Timing/CPU info for BigIP DNS WideIP iRules

I just realized yesterday (or put better, one of my students pointed it out to me...) that BigIP DNS doesn't seem to hold timing information on the execution of iRules. For LTM, this ("show ltm rule <irule name>") is a great way of seeing roughly how much CPU power is required per iRule, and if there's any optimization that can be done, (https://clouddocs.f5.com/api/irules/timing.html). 

For BigIP DNS iRules though, and specifically the iRules under the Wide IP configuration, this doesn't seem to be recorded. "show gtm rule <irule name>" show the number of executions, but not the timing info. I've tried to lookup any information about this, or a clear statement that this does not NOT happen, but no luck so far. 

So, does anyone know if this information is available and I'm just looking in the wrong place, or if there's any reason why this isn't recorded? And if not, is there another way in which this information can be obtained? 

Thanks!