Forum Discussion
Yado_52136
Nimbostratus
NimbostratusAbout the parallel processing of iRules
iRules-A and iRules-B are set as VirtualServerA and B, respectively.
The loop of the communication A is carried out by iRules-A (while sentence), and FLG of a global variable is made t...
Joe_Hsy_45207Nimbostratus
Nimbostratus
In general, having a tight loop such as in iRule-A (without sleep calls) is probably not a great idea. For my own curiosity, I did a quick experiment and it looks like it grinds TMOS to a halt until eventally it timesout which took a long time (on 9.2.5). This is a bit scary as a badly written iRule could easily bring the whole Big-IP down.
It might be a good enhancement to the iRule engine to more aggresively prevent runaway iRules like this by capping execution cycles.
Also, it looks like tcl commands "after" and "vwait" are both disabled for iRule so there isn't a way to do any kind of "sleep", so there isn't a way to wait with a lesser impact.
But to answer the more general question, indeed iRule executions have to be in parallel or else the performance would be horrible with many concurrent requests. Are you just trying to verify parrallel execution or do you have a specific scenario in mind?
//Joe
