RE: High processing power and gigabit interface
From: emre kara <hidden>
Date: 2005-02-28 13:16:28
Hi everyone; Thank you all for your valueable answers. For summarizing the solutions, to overcome the problem about getting high troughput on ethernet devices: 1- Use NAPI version of ethernet drivers(I didnt hear its implemented for 440gx) 2- Change the processor with an much powerful one(like 8540, and I think there was also a NAPI driver for this processor, so it can also cover the first solution) 3- Use network processor The third solution is an expensive one,my project is not at that huge, so I eliminate this. And my question, I have good hardware and mid level linux device driver knowledge, but I never wrote an ethernet driver. Is there a lot of work for 440gx NAPI driver,can I write it easly,if so where can I start,(or did someone make it before?) or must I throw 440gx eval board to waste basket and buy a new platform? Thank you all.. Emre
--- "Howell, Kyle" <Kyle.Howell@barco.com> wrote: Hi Emre, I am not familiar with the Linux network driver for the 440, but the first thing I would check is that your network driver is using the new NAPI. With packets as small as 64 bytes, this kind of interrupt traffic would floor any processor without some form of coalescing. I am currently achieving ~800Mbits/sec throughput on a Motorola MPC8540 @800MHz (very comparable to the 440, AFAIK). That project involves passing data from a non-network interface onto the network and vice-versa. Achieving that speed required using the NAPI version of the net driver and using 4KB packets (Jumbo packets). I don't know how great the hit would be if that was network-network traffic or if we were doing anything more complex than simple data routing. I suspect that unless your encryption is hardware accelerated, you won't have a chance with anything less than a full multi-GHz processor. The other tasks could probably manage your required 200Mb/s on the 440 with enough tuning, though I'm not confident that would be true with packets as small as 64Bytes. Regards, Kyle Howell Engineer, BarcoView LLC kyle.howell@barco.com -----Original Message----- From: linuxppc-embedded-bounces@ozlabs.org [mailto:linuxppc-embedded-bounces@ozlabs.org]On Behalf Of emre kara Sent: Thursday, February 17, 2005 9:11 AM To: linuxppc-embedded@ozlabs.org Subject: High processing power and gigabit interface Dear All, I'am not sure if this kind of question can be asked on this mail-list, if not, sorry about it. In my project, we need high processing power on gigabit network interfaces. our system will achive routing,nat, encryption at minimum 200 Mbits bandwith. Firstly we decide to use amcc 440gx(ocotea)(because of TAH,2 gigabit interfaces etc..) and I had loaded linux kernel 2.6.10 and also denx's 2.4 kernel for our board..(with our (linux community) valueable helps..thanks alot..) I have tested 440gx routing performance with this two kernels, for doing this, we had send 64 bytes packets between two computer,but we could'nt see much more then 40Mbits routing performance on this tests. I think the problem with hardware, we have reached the limits. I need your suggestions,which processor is suitable for our app or where am I wrong. Thanks alot for the answers. Emre
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