[Xen-devel] httpd persormance in Xen environment.

[nayden <nayden@xxxxxxxxx>]

Hi, 

I am stresstesting httpd (Apache 1.3.31) under native linux and
xenolinux on order to evaluate the server performance in both
environments.  The hardware for each subsequent runs is identical, and
I also tried to keep the software configuration as similar as possible
(same versions of packages installed, same services enabled/disabled
etc.)  To test the performance of httpd I am using httperf with either
persistend and non-persistent connections.  When persistent
connections are enebled, I get very close performance on xenolinux to
native Linux, but when they are disabled the server performance over
xenolinux really suffers.  To give you a rough estimates how bad it is
here are some numbers.

persistent enabled   reply rate native                  xenolinux
4000 req/sec                   3900 rep/sec                700 rep/sec
persistent disabled         
4000 req/sec                   3950 rep/sec                3950 rep/sec

I understand why the case of persistent connections performs better
than the non-persistent, however in the former case httpd performance
under xenolinux is buffeling to me.

I suspect it is due to misconfiguration rather than xen issue and I
will appreciate if some of you provide any advices on what needs to be
checked.

The modifications that I have made to the kernel configuration of
linux, dom0 and dom0 are the following
# enable tcp time-wait recycling
echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle

#disable tcp timestamps 
echo 0 > /proc/sys/net/ipv4/tcp_timestamps

# increase the number of local ports that are available for use
echo 5000 65535 > /proc/sys/net/ipv4/ip_local_port_range

max number of open file descriptors for each processor is increased to 32K. 

Native linux runs FC2 2.8.1 kernel that was compiled with different
configuration than  2.6.8.1-xen0 and 2.6.8.1-xenU. (perhaps the first
place to check?)

nayden


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel