On Thu, 26 Oct 2023 16:50:16 +0900 Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> wrote: > > The goal is to prevent a thread / vCPU being preempted while holding a lock > > or resource that other threads / vCPUs will want. That is, prevent > > contention, as that's usually the biggest issue with performance in user > > space and VMs. > > I think some time ago we tried to check guest's preempt count on each vm-exit > and we'd vm-enter if guest exited from a critical section (those that bump > preempt count) so that it can hopefully finish whatever is was going to > do and vmexit again. We didn't look into covering guest's RCU read-side > critical sections. > > Can you educate me, is your PoC significantly different from guest preempt > count check? No, it's probably very similar. Just the mechanism to allow it to run longer may be different. -- Steve
