hIOmon SSD Performance Monitor - Understanding desktop usage patterns.

[Computurd]

very interesting stuff here. interested in your high QD numbers, thinking here of reasons... 10 channels per device, three devices, total of 30 channels. that would be a QD of 50 per-channel roughly...might be explainable?? but doubt it. i think the system sees the devices as one drive.

NCQ allows the system to ask for I/O in a different manner, optimized and designed for HDD, it still works phenomenal wonders with SSD.

The shopping analogy applies very well here, for those who aren't sure of its functions:

Imagine you have a shopping list of 50 items, and you go to the grocery store. if you would go and find the first item, then go to the checkout lane and pay for it, then go back, get another item, then go pay for it, repeat repeat repeat 50 times, that is in essence how I/O operations work without NCQ. the system waits for the I/O request to 'return' before it asks for another. it has its list, but it wants it one at a time.
NCQ gives you the list, then tells the device to go get it, in any order, all at once. it doesn't care what order the "items" are obtained, it just wants them all to return at once. it does not wait for return verification.
so....much like taking the 50 item list shopping, go get all 50 items in the most efficient order, THEN go check out.
much faster, and more efficient.
NCQ works exceedingly well with SSD. So...maybe the higher QD are the result of these 'lists' being served so quickly, or being dumped on to the controller of the SSD so quickly. what if it is counting each request on the list as a QD? so one list of 50 would be a 50 QD spike? maybe longer 'lists' are served to devices that can return the 'lists' faster....maybe these higher QD numbers are the result of VERY efficient NCQ being run by the system.

god who knows. interesting any way you slice it
how would you prove such a theory though?

i guess that has become my side-mission here. maybe my main mission! to find how NCQ 'lists' are monitored as QD would be very interesting. what if there is a curveball here though...what if one 50 item list, only counts as ONE QD???