 8 Jul 2020 20:08:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725848AbgGIAIP (ORCPT ); Wed, 8 Jul 2020 20:08:15 -0400 Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DF2CC061A0B for ; Wed, 8 Jul 2020 17:08:15 -0700 (PDT) Received: by mail-pf1-x443.google.com with SMTP id j20so200357pfe.5 for ; Wed, 08 Jul 2020 17:08:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=j1T68WPU1Q0aeLtsir+g+TaJRzzJbPMsVNVzePh8sxs=; b=djbzOkJisYcgxf1Dewj4sRK9BG/FnwqG0ELxCWXoVhAsHgh3bci1z3/8R5mwf30uUq YO9avQMAqrL2Gjju73prnId065F8HEWJWsrOaJYHOSfqcKU1Y1ltrmLRbsLn5GHC4sa+ lcK2WfAIFxQowRmR61pLLM/Ltf8+BMpK2j0D63aGWVQss+IsMkVTDfIX88BbxDEXTANe yFM8N8wJEjE03tEM7aFZ4vzvZGkxj/ZVDpPmVHCmCF2UeZ+V/DhWV1f6Zeufi8TzyLYi DQPqhqEX71cJswtG5ETJQ7ZU4E3SeTscMNpVOk/SeE7ftycEBYYnPsC2aAthvyHY86Ll vMDg== 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=j1T68WPU1Q0aeLtsir+g+TaJRzzJbPMsVNVzePh8sxs=; b=Kde+jFVJR6UZEw5lxd/9IW0/7sn1yYP6erPLq9MDEmt9jXP28/Ty01H+foIuLRR6NK y1vz9I4UlpW5gqTF2H6K+oGt5jEXnsvLbEK3pbZumUbZEFPO4ZZ45LDdjuOK6b6LBIxA LsxmIHXPUurKPypqpdTjxkS1C9nk2AL/xilZ1f9OU5eu+ayCjFPg6BWE+otPkIUotH0s xuK+UEeZBJt7M4jJCGW8CAv3JQiCS1p7V2ZbPBquXdLubQy2l4H6vJgjJxpPhmBmLz6t ZAvU6BDQoOvChIlfjP173wfYzF1/SXjUYeZnkBeX6xGqp+F9N90ZO12TaX6Nxi8mPQHY Y/CQ== X-Gm-Message-State: AOAM533kbYuAA1awzL86gvD6MERkxc+ciwuumOroKXwvAoQw6OScYNbf 5JLbLZXR9NiuvBZgJTV3amqjjzgY X-Google-Smtp-Source: ABdhPJxcoXtUJ9LFKHoQGilEkgQyKNxkfvTuK2SJzaQNRpYi//HFei2BRWoKUuMRODJGAAjLLWVC4g== X-Received: by 2002:a65:408b:: with SMTP id t11mr50844334pgp.407.1594253294743; Wed, 08 Jul 2020 17:08:14 -0700 (PDT) Received: from [192.168.86.235] (c-73-241-150-58.hsd1.ca.comcast.net. [73.241.150.58]) by smtp.gmail.com with ESMTPSA id p10sm546746pjp.52.2020.07.08.17.08.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Jul 2020 17:08:14 -0700 (PDT) Subject: Re: [PATCH net-next v2 2/2] net: sched: Lockless Token Bucket (LTB) qdisc To: "YU, Xiangning" , Eric Dumazet , Linux Kernel Network Developers References: <4835f4cb-eee0-81e7-d935-5ad85767802c@alibaba-inc.com> <554197ce-cef1-0e75-06d7-56dbef7c13cc@gmail.com> From: Eric Dumazet Message-ID: <91fc642f-6447-4863-a182-388591cc1cc0@gmail.com> Date: Wed, 8 Jul 2020 17:08:12 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 7/8/20 4:59 PM, YU, Xiangning wrote: > > Yes, we are touching a cache line here to make sure aggregation tasklet is scheduled immediately. In most cases it is a call to test_and_set_bit(). test_and_set_bit() is dirtying the cache line even if the bit is already set. > > We might be able to do some inline processing without tasklet here, still we need to make sure the aggregation won't run simultaneously on multiple CPUs. I am actually surprised you can reach 8 Mpps with so many cache line bouncing around. If you replace the ltb qdisc with standard mq+pfifo_fast, what kind of throughput do you get ?