[httperf] httperf doesn´t generate desi red request rate

Joerg Beyer job@webde-ag.de
Wed, 03 Dec 2003 16:17:07 +0100


Florian Berger wrote:
> Hi to all,
> 
> I encounter a problem with httperf: It does not generate the request
> rate I want it to do.
> 
> I´m testing a site involving CGI and generate (just for the example) 50
> requests at a increasing rate. No timeouts are involved.
> 
> With no rate, httperf reports to issue 2.7 req/s. I take this as a
> measure of what the webserver can handle easily.

to  be correct: 2.7 request per sec. is the average.
> 
> The second test runs with --rate=2. According to the value above, this
> should be no problem. httperf reports 2.0 req/s and nearly the same
> connection time values, as expected.

this request rate may a problem or not. If you have a test, that runs
a few minutes and gives x req/sec. at average, then this server
may very well fail if you stress test it with a constant request
rate below x req/sec.
> 
> Now I increase the load very slightly: --rate=3. But now httperf still
> reports it run at a request rate of 2.7 req/s.
> 
> Last test: --rate=5. Still got 2.7 req/s.
> 
> You can find the test reports at
> http://home.arcor.de/florib/rate-tests.txt

ok, now I see: you ran the test much to short. The man page
recommends at least 150 seconds.
> 
> As I understand it, httperf should _send_out_ requests at the given
> rate, even if the server cannot _handle_ them. But it obviously does
> not, preventing me to run useful tests with som dozens requests a
> second and some thousand requests in total. Any ideas why?
> 
> 
> My setup:
> 
> Server: Celeron 300 MHz, 98 MB RAM, Linux 2.2.16, Apache 1.3, mod_perl,
> Realtek 8029AS 10 MBit NIC
> 
> Client: Pentium 166 MHz, 64 MB RAM, Linux 2.2.16, httperf 0.8, Realtek
> 8029AS 10 MBit NIC

I usually recommend to take the faster machine as _client_, not as
_server_, since generation of the request may very well be the
harder part :-)

are there any network errors? /sbin/ifconfig should tell you
about that.

> 
> Connected via 10baseT, Twisted Pair crossover cable
> 

     hope this helps
     Joerg