Hello, On Fri, Aug 12, 2022 at 04:54:04PM -0400, Felix Kuehling wrote: > In principle, I think IRQ routing to CPUs can change dynamically with > irqbalance. I wonder whether this is something which should be exposed to userland rather than trying to do dynamically in the kernel and let irqbalance or whatever deal with it. People use irq affinity to steer these handlings to specfic CPUs and the usual expectation is that the bottom half handling is gonna take place on the same cpu usually through softirq. It's kinda awkard to have this secondary assignment happening implicitly. > What we need is kind of the opposite of WQ_UNBOUND. As I understand it, > WQ_UNBOUND can schedule anywhere to maximize concurrency. What we need is to > schedule to very specific, predictable CPUs. We only have one work item per > GPU that processes all the interrupts in order, so we don't need the > concurrency of WQ_UNBOUND. Each WQ_UNBOUND workqueue has a cpumask associated with it and the cpumask can be changed dynamically, so it can be used for sth like this, but I'm not yet convinced that's the right thing to do. Thanks. -- tejun
