From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail2.tohojo.dk (mail2.tohojo.dk [77.235.48.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 2D0E421F359 for ; Thu, 23 Apr 2015 02:01:26 -0700 (PDT) X-Virus-Scanned: amavisd-new at mail2.tohojo.dk Sender: toke@toke.dk DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toke.dk; s=201310; t=1429779678; bh=AjZovK9ZRMrMAe8yQQsvg5Svx80LAizUkhk7MmkSsFc=; h=From:To:Cc:Subject:References:Date:In-Reply-To; b=HU38YN5LiN4BE4LxtZTEbqvv6eiB+S999c175grYWsnBwX8gJdhafmOCuh2uzGVyB aQKbXGDPyc3FSoLmwt3bbAkXZVe8bTG9z+92O3gh/RdE+GNiRWd+aRXfGsPu8gSwpB TSunCSvCJOVsyF87pCDZ2dovcCuFN3LvXDGbxd08= Received: by alrua-kau.kau.toke.dk (Postfix, from userid 1000) id 4BFFBC40255; Thu, 23 Apr 2015 11:01:17 +0200 (CEST) From: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= To: Adrian Popescu References: <5BC1CA30-289D-42B4-95CD-3AE5D7B96F09@gmail.com> Date: Thu, 23 Apr 2015 11:01:17 +0200 In-Reply-To: (Adrian Popescu's message of "Thu, 23 Apr 2015 00:02:35 +0300") X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87383r9q1u.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Cc: cake@lists.bufferbloat.net Subject: Re: [Cake] Cake3 - source code and some questions X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Apr 2015 09:01:56 -0000 Adrian Popescu writes: > Seeing worse latency under load (20-100 milliseconds) isn't uncommon. > I believe this to be a regression in the kernel or in the network > drivers. I don't see this behaviour at all: $ ls -l /sys/class/net/enp0s25/device/driver :( 0 lrwxrwxrwx 1 root root 0 Apr 21 16:05 /sys/class/net/enp0s25/device/driver -> ../../../bus/pci/drivers/e1000e/ $ ping 130.243.26.1 -c 100 # this is my default gateway ..snip... --- 130.243.26.1 ping statistics --- 100 packets transmitted, 100 received, 0% packet loss, time 99000ms rtt min/avg/max/mdev = 0.341/0.801/28.260/2.769 ms $ cat /proc/loadavg 9.29 8.43 5.30 14/508 6665 (yes, this is while running a cpu-hungry data processing application in the background on all eight cores) $ uname -a Linux alrua-kau 3.19.3-3-ARCH #1 SMP PREEMPT Wed Apr 8 14:10:00 CEST 2015 x86_64 GNU/Linux $ tc qdisc show dev enp0s25 qdisc pfifo_fast 0: root refcnt 2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 (hmm, why am I running pfifo_fast?) Repeating with sch_fq: $ ping 130.243.26.1 -c 100 ...snip... --- 130.243.26.1 ping statistics --- 100 packets transmitted, 100 received, 0% packet loss, time 98998ms rtt min/avg/max/mdev = 0.358/0.468/1.278/0.151 ms -Toke