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Angel_Lopez_116's avatar
Angel_Lopez_116
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Mar 18, 2015

iRule development: subtable spreading among TMMs

Hi,   I'm trying to understand the best way to design an iRule that will need to handle a lot of table entries and do that fast, as we're talking about rate limit on client connections.   I've ...
application delivery
cmp
design
devops
iRules
LTM
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Angel_Lopez_116's avatar
Angel_Lopez_116
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Mar 18, 2015

Hi nitass. My Viprion system has two 2150 blades installed, so I got 2 CPUs, 4 physical cores each, so 8 physical cores. That value of 8 is what I'm getting with the TMM::cmp_count variable so I guess that 8 would be my available "computing units".

 

As the CPUs in the B2150 are HT+ I'd get 2 threads per core, but as you said, from 11.5.0 1 thread is dedicated to data plane tasks and the other thread to control plane tasks. I guess that iRule execution is a data plane task, so I'd stick with that value of 8 for my "processing units".

 

If I'd have to design my iRule from scratch, and after reading that each subtable will be handled by a core, I'd choose to use maybe TMM::cmp_count subtables, but it seems that is recommended to use N * TMM::cmp_count being N=3 in the example iRule... I don't get why 3 and not other value... I guess that it's just to get several smaller subtables per core, but... is it 3 a magic number? any documentation about it?

 

Thanks!