ppc405ex + gigabit ethernet

[john.p.price at l-3com.com]

I have developed a board with the AMCC PPC405eX running at 600MHz and experimented with two transmission methods;

 

1.    Raw socket w/jumbo frames ¨C approx. 600Mbits/sec

2.    TCP using writev w/jumbo frames ¨C approx. 525Mbits/sec

 

From: linuxppc-dev-bounces+john.p.price=l-3com.com at lists.ozlabs.org [mailto:linuxppc-dev-bounces+john.p.price=l-3com.com at lists.ozlabs.org] On Behalf Of Lada Podivin
Sent: Wednesday, July 01, 2009 7:25 AM
To: LiuMing
Cc: linuxppc-dev at ozlabs.org
Subject: Re: ppc405ex + gigabit ethernet

 

Thank you for your reply!
Yes, I agree the CPU is the bottleneck. But I have performed more tests with the netperf tool and results seem strange to me. If I send 800 B of data, the resulting speed is aproximately 100 Kb/s. On the other hand, If I try to send 32KB chunk of data with jumbo frames turned on, resulting speed is about 600 Kb/s (300-400 without jumbo frames). My ppc405ex runs at 600 MHz.

So it seems that it is definetely better idea to call sendto() less frequently with bigger amounts of data, than to call it more often with smaler amounts. Is it because smaller data means more frequent user space/kernel space switching? Or is it network related issue?  

Thanks!

Best,
Lada

2009/7/1 LiuMing <eemingliu at hotmail.com>

Hi,
According to our experience on PPC405 + Gigabit Enet, your result is already very reasonable. For UDP transmission, it can be around 400 Kb/s because of the CPU bottleneck (in our case 300 MHz ppc405). If you want to further improve it, a faster CPU is needed to process the TCP/IP stack, or you may buy commercial TCP/IP stack rather than using the free Linux one. 
 
BR
Ming
 

________________________________

Date: Tue, 30 Jun 2009 15:58:53 +0200
Subject: ppc405ex + gigabit ethernet
From: lada.podivin at gmail.com
To: linuxppc-dev at ozlabs.org



Hi,

I benchmarked performance of my network, which contains ppc405EX (Kilauea board, kernel 2.6.30 from Denx) connected with a linux desktop via gigabit ethernet. I used the netperf tool: 

netperf -t UDP_STREAM -H 192.168.1.1 -- -m 32768

So I was sending UDP packets to the desktop. The resulting speed was about 370 Kb/s. I tried to send the packets to several different computers - with the same result. So the ppc board is the bottleneck in this case.

Is there any possibility to improve the gigabit capabilities of the ppc405EX? Is there anyone who achieved a better performance with ppc4xx boards?

Thanks!

Best,
Lada Podivin



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