[ECOS] udp problem & network stack questions

Dan Conti danc@fullplaymedia.com
Tue Jun 11 17:20:00 GMT 2002


As far as the 'eth_recv out of MBUFS' error message, usually it's caused
by leaving a socket open. I.e. you have a socket that is receiving
incoming data, but you're not reading off it, so the data gets buffered
up. The easiest way to get around it is to increase the amount of memory
reserved for MBUFs (this is in the network settings in the config tool).
When i saw this last, i noticed that a single socket could use all the
available memory for MBUFs.

For item number 2, if you have a lot of network traffic you might see a
performance hit once your network is initialized. 50% is a bit much,
especially on a strongarm; i guess i'd be curious as to how much
broadcast/multicast traffic you are getting.

On item number 3 i would assume you are talking about the networking
stacks; i dont have much insight into either, sorry.

-----Original Message-----
From: aacquaviva@deis.unibo.it [mailto:aacquaviva@deis.unibo.it]
Sent: Tuesday, June 11, 2002 5:12 PM
To: ecos-discuss@sources.redhat.com
Subject: [ECOS] udp problem & network stack questions


Hi,
I have some question regarding tcp/ip.

1. I tried to set-up an udp client-server application between my
strongarm 
platform and the PC. The server downloads an mpeg compressed stream to
the 
client-decoder after a request message. When the server starts to
download, 
the client send me the "recv out of MBUFS" error message. What could be
the 
reason? How can I trace the work of network threads to debug this
problem?

2. Using a tcp/ip connection (that works) I noticed that the decoding
time 
of the mpeg3 decoder doubles if during the decoding the network threads
are 
active.
More clearly, the test I've done to understand why the mpeg3 decoder was
not 
real-time is the following:

- The client initializes the interfaces (init_all_network_interfaces)
- connects to the server
- starts decoding taking encoded frames from the memory

The decoding time in this case is double with respect to the secoding
time I 
get without the first two steps. Is it possible such a performance 
decreasing only caused by the presence of network threads?

3. What's the difference in using Free instead of OpenBSD?  Is there any

performance hints?   

Thanks a lot for your help,
Andrea Acquaviva.



-- 
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss


--
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss



More information about the Ecos-discuss mailing list