jhgg

When you consider the problem from first principles, understand how the CPU that runs the program actually processes the data, are aware of things like cache locality, vectorization, etc... and have good placement, preemption, bin packing, and defragmentation algorithms, you learn that in the limit, milliseconds is all you need.

When you are responsible for the scheduling of ~millions of GPUs, every second starts to add up, and you realize that doing this correctly very quickly pays for itself.

Consider a large training run that takes 200k GPUs, if it takes 5 minutes to schedule that job, create pods, etc, that's ~16.6k GPU hours wasted. At a market rate of $11/gb300 GPU hour, that's ~$185k of wasted compute in scheduling overhead.

This means that if say a job requesting GPUs is submitted with a given topology constraint, we would already computed the physical nodes that satisfy the topology requirement, and begun preemption / begun spinning up processes on the target machines within a few milliseconds of the job being submitted. If there were no preemptions required (which means we need to first wait for graceful termination), the job is fully scheduled in the blink of an eye, whether it's on tens or hundreds of thousands of GPUs.

At work, we have built something very similar, a custom topology aware scheduler for workloads, and the most interesting things about such a project are entirely absent from this article, making it more of a fluff/marketing piece than an actually interesting technical blog in this area.

Our next iteration of this scheduler aims to scale to O(millions) of GPUs, with a scheduling cycle time measured in the milliseconds.

This is rarely a problem in practice however.

    > government passes law that requires companies to age verify users
    > said government provides no way to actually verify a human's age
    > hilarity ensues

At my last job we resized a very large amount of images every day, and did so for significantly cheaper (a fraction of a cent for a thousand images).

Am I missing something here?