It's been awhile, but I seem to remember that some of the PPC drivers did not set up full duplex properly. Make sure that fcc_fpsmr is setting FCC_PSMR_FDE and FCC_PSMR_LPB properly. Also check to make sure that the phy is actually set up for full duplex.
Having said all that. There is a limit to how fast the processor can forward packets. This chip was designed to give a lot of flexibility in connectivity. It will not forward 100Mbps of small packets, especially not while running Linux. You could spend a lot of time and really optimize the data path and drivers for a very significant improvement in performance. But then you wouldn't have the flexibility of Linux. I run a 266MHz 8265 with Linux. With a very simple kernel configuration it can forward about 29000 pps (in on interface and out another). If I enable iptables,nat and a few other network options, the performance drops by about 50%. If I start configuring complex iptables rule, performance will continue to drop. Modifying the driver to NAPI would probably help. Dean Dayton > -----Original Message----- > From: Adisorn Ermongkonchai [mailto:aermongk at yahoo.com] > Sent: Sunday, June 06, 2004 2:01 PM > To: acurtis at onz.com > Cc: linuxppc-embedded at lists.linuxppc.org > Subject: Poor 8260 FCC Ethernet performance > > > > Hi Allen and Linuxppc-embedded guru, > > Referring to your 31 May 2002 post to LinuxPPC about > poor 8260 FCC Ether performance. Did you figure > out why is the FCC so slow? We have encountered this > problem as well. We use the newer MPC8270 with 400MHz > clock and 200MHz CPM speed with BCM5222 PHY. It > ended up running at only ~5Mbps on 100Mbps Ethernet > line. We just tried 1 FCC. > > Does anyone on this post see the same problem? We use > linux 2.4.18 with PPC pqii driver (somehow the other > driver didn't seem to work for all 3 FCC's) We > also tried on Motorola 8260 eval board and the result > is the same. We also tried MEN Micro F6, it gave > better result from 11MBps to 30Mbps. We also tried > just uboot to eliminate Linux out of the picture and > the result was about the same. > > I was about to give up on this MPC8270 then I saw this > post so I thought I try. I cannot believe that > Motorola would make a chip that support 3 FCC's > but can only run at this ridiculous speed. I am > software engineer, this could be hardware. > > Can anyone help me on this? I'm about to have to > change the processor to PowerPC 4xx. > > Thanks in advance. > > Regards, > Adisorn Ermongkonchai > > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
