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From "Lincoln, Adym" <Adym.Linc...@LibertyMutual.com>
Subject RE: Too many TCP connections?
Date Fri, 10 Feb 2006 20:36:17 GMT
Fred,

I'm curious as I build a Test Plan to investigate this myself.  Did you
have multiple Thread Groups involved, each trying to create 30(+)
threads, or was it a single Thread Group trying to create 30(+) threads.

The more I think about this problem, the more I think it's related to
the Web Server...I.e. The fact that a CGI configuration allowed you to
create 50(+) threads while a DSO configuration would only allow 30(-).
This tells me that JMeter doesn't have a problem with creating 30(+)
threads, it's the web server that can't service the incoming requests...

I'm wondering what JMeter does when it receives an HTTP Response code
other than 200 (OK), 302 (redirect), or 404 (Not found).  Anyone know
what the HTTP Response code is from Apache when it's at MaxClients...in
other words the web server ain't gonna service you?  I'm wondering if
the JDK java.net.* component just throws up the "Address already in use:
connect" exception...


thx,

Adym Lincoln
I/S Corporate - I/S Internal Applications
603-245-8245
Ext : 58245
adym.lincoln@libertymutual.com

...
It's a bug planet...it's an ugly planet...ever feel like your software
project is going in the wrong direction.
...


-----Original Message-----
From: Fred [mailto:fredckp@yahoo.com.sg] 
Sent: Friday, February 10, 2006 10:20 AM
To: JMeter Users List
Subject: Re: Too many TCP connections?

Hi Lincoln,

No problem, thanks. I have resolved the issue.

It appear that JMeter was not able to cope with the initial 300ms set in

delay for each request. Also, probably I am performing the test in a
10/100 
LAN, hence the response time not realistic too.

I have further delay to 1000 ms and it appear to get over and failed at
50 
threads. I will probably set further delay, I think it should help.

Regards,
Fred
----- Original Message ----- 
From: "Lincoln, Adym" <Adym.Lincoln@LibertyMutual.com>
To: "JMeter Users List" <jmeter-user@jakarta.apache.org>
Sent: Friday, February 10, 2006 10:54 PM
Subject: RE: Too many TCP connections?


Fred,

Unfortunately, this is starting to go beyond my expertise with Jmeter
and Apache.  I've done some performance tuning of Apache and some work
with CGI and DSO configurations.  In this case, it sounds like there is
some in-depth research on Apache worker versus prefork configurations.



Adym Lincoln
I/S Corporate - I/S Internal Applications
603-245-8245
Ext : 58245
adym.lincoln@libertymutual.com

...
It's a bug planet...it's an ugly planet...ever feel like your software
project is going in the wrong direction.
...


-----Original Message-----
From: Fred [mailto:fredckp@yahoo.com.sg]
Sent: Thursday, February 09, 2006 10:12 PM
To: JMeter Users List
Subject: RE: Too many TCP connections?

Thanks for your quick response, once again..

- In a CGI configuration you're able to "exceed" 30 threads.
- In a DSO (module) configuration it breaks at ~ 30 threads.

Fred: This is correct, if I using a CGI module to load on, the Jmeter's
test
plan can even generate up to 50 threads.

What's you web server?  Apache, IIS, Tomcat, other?

Fred: It's an Apache built-in in CentOS.

It could be that you're web server is limiting the number of threads it
will create.  I know Apache has a couple of configuration settings that
define what and how many threads it will allow...

Fred: If the web server is limiting the thread, shouldn't it limit the
threads creation, when I'm loading the CGI module?

My guess is whatever port that the 30th thread is trying
to use is already in use.

Fred: Apart from the web server limiting the thread, if there is a
possibility that the JMeter cannot cope with the fast return response
within
the thread group for concurrent access that it breaks? May be I will try
to
add more delay in between request.

Regards,
Fred

-----Original Message-----
From: Lincoln, Adym [mailto:Adym.Lincoln@LibertyMutual.com]
Sent: Thursday, February 09, 2006 10:21 PM
To: JMeter Users List
Subject: RE: Too many TCP connections?


Just so I'm clear...
- In a CGI configuration you're able to "exceed" 30 threads.
- In a DSO (module) configuration it breaks at ~ 30 threads.

What's you web server?  Apache, IIS, Tomcat, other?

It could be that you're web server is limiting the number of threads it
will create.  I know Apache has a couple of configuration settings that
define what and how many threads it will allow...

Also, the Java exception in your original message reads:
<snip>
connect java.net.BindException: Address already in use: connect
 at java.net.PlainSocketImpl.socketConnect(Native Method)
</snip>

The java.net.* package is part of the JDK.  Thus, the exception is being
fired from the JDK, not JMeter.  JMeter is catching the exception and
reporting it.  My guess is whatever port that the 30th thread is trying
to use is already in use.  But, this doesn't rule out the possibility
that your Web server is limiting the number of threads...i.e. if the
30th thread is not allowed by the web server, and the JDK simply
"reports" this exception as "Address already in use.".  In other words,
the JDK could be reporting a "default" exception message because it
doesn't have a specific message for the web server's "No more threads
available" message.  Hope these last couple of sentences make sense...

I haven't seen anything in JMeter that allows you to control what
port(s) to use when creating threads.  There's probably a setting
though...i.e. start at port number XXXX and go up (or down) from there.


hth,


Adym Lincoln
I/S Corporate - I/S Internal Applications
603-245-8245
Ext : 58245
adym.lincoln@libertymutual.com

...
It's a bug planet...it's an ugly planet...ever feel like your software
project is going in the wrong direction.
...


-----Original Message-----
From: Fred [mailto:fredckp@yahoo.com.sg]
Sent: Thursday, February 09, 2006 5:00 AM
To: Lincoln, Adym; JMeter Users List
Subject: RE: Too many TCP connections?

Thanks for the response.

I have run the same tests Jmeter on 2 XP SP2 machines,
- AMD Athon 3000, 512mb RAM,
- Intel Pentium4, 2.8Ghz, 1024Mb RAM.

Both breaks consistently in the midst of 30 threads.

Brief TestPlans:
10 Threads
|_ 100 HTTP POST requests
20 Threads
|_ 100 HTTP POST requests
30 Threads
|_ 100 HTTP POST requests
40 Threads
|_ 100 HTTP POST requests
50 Threads
|_ 100 HTTP POST requests

I have successfully run above tests to a CGI script on server, and only
run
into issue when the CGI module is being changed to a DSO module on the
test
server.

Hence, it seems rule out my test machines are not able to generate the
amount of threads.

Regards,
Fred

-----Original Message-----
From: Lincoln, Adym [mailto:Adym.Lincoln@LibertyMutual.com]
Sent: Wednesday, February 08, 2006 10:05 PM
To: JMeter Users List; fredckp@yahoo.com.sg
Subject: RE: Too many TCP connections?


There's a good chance that it's related to the number of threads, not
TCP connections.  TCP connections typically utilize a "port" on your
machine.  Setting up a TCP connection probably doesn't use as many
resources as setting up the "thread" that is going to use that port.

There's also the possibility that XP's firewall is not allowing you to
use certain "port" numbers, but it doesn't sound that way, since you
indicate that it is "consistently" happening at the same point.

My guess, not knowing your machine specs, is that your machine simply
runs out of resources to create more threads...I had read an article two
days ago on JMeter having a similar issue at 25 threads...could have
sworn it was on the Server Side website, but I can't find it now.  In
the article, the author wanted to run a test with 100 threads, but it
broke down at around 25 threads...

hth,

Adym Lincoln
I/S Corporate - I/S Internal Applications
603-245-8245
Ext : 58245
adym.lincoln@libertymutual.com

...
It's a bug planet...it's an ugly planet...ever feel like your software
project is going in the wrong direction.
...


-----Original Message-----
From: Fred [mailto:fredckp@yahoo.com.sg]
Sent: Wednesday, February 08, 2006 6:23 AM
To: List, JMeter Users
Subject: Too many TCP connections?

I was running a test off a Windows XP platform, and it consistently
breaks
in the midst of thread.. with the following error..
I suspect it's too many TCP connections opened, is there a limit that I
can
open concurrently?

Any advice is very much appreciated.

Regards,
Fred

------------------------------------------------------------------------
----
----

2006/02/08 10:16:43 INFO  - jmeter.threads.JMeterThread: Thread 30
Thread
3-24 started
2006/02/08 10:16:43 ERROR - jmeter.protocol.http.sampler.HTTPSampler:
Can't
connect java.net.BindException: Address already in use: connect
 at java.net.PlainSocketImpl.socketConnect(Native Method)
 at java.net.PlainSocketImpl.doConnect(Unknown Source)
 at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
 at java.net.PlainSocketImpl.connect(Unknown Source)
 at java.net.Socket.connect(Unknown Source)
 at java.net.Socket.connect(Unknown Source)
 at sun.net.NetworkClient.doConnect(Unknown Source)
 at sun.net.www.http.HttpClient.openServer(Unknown Source)
 at sun.net.www.http.HttpClient.openServer(Unknown Source)
 at sun.net.www.http.HttpClient.<init>(Unknown Source)
 at sun.net.www.http.HttpClient.New(Unknown Source)
 at sun.net.www.http.HttpClient.New(Unknown Source)
 at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown
Source)
 at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown
Source)
 at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
 at
org.apache.jmeter.protocol.http.sampler.HTTPSampler.sample(HTTPSampler.j
ava:
424)
 at
org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSampl
erBa
se.java:514)
 at
org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSampl
erBa
se.java:503)
 at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:247)
 at java.lang.Thread.run(Unknown Source)

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