On 26 November 2013 12:51, Walsh, Benjamin <benjamin.wa...@windriver.com> wrote: > I was looking at using WFE on QEMU, found that it is > implemented as a NOP, googled and I found this thread. > > I am not using this for SMP, simply to implement sleep, so the busy > loop is conceptually OK. Except, of course, that QEMU floors the > host CPU at 100% in the idle loop.
FWIW, Linux uses WFI for its idle loop: http://lxr.linux.no/#linux+v3.12.1/arch/arm/mm/proc-v7.S#L64 If you're in a position to recode your idle loop to WFI instead of WFE that would be a workaround, because QEMU does halt the guest cpu on WFI, so we won't burn host CPU in a WFI-based idle loop. -- PMM
