From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-fx0-f42.google.com (mail-fx0-f42.google.com [209.85.161.42]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 797FBB700B for ; Wed, 8 Jun 2011 20:51:08 +1000 (EST) Received: by fxm1 with SMTP id 1so288510fxm.15 for ; Wed, 08 Jun 2011 03:51:03 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110607142213.2851f92e@schlenkerla.am.freescale.net> References: <20110607142213.2851f92e@schlenkerla.am.freescale.net> Date: Wed, 8 Jun 2011 16:21:03 +0530 Message-ID: Subject: Re: [gianfar]bandwidth management problem on mpc8313 based board From: Vijay Nikam To: Scott Wood Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello Scott, Thanks for the prompt reply. > What's your CPU utilization? The CPU may just not be able to keep up wit= h > that much traffic, with the software you're running. The software I am using to check bandwidth is 'iperf'. Without running iper= f the CPU utilization varies around 30-50% and with iperf running it shoots upto 99.9%. > What packet size are you using? The packet size is - 1518 + VLAN_Tag (4Bytes) =3D 1522 Bytes Another point which I would like to clear is that mpc8313 has eth0 (eTsec1)= of 1Gbps, if more than 50% of CPU Time is available then why the total bandwid= th should limit to less than 100 Mbps? At least 400Mbps should be expected, p= lease correct if I am wrong! Please acknowledge, thanks. Kind Regards, Vijay Nikam On Wed, Jun 8, 2011 at 12:52 AM, Scott Wood wrote= : > On Tue, 7 Jun 2011 18:32:37 +0530 > Vijay Nikam wrote: > >> Dear All, >> >> I have mpc8313 powerpc based board with silicon revision 2.1. the >> processor has two ETH ports (eTsec1 and eTsec2) i.e. eth0 and eth1. >> eth0 is 1Gbps port and eth1 is 100Mbps port. On board there is L2 >> switch from TANTOS2G (psb6972) supports one port 1Gbps, >> and from switch there are 4 more eth ports derived which are 100Mbps >> ports and port based VLAN is configured for this purpose. >> >> The interface between switch and eth0 (port of processor) is RGMII. So >> the processor port and switch port are connected on 1Gbps Link. >> The other 4 derived ports (100Mbps) are used to connect to external worl= d. >> On this board Embedded Linux is running of kernel version 2.6.23 with HR= T patch. > > That's rather old. > >> The ethernet controller driver in use is "gianfar" version 1.3 >> The driver is configured properly as it determines both links 1000Mbps >> (eth0) and 100Mbps (eth1) also verified with ethtool. >> >> After this I started to perform bandwidth test using iperf tool. >> When I performed this test on one port out of 4 derived ports I am >> getting bandwidth in the range of 80-85Mbps >> but when the same test is performed on 2 ports simultaneously then the >> per port bandwidth is reduced to 40-45Mbps. >> >> But my understanding is all of the 4 ports should support 100Mbps >> bandwidth simultaneously (as base port is 1Gbps). >> Then why bandwidth gets reduced when more than one port are >> communicating simultaneously? >> Any reason or suggestion I should check for this problem? > > What's your CPU utilization? =A0The CPU may just not be able to keep up w= ith > that much traffic, with the software you're running. > > What packet size are you using? > > -Scott > >