On Mon, Sep 18, 2023 at 01:59:50PM +0200, Alexander Graf wrote: > The problem with MWAIT is that you don't really know when it's done. This isn't really a problem. MWAIT is allowed (expected even) to return early. REP;NOP is a valid implementation of MWAIT. MWAIT must not delay waking (much) after either: - write to monitored address - interrupt pending But it doesn't say anything about not waking up sooner. Now, obviously on real hardware you prefer if MWAIT were to also do the whole C-state thing and safe your some actual power, but this is virt, real hardware is not a concern and wakeup-timeliness also not much. IIRC the ARM64 WFE thing has a 10khz timer or something it wakes from if nothing else. So I suppose what I'm saying is that: nanosleep(100000) might be a suitable MWAIT implementation. It's virt, it sucks anyway :-)
