Perfomance gain of using HTTP Classes over iRules

Naman,

 

 

I would be surprised if only 1000 conns/sec put any real stress on the LTM. You probably hit that goal using both versions of the iRule, so the throughput would naturally be the same in both cases. Throughput would only be affected if the delay incurred by one of the rules was so great that it affected TCPs windowing system, and that won't be the case here.

 

 

Did you actually enable timing in the iRule and view the stats after the test had completed? The timing statistics should have told you which iRule used more CPU time, even if the test wasn't heavy enough to result in a visible difference. The average 'cycles' for each iRule should be a good indicator of which one is using more CPU time. I would record the average cycles used for each iRule across several tests on each iRule, then create an average of the averages. This should give you a good idea of which iRule is performing better even if you can't tell using simple statistics like throughput. I'd also ensure that the timing command is providing the output you expect by running at least one test using trivial iRule that checks for whether the request is for a 'jpg' or not, but uses the same pool either way. The average cycles used in that test should be far lower than the more complex iRules.

 

 

 

Some points to remember when running your tests:

 

- Always clear your iRule stats between tests: "b rule all stats reset"

 

- Run a 'bigstart restart tmm' between tests. (will disrupt traffic, do not do this on a production system)

 

 

 

 

Hope this helps.

 

 

 

thanks,

 

--jesse