From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-x236.google.com (mail-qg0-x236.google.com [IPv6:2607:f8b0:400d:c04::236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 6DF9C3B25D; Sun, 1 May 2016 13:59:55 -0400 (EDT) Received: by mail-qg0-x236.google.com with SMTP id f74so61449478qge.2; Sun, 01 May 2016 10:59:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:subject:from:to:cc:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=6E2wKXyhlv5MaqgpR+5yAN3gExTS01ODe7dE4W6EvBQ=; b=rFba6k/mlFVyLFFaH1qM073cY+ftsNOLX3liWBj36SZwoVDGXzu+vqvSPuOYmR1G+D IDVg9DJ6XaQ4d44pjKgpHkChNmVMl9CyygCnp4AmB7AscX311TPXgEqr6Q5VoUk//Znv d5T0N+DTRDEjH2iBsHhK+IMOSQMS2NhG/RJ2Pn6GTsTV7BRVHASSTL9QG7+XKJb/kZWi sr3nbye/NaY4cGwYDGiu9gRG2061xrwFC1Jrq60XqrlCWSSbiKcbweoLmBWhgSfPU1mD VS+/jWCcUqcyyy1tyzUIj2FhNOXue13rbjf0Mjf0pwpy45r0kTuNXDLn7JujDl0gFlzW um4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=6E2wKXyhlv5MaqgpR+5yAN3gExTS01ODe7dE4W6EvBQ=; b=m0gmPHicNo4GzKMPSvq1QdV3wb5kt589wJP9EzReFhHGCOv1ZWkpXEEMt+/juC5xVt unayrEN3I3tIL7U8m9S1NFfjaoaOm6UUliABFx/k49JvuO6bfHtkqmLmV5xueAp0+izP aLQk3rkmS9h2l1CwzDS0g9rVbMjQVED7kAdkTGdc1vpIAsWjegUkjrSTbv5Krsb5q5ek zqQSAsOPEpCnV7PvwEUApifxGcEkRaO3PE90BszI4WeDtK9Gpb4tWDaWssStx61ffVYd SBH66GgMlX/CACTkosqKAquDrrh51/h9s/RR+Z7ICBlSV7DXeEjJ8i0biX+WV6sTiT2H dCCA== X-Gm-Message-State: AOPr4FV6dqNOkBNnQRG45/kryHFBHGptYyKDBml+J+2ks6T9D3X+L+xyY3zLPwLu59p2UA== X-Received: by 10.141.47.66 with SMTP id y63mr30010769qhe.74.1462125594978; Sun, 01 May 2016 10:59:54 -0700 (PDT) Received: from [100.96.106.16] ([100.96.106.16]) by smtp.googlemail.com with ESMTPSA id b6sm7940347qkh.12.2016.05.01.10.59.53 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 01 May 2016 10:59:54 -0700 (PDT) Message-ID: <1462125592.5535.194.camel@edumazet-glaptop3.roam.corp.google.com> From: Eric Dumazet To: Dave Taht Cc: ath10k , "codel@lists.bufferbloat.net" , make-wifi-fast@lists.bufferbloat.net Date: Sun, 01 May 2016 10:59:52 -0700 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Mon, 02 May 2016 15:49:25 -0400 Subject: Re: [Make-wifi-fast] [Codel] fq_codel_drop vs a udp flood X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 01 May 2016 17:59:55 -0000 On Sat, 2016-04-30 at 20:41 -0700, Dave Taht wrote: > >>> > >>> 45.78% [kernel] [k] fq_codel_drop > >>> 3.05% [kernel] [k] ag71xx_poll > >>> 2.18% [kernel] [k] skb_release_data > >>> 2.01% [kernel] [k] r4k_dma_cache_inv > > The udp flood behavior is not "weird". The test is wrong. It is so filling > the local queue as to dramatically exceed the bandwidth on the link. Well, just _kill_ the offender, instead of trying to be gentle. fq_codel_drop() could drop _all_ packets of the fat flow, instead of a single one. It is too cpu intensive to be kind to the elephant, since under pressure fq_codel_drop() needs to be called for every enqueue. Really, we should not try to let inelastic flows hurt us. I can provide a patch.