[httperf] Httperf client timeout while making progress

Martin Arlitt arlitt at granite.hpl.hp.com
Fri Nov 24 11:14:56 PST 2006


hi Chris

you are correct, there is a discrepancy between the behaviour and the
documentation.  more specifically, httperf does not appear to update the
timeout value for the fourth case, so in effect it will time out X seconds
after it starts waiting for the start of the reply, rather than from when
the start of the reply is received.

a fix that resets the timer each time a new packet in the reply is
received is:

diff -urN httperf-0.8/core.c httperf-0.8-fix2/core.c
--- httperf-0.8/core.c  2000-10-31 18:57:50.000000000 -0500
+++ httperf-0.8-fix2/core.c     2006-11-24 12:08:33.000000000 -0500
@@ -591,7 +591,12 @@
   while (buf_len > 0);

   if (s->recvq)
-    set_active (c->conn, &rdfds);
+    {
+      s->recvq->timeout = param.timeout + param.think_timeout;
+      if(s->recvq->timeout > 0.0)
+       s->recvq->timeout += timer_now ();
+      set_active (c->conn, &rdfds);
+    }
 }

a fix that sets the appropriate start time, but does not update for each
packet is

--- httperf-0.8/core.c  2000-10-31 18:57:50.000000000 -0500
+++ httperf-0.8-fix/core.c      2006-11-24 11:38:04.000000000 -0500
@@ -578,6 +578,12 @@
     {
       c = s->recvq;
       assert (c);
+      if(s->state == S_REPLY_STATUS)
+       {
+         c->timeout = param.timeout + param.think_timeout;
+         if (c->timeout > 0.0)
+           c->timeout += timer_now ();
+       }
       http_process_reply_bytes (c, &cp, &buf_len);
       if (s->state == S_REPLY_DONE)
        {


I think you want the first one.

please let me know if this works for you.

thanks

Martin

 On Fri, 24 Nov 2006, Chris Wilson wrote:

> Hi all,
>
> First of all, thanks for writing httperf! It looks like an excellent tool
> and most suitable for the kind of network performance tests and debugging
> that I'm currently doing (fixing university networks in Kenya).
>
> However, I think I've discovered a discrepancy between httperf's behaviour
> and the documentation. The man page says of the option --timeout:
>
>     Specifies the amount of time X that httperf is willing to wait
>     for a server reaction. [...] This timeout value is used when
>     establishing a TCP connection, when sending a request, when waiting for
>     a reply, and when receiving a reply. If during any of those activities
>     a request fails to make forward progress within the alloted time,
>     httperf considers the request to have died, closes the associated
>     connection or session and increases the client-timo error count.
>
> Now that makes perfect sense to me, and mirrors the way that I think a
> browser would work. My definition of "making forward progress while
> receiving a reply" is that packets continue to be received. So as long as
> the delay between packets (or TCP data delivery) does not exceed the
> timeout, httperf will not give up on the connection.
>
> However, I think that I have observed httperf behaving differently.
> Specifically, it seems to apply the --timeout to receiving the entire
> response. Therefore, if I specify a reasonable timeout of 30 seconds, and
> download a large page over a slow connection, httperf reports a timeout
> error, even though a browser would not.
>
> I've attached a pcap file and httperf debug log (level 3) as an example.
>
> If there is any choice over this behaviour, I would like to configure
> httperf to behave the way that I described above, i.e. not to time out the
> connection as long as it continues to receive packets.
>
> Thanks in advance for your help!
>
> Cheers, Chris.
> --
> (aidworld) chris wilson | chief engineer (http://www.aidworld.org)


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