From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx2.suse.de", Issuer "CAcert Class 3 Root" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 3089121F194 for ; Mon, 26 Nov 2012 07:10:29 -0800 (PST) Received: from relay1.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id 01BADA39D0; Mon, 26 Nov 2012 16:10:26 +0100 (CET) From: Oliver Neukum To: Dave Taht Date: Mon, 26 Nov 2012 16:10:43 +0100 Message-ID: <6215800.d6FWbLqba3@linux-lqwf.site> Organization: SUSE User-Agent: KMail/4.8.4 (Linux/3.7.0-rc6-12-desktop+; KDE/4.9.1; x86_64; ; ) In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Mailman-Approved-At: Mon, 26 Nov 2012 07:25:58 -0800 Cc: cerowrt-devel@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] debloating the Pi, maybe not. X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Nov 2012 15:10:29 -0000 On Friday 23 November 2012 17:43:24 Dave Taht wrote: > I was donated a raspberry pi in cambridge and got it booted today. > It's a very cool > box, an arm6, running debian, with hard floating point, and getting a complete > development environment running, getting it to do mesh networking, > graphics, apache, etc, on a 16GB SD card, was a breeze. > > But as for network performance: > > It only comes up at 100Mbit, and as noted elsewhere the ethernet chip > is hooked up over USB. > > dmesg > > [3.078644] smsc95xx 1-1.1:1.0: eth0: register 'smsc95xx' at > usb-bcm2708_usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:18:fc:ac > > The best the 3.2 kernel based networking can do is about 75Mbit/sec. > This eats 68% of cpu in the "system" (sy in top) and 30% in si (system > interrupt) Wow. What did you do to saturate the system like this? Blow empty UDP packages into the net? > I had had some hope of this being a good box to put some test tools on, > but with performance like this, I am back to leveraging the mips stuff. > > That said, I do intend to poke at the driver and update to 3.6 when > I get a chance, since we have patches lying around for both this > chip and the usbnet code. Nothing for performance in the mean time. Note that we don't try to do interrupt mitigation in usbnet. Regards Oliver