Re: [Pound Mailing List] FreeBSD and failed requests

     I've been thinking about this over the weekend but avoided  
working on it until now.  My assumption was that Pound did round- 
robin based on that fact that when I don't set any session  
configuration, if I throw 1000 connections at it with two IPs  
configured as backends, it roughly gets divided between the two.   
That scenario is also the one which shows a ton of failed  
connections, and this strange error.  After I define some sort of  
session, IP in the case of sorting this out, then all the traffic  
gets directed to the same server and the failures disappear.  We have  
to keep track of sessions anyway so if that's the solution it's  
perfectly acceptable.
     Anyway, using the session tracking stopped those failure  
errors, but still left me with relatively low request handling.   
Having tried different networking gear, computers, and OSes and seen  
the same thing across the board this morning I decided to eliminate  
the physical networking entirely.  This is on one machine, looping  
back to itself.  Apache listens on 80, Pound listens on 8080 with a  
single backend of 127.0.0.1 being defined:

First, hitting Apache directly on localhost, port 80:

Server Software:        Apache/2.2.2
Server Hostname:        127.0.0.1
Server Port:            80

Document Path:          /
Document Length:        16 bytes

Concurrency Level:      10
Time taken for tests:   1.43769 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      264000 bytes
HTML transferred:       16000 bytes
Requests per second:    958.07 [#/sec] (mean)
Time per request:       10.438 [ms] (mean)
Time per request:       1.044 [ms] (mean, across all concurrent  
requests)
Transfer rate:          246.22 [Kbytes/sec] received

Connection Times (ms)
              min   avg   max
Connect:        0     0    1
Processing:     1     9   19
Total:          1     9   20


Second, hitting Pound on localhost 8080 which forwards to the just  
tested Apache on localhost 80:

Server Software:        Apache/2.2.2
Server Hostname:        127.0.0.1
Server Port:            8080

Document Path:          /
Document Length:        16 bytes

Concurrency Level:      10
Time taken for tests:   3.282322 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      264000 bytes
HTML transferred:       16000 bytes
Requests per second:    304.66 [#/sec] (mean)
Time per request:       32.823 [ms] (mean)
Time per request:       3.282 [ms] (mean, across all concurrent  
requests)
Transfer rate:          78.30 [Kbytes/sec] received

Connection Times (ms)
              min   avg   max
Connect:        0     0    1
Processing:    10    31   59
Total:         10    31   60


     What's "strange" about the slow request handling is that I can  
up the concurrency level, and Pound will continue to handle it with  
little to no dropoff.  But for whatever reason it's peak performance  
caps off well below what the server behind it can handle.  Before  
coming into work this morning I tried this same loopback test on a  
machine of mine at home and direct to Lighttpd had a reqs/s rate of  
1800, while once it routed through Pound and then to Lighttpd the  
reqs/s rate dropped to 430.  Disabling all logging got me an extra 20  
reqs/s.  I just tested Pound on a CentOS 4.2 machine, a P3 700, using  
the loopback style again.  Direct to Lighttpd, 1600 reqs/s.  To  
Pound, forwarding to Lighttpd on loopback, 380 reqs/s.  I'd expect  
some dropoff but nothing quite that severe.
     I'm going to be working on this most of today so if there are  
some suggestions or requests of things for me to do, I'm open to  
trying them.

On May 8, 2006, at 9:31 AM, Robert Segall wrote:

> On Fri, 2006-05-05 at 16:24 -0700, Scott Larson wrote:
> > May  5 14:52:58 fencer pound: backend 10.10.10.36:80 connect:
> > Operation not permitted
>
> That is strange. From the man 2 connect (see the section on errors):
>
>     EACCES, EPERM
>         The user tried to connect to a broadcast address without   
> having
>         the  socket  broadcast  flag  enabled  or the connection  
> request
>         failed because of a local firewall rule.
>
> Any idea how this could happen?
>
> BTW: Pound doesn't do round-robin...
> --
> Robert Segall
> Apsis GmbH
> Postfach, Uetikon am See, CH-8707
> Tel: +41-44-920 4904
>
>
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> 2006/2006-05/1146767005000/1147105869000

--
Scott Larson
Network Administrator
IOWA Interactive
4212 Glencoe Ave
Marina Del Rey, CA 90292

t 310.823.8238
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