Building credit-safe GPU queues | webtunel-gpu blog

Reserving credit before GPU work starts is the difference between a billing surface you can trust and a surprise invoice. Here is how Webtunel does it.

The overspend problem

Raw GPU marketplaces bill for wall-clock time on an instance, not for the work you intended to run. If a task hangs, loops, or a worker forgets to tear down, the meter keeps running.

Without a credit layer in front of the queue, the first time you learn about overspend is on the invoice.

Reserve before you run

Webtunel reserves estimated cost from a prepaid balance the moment a task is enqueued. If the balance is too low, the task is rejected before any GPU boots.

Reservation makes cost a precondition of execution instead of a consequence of it.

Settle on real usage

When a task completes, the runtime settles the reservation against actual instance usage and releases the difference back to the balance.

Cancellation releases the unconsumed reservation immediately, so a cancelled task never keeps holding credit.