It's totally player dependent. If you approach a hacking task with a fixed objective in your mind it's, See the Thing, Hack the Thing, if host Search for the Thing, then Do the Thing. If you don't have an objective and ask the GM open ended questions and just do random things, it's like any complex encounter and can take hours. Same thing can happen if the GM indulges the Face character or a Rigger character.
If you're hacking a Commlink to get the next plot point the GM shouldn't even bother with dice, a typical hacker will have triple to Quadruple the dice pool of an unattended device. It's like making the characters roll to read a note.
About the only time I ask for rolls is for Matrix legwork, and hosts. If its a really high rated device, or we're in combat passes or some other high pressure situation, sure. Hacking the lock on the back door of a warehouse? Done. Unless the device is slaved to a PAN or a Host, its got 4 Dice.
If the Decker is rolling a bunch of dice and asking questions, the GM should start going around the table and asking "Okay, while the Decker is checking out stuff, what do you do?" That way if folks want to move things along they can. Put it in the hands of the Players.