Highlighted
Established Member.
168 views

Load Generator causes latency

Are there any basic steps to follow on how to investigate when client experience latency caused by the Load Generator?

 

My client discovered a latency not noticed before after testing.

0 Likes
2 Replies
Highlighted
Absent Member.. Absent Member..
Absent Member..

Re: Load Generator causes latency

Mee to facing the problem when I use Controller+Load Genrator as one machine.

 

Note: PC not recommends to use both as one machine.

0 Likes
Highlighted
Absent Member.. Absent Member..
Absent Member..

Re: Load Generator causes latency

You bring up a very interesting concern and one that I have written about in the LR\PC Blogs recently.  You can read the entire article here:

 

http://h30499.www3.hp.com/t5/HP-LoadRunner-and-Performance/Are-the-tools-that-you-are-using-to-test-your-application/ba-p/6585000

 

Basically if you find that your LG's are impacting the results of your test, your test is essentially a bust.  The key to preventing this is to know the footprint of each of your scripts and not just memory but also CPU.  If your LG CPU ever goes over 80% you can not be certain the results are accurate.

 

PC automatically monitors hosts and you can find the monitors while running the load test.  PC will also alert you if the CPU ever goes over 80% while the test is running.  Remember though that PC only pulls measurements every 5 seconds so even if you are hovering around 80% I would be concerned.

 

For LoadRunner you will need to monitor the LG's manually and you will want to monitor the available MB of memory as well as CPU.

 

There are two and sometime three other finite resources that an LG could run out of while running a load test.  Network Bandwidth, Disk IO, and for graphics based protocols GDI resources.  The solution for every one of these is the same, reduce the number of virtual users running on that LG until you are not running out of whatever finite resource is being consumed.  This requires testing your scripts in advance.

 

Finally, if you have your controller and LG be the same machine, this is strongly discouraged.  While there is not direct formula for determining exactly how many less virtual users you will be able to run I would suggest that it is at least 1/2.  In other words, if your LG could run 100 virtual users if it was alone, running on the same machine as the controller you may only be able to run 50 or less.

 

Hope this helps answer your question.

 

Regards,

 

Craig Drummond

HP SW Premier Support, Technical Account Manager - ALM Products.

The opinions expressed above are the personal opinions of the authors, not of Micro Focus. By using this site, you accept the Terms of Use and Rules of Participation. Certain versions of content ("Material") accessible here may contain branding from Hewlett-Packard Company (now HP Inc.) and Hewlett Packard Enterprise Company. As of September 1, 2017, the Material is now offered by Micro Focus, a separately owned and operated company. Any reference to the HP and Hewlett Packard Enterprise/HPE marks is historical in nature, and the HP and Hewlett Packard Enterprise/HPE marks are the property of their respective owners.