Hello all,

I setup a pound server in front of our .NET server (which we're
transitioning from) and ran some tests to see whether our QPS and
responsiveness were affected. The results showed a weird behavior at
high concurrency.

Here are the results: http://208.109.51.74/share/performance_tests.html

Three test sets. One at low concurrency (3 threads), one at medium (10
threads) and one at high (30 threads). Each test set included a run
directly against the web server, and one through pound.

At low concurrency, requests per seconds, and time per request were very
similar between direct and pound. When I ran with 10 threads, I noticed
that the numbers starting differing, but that while 98% of the requests
had a similar time per request, about 2% took more than 5 seconds!
Things started getting worse with the higher concurrency test. At 30
threads, At least 5% of the requests were taking longer than 5 seconds
to complete.

I am using ab for the tests, and all commands looked like: ab -c 30 -n
3000 http://pound/

It seems to me like some responses are being held hostage while others
are being served. Is that expected? This is somewhat concerned, as we do
see averages exceeding 20 requests for parts of the day.

Any insight would be appreciated. I like pound a lot, but this is very
concerning.

Khaled

On Sun, 2007-04-29 at 19:33 -0400, Khaled Hassounah wrote:[...]

You don't say on which system Pound runs, which is important. Pound is
only as good as the underlying threads library. If the library is not
quite up to par then Pound performance will suffer.

This sort of problem occurs quite often on older Linux systems (kernel
2.4 or earlier, and some RedHat versions) and on some BSD systems
(user-space threads). There is no easy cure except an upgrade.[...]

Robert,

I've seen the same behavior on our systems.  We're running pound on 
RedHat Linux ES4, Kernel 2.6.9-42.0.10.  What exactly would we need to 
upgrade?

Robert Segall wrote:[...][...][...]

And ours is:

Linux version 2.6.9-5.ELsmp (bhcompile(at)decompose.build.redhat.com) (gcc
version 3.4.3 20041212 (Red Hat 3.4.3-9.EL4)) #1 SMP Wed Jan 5 19:30:39
EST 2005

I am assuming this is featured enough. no?

Khaled

Albert wrote:[...][...][...]