[OpenSTA-devel] [ opensta-Bugs-696350 ] OpenSTA limit of 1664 vusers/users ?

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Bugs item #696350, was opened at 2003-03-03 00:18
Message generated for change (Comment added) made by dansut
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110857&aid=696350&group_id=10857

>Category: HTTP Replay
>Group: Behavioral
Status: Open
Resolution: None
Priority: 5
Submitted By: Ranjit Shewale (jcrvs)
>Assigned to: Daniel Sutcliffe (dansut)
Summary: OpenSTA limit of 1664 vusers/users ?

Initial Comment:
OpenSTA does not display and message when it 
reaches the user/vuser limit of 1664. 
As the test continues the vusers go on loading to a limit 
of 1664 and donot increase beyond that for the http or 
web scripts. 
This is observed on platform as Windows NT Server 4.0 
with SP6.
The marked observations (reported by perfmon) as the 
1664 user limit are as follows:-
1. Handle count for the TExecutor_htp.exe - it rises 
gradually as the test starts till it reaches the saturation 
point and then remains stable (drops to 0 when the test 
stops). Now the saturation point corresponds to the 
point where cpu utilization starts increasing and later 
reaches 100%.
2. Context switches of system are high in the region 
where the cpu utilization is 100%.
3. Exception dispatches per sec are high in the region 
where the cpu  utilization is 100%.
4. File Control Operations/sec are high in the region 
where the cpu  utilization is 100%

(My conculsion: 
This makes me conclude that the NT machine 'handle 
limit' is probably around 3734 or so and when opensta 
requests more handles to the system the system starts 
returning exceptions, hence the exceptions observed are 
high here as mentioned in point 3 above

The NT help for 'File Control Operations/sec' 
says 'operations usually include file system control 
requests or requests for information about device 
characteristics or status'. This could alos be one of the 
reasons for the problem. Something like opensta is 
internally making calls to get the status of cretain 
threads etc and results into pushing the server queue to 
higher value. This in turn increases the context switches 
amongst threads)

For other non-http scripts with huge delays as 10 
minutes or so, the OpenSTA is able to exceedd the user 
limit of 1664.

There is no documentation that mentions the above 
1664 vuser limit/bug.

The perfmon file is attached for reference. Unzip the file 
and open it using the NT4.0 perfom tool.

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>Comment By: Daniel Sutcliffe (dansut)
Date: 2003-04-29 22:05

Message:
Logged In: YES 
user_id=19748

More info can be added and read at:
http://portal.opensta.org/faq.php?topic=BugsMaxVu

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Comment By: Ranjit Shewale (jcrvs)
Date: 2003-03-03 00:22

Message:
Logged In: YES 
user_id=721091

Sorry forgot to attach the file

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110857&aid=696350&group_id=10857