What is the speed of M66

M66 is used to wait for an input to change state.

In the documentation is says:
In LinuxCNC these inputs are not monitored in real time and thus should not be used for timing-critical applications.

Would "real time" be classed as base-thread speed ??
Would M66 typically run at servo-thread speed, say a 1 Khz loop ??

I see M66 is part of the motion module which is set up in hal with:
loadrt motmod [base_period_nsec=period] [base_thread_fp=0 or 1] [servo_period_nsec=period] [traj_period_nsec=period] [num_joints=[1-9]] [num_dio=[1-64]] [num_aio=[1-64]] [num_spindles=[1-8]] [unlock_joints_mask=jointmask]

So would:
[servo_period_nsec=period] 
determine how fast M66 would monitor the pin state.

I am somewhat puzzled by the statement, I actually did think that M66 was sampled at the servo-thread rate. (not base thread)

Cheers Andy.

Guess I'll just have to hook up a logic analyser and do some testing to check for repeatability of timing on physical I/O.
It's a bit frustrating when the docs tell you what it isn't and not what it is LOL.

Might be better doing this type of thing in Classicladder which I believe runs at servo thread rate. Can hopefully get 1 millisecond loop cycle.

Keith