Dayton, Dean wrote: >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.
Just to be a complete ass a 66MHz MPC885 with two FECs operating as a virtual switch is able to keep two 100MBits ports fully saturated. So I think that the hardware can certainly handle it. Not under linux though. >>-----Original Message----- >>From: Adisorn Ermongkonchai [mailto:aermongk at yahoo.com] >>Sent: Sunday, June 06, 2004 2:01 PM >>Subject: Poor 8260 FCC Ethernet performance >> >>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. Regards Pantelis ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
