[Click] Userlevel performance issues

[Robert Ross]

Sorry, I wasn't clear that the queues are necessary for our
configuration.  The configuration is somewhat complex.  I was only
attempting to highlight the important parts.
 
Robert Ross
DSCI Inc.
Office: 732.542.3113 x173
Home: 609.702.8114
Cell: 609.509.5139
Fax: 253.550.6198
 

________________________________

From: Beyers Cronje [mailto:bcronje at gmail.com] 
Sent: Friday, January 25, 2008 7:31 PM
To: Robert Ross
Cc: click at pdos.csail.mit.edu
Subject: Re: [Click] Userlevel performance issues


Hi Robert,


 

	*       We first found that when UserLevel Click started pulling
from a
	PCAP file, the performance of the ToDevice() appeared to drop
sharply.
	What I mean by this is that the ToDevice() pull handler reported
values
	in the range of 200 packets/second once the PCAP file started
reading.
	This resulted in the outbound queue just prior to the ToDevice()
filling
	up and eventually overflowing because the packet rate in the
PCAP file
	is far more than 200 packets/second.


You dont have to use a queue between FromDump and ToDevice as FromDump
is an agnostic element. In other words you can connect Todevice directly
to FromDump which should ensure that at least no packets are dropped and
you should see best ToDevice performance.

Also there are a few tuning parameters. Try tuning your NIC TX Ring
size. On the e1000 driver the default TX ring size is 256, experiment
with different value to see if it makes a difference.ToDevice uses a
packet socket from transmit, so it might be worth experimenting with
/proc/sys/net/core/wmem_default
/proc/sys/net/core/wmem_max


Beyers