This factor that we call contention is making me crazy...

This factor that we call contention is making me crazy...

Hello,

This factor that we call contention is making me crazy...

I have deleted my article on the scalability and 'contention',
because my equation doesn't work correctly...

Now my question is:

If you read carefully , you will see that Dr. Gunther is using this
model to predict scalability after he simulates a relatively small
number of vusers in LoadRunner ( because of licensing costs, it's
cost-effective) and after that he finds the coefficients of the
2nd-degree polynomial (quadratic equation) and then transform
those coefficients back to the USL parameters using the = b - a
and = a.

And then he is extrapolating with the USL model - from just
a small number of measured points - to higher loads
to predict scalability.

http://en.wikipedia.org/wiki/Neil_J._Gunther

But imagine that a large number of clients are making HTTP requests
to a website, this thing that we call logical contention and physical contention
are probabilistic, so, imagine that there is a lot of contention in a time
interval , internet clients may wait a time greater than 5 seconds , and
this is not good...

Hence, since the contention is probabilistic and the throuput can become
much slower when there is a lot of contention in a time interval ,
how can USL predict such a problem from just a small number
of measured points ???

Look at this:

http://perfdynamics.blogspot.com/2009/04/assessing-usl-scalability-with-mixed.html

Regards,
Amine Moulay Ramdane.
http://pages.videotron.com/aminer/

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