Not sure how cost should be measured, but potential consequences like latency (milliseconds or seconds of communication delay) and/or failure to deliver a message would qualify as costs.
Example scenario (probably not a worst case):
1. HomeSeer polls a z-wave device (maybe a thermostat).
2. At the same time (or nearly so), let's say a z-wave motion sensor triggers. Let's say HomeSeer is supposed to receive the z-wave message from the motion sensor, and then (as part of the ensuing event) send a z-wave message to a light to turn on.
3. Suppose the z-wave thermostat polling collides with the z-wave motion sensor trigger, and so both messages are lost.
Simple enough, right? At a minimum, there's going to be some amount of latency incurred to make things right that wouldn't have been incurred if the polling hadn't been happening. I would define that extra amount of latency (whether a little or a lot) as part of the possible cost incurred by polling.
"So what?" you say. i.e. how big a magnitude can those costs be in the real world?
It seems that many HomeSeer users intuit a cost to polling and so try to keep their use of polling to a minimum. I'm just wondering what those costs actually are.
For me, there are certain tasks that absolutely need to be extremely low latency or they create a WAF that "something isn't right" with the system. A simple example of that is pressing a switch that turns on a light. I'm not sure what the exact threshold is, but that all probably needs to happen within around, say 100ms for there not to be a noticeable delay. If HomeSeer is in the middle of it, then that gives only 50ms for HomeSeer to receive the message and lookup the events triggered, and then 50ms to send out the z-wave "turn on the light" trigger. So, how many milliseconds of airtime does z-wave message take? If it's, say 50ms, then really any amount of delay (incurred because of polling collisions or otherwise) would lead to the perception of unacceptable latency, and therefore low WAF.
I'm making up those numbers to illustrate the point. I'd like to know what the real numbers are. Even if z-wave is in many ways a black box, I shouldn't need to guess about this or do forensic experiments to find the answer. It's relevant.
Example scenario (probably not a worst case):
1. HomeSeer polls a z-wave device (maybe a thermostat).
2. At the same time (or nearly so), let's say a z-wave motion sensor triggers. Let's say HomeSeer is supposed to receive the z-wave message from the motion sensor, and then (as part of the ensuing event) send a z-wave message to a light to turn on.
3. Suppose the z-wave thermostat polling collides with the z-wave motion sensor trigger, and so both messages are lost.
Simple enough, right? At a minimum, there's going to be some amount of latency incurred to make things right that wouldn't have been incurred if the polling hadn't been happening. I would define that extra amount of latency (whether a little or a lot) as part of the possible cost incurred by polling.
"So what?" you say. i.e. how big a magnitude can those costs be in the real world?
It seems that many HomeSeer users intuit a cost to polling and so try to keep their use of polling to a minimum. I'm just wondering what those costs actually are.
For me, there are certain tasks that absolutely need to be extremely low latency or they create a WAF that "something isn't right" with the system. A simple example of that is pressing a switch that turns on a light. I'm not sure what the exact threshold is, but that all probably needs to happen within around, say 100ms for there not to be a noticeable delay. If HomeSeer is in the middle of it, then that gives only 50ms for HomeSeer to receive the message and lookup the events triggered, and then 50ms to send out the z-wave "turn on the light" trigger. So, how many milliseconds of airtime does z-wave message take? If it's, say 50ms, then really any amount of delay (incurred because of polling collisions or otherwise) would lead to the perception of unacceptable latency, and therefore low WAF.
I'm making up those numbers to illustrate the point. I'd like to know what the real numbers are. Even if z-wave is in many ways a black box, I shouldn't need to guess about this or do forensic experiments to find the answer. It's relevant.
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