[httperf] output - num-calls and num-conns difference

neubyr neubyr at gmail.com
Wed Feb 26 08:50:51 PST 2014


Thanks for the detailed explanation Martin. I checked server configuration
and it's not supporting persistent connections (apache - KeepAlive off).
Now I understand why requests and replies are different. But I am not
following why httperf made only 8 requests in the second case. In the
second case, CLI options are "--wlog=n,$HOME/tmp/reqs.txt_httperf --rate=10
--num-conns=4 --num-calls=6 --hog", so I was expecting 24 requests
(num-conns * num-calls). It seems like it's dependent on server
configuration as well, but I am not sure how.. For example, when I used
same options against www.google.com, I got "Total: connections 4 requests
24 replies 24 test-duration 0.533 s".

-N




On Wed, Feb 26, 2014 at 5:26 AM, Arlitt, Martin <martin.arlitt at hp.com>wrote:

>  Hi
>
>
>
> The web server you are testing does not appear to support persistent
> connections. That is why in your first case the output says "10
> connections" were created, "20 requests" were made but only "10 replies"
> were received, and in your second case "4 connections" were created, "8
> requests" were made and only "4 replies" were received.
>
>
>
> What is happening is httperf establishes a connection with the server,
> issues its first call on that connection, receives a reply to that call,
> then quickly issues its second call, before httperf receives the server's
> indication that it wants to close the connection (which the server may make
> via a TCP FIN packet that httperf won't see directly rather than an HTTP
> header that httperf would see directly). You may have to use a tool like
> tcpdump to monitor the network traffic to see this behavior. If the server
> is attempting to close the connection via an HTTP header, then would could
> also try the -print-request and -print-reply options in httperf to see what
> is going on.
>
>
>
> Thanks
>
> Martin
>
>
>
> *From:* httperf-bounces at linux.hpl.hp.com [mailto:
> httperf-bounces at linux.hpl.hp.com] *On Behalf Of *neubyr
> *Sent:* Tuesday, February 25, 2014 11:42 PM
> *To:* httperf at linux.hpl.hp.com
> *Subject:* [httperf] output - num-calls and num-conns difference
>
>
>
>
>
>
>
> When I run httperf with following options, the output is easy to
> understand.
>
>
>
> Options: Make total 10 connections (num-conns) at rate of 10 (rate)
> connections/second with 2 request calls per connection (num-calls).
>
> Output: 10 connections with 20 request calls
>
>
>
>     httperf -v --server www.example.com--wlog=n,$HOME/tmp/reqs.txt_httperf --rate=10 --num-conns=10 --num-calls=2
> --hog
>
>     Total: connections 10 requests 20 replies 10 test-duration 1.575 s
>
>
>
>
>
> However, when I use following options, httperf output, output is confusing.
>
> Options: Make total 4 connections (num-conns) at rate of 10 (rate)
> connections/second with 6 request calls per connection (num-calls).
>
>
>
>     httperf -v --server www.example.com--wlog=n,$HOME/tmp/reqs.txt_httperf --rate=10 --num-conns=4 --num-calls=6
> --hog
>
>     Total: connections 4 requests 8 replies 4 test-duration 0.455 s
>
>
>
>
>
> It seems like when num-calls is greater than num-conns, number of requests
> made are 2*num-conns.
>
>
>
> I am not following why num-calls be greater than num-conns. Am I missing
> anything?
>
>
>
> -thanks,
>
> N
>
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