--- Sent from my phone On 23/04/2015 8:10 pm, "Peter Maydell" <peter.mayd...@linaro.org> wrote: > > On 23 April 2015 at 04:37, Edgar E. Iglesias <edgar.igles...@gmail.com> wrote: > > I had a comment on the trapping of WFX, I recall not checking for > > has_work was causing a lot of exception round-trips when running > > XEN. To the point were things almost stopped working. > > For traps on WFE, or traps on WFI? If the former, we should > probably implement that as "never trap" since we don't actually > go into a 'low power state' for WFE (execution will always > continue even if there's no pending WFE event). > > -- PMM
Hi, I think it was for both, I can retest it to double check. Our (xilinx) tree tracks wfe wakeups. I agree that without tracking we better not trap.. When running emulated SMP with multiple nested SMP guests there are a lot of these events fired. The exception code paths down to hypervisors involve fairly long round trips. Cheers, Edgar
