On Fri, 31 May 2019, Jiri Kosina wrote: > On Fri, 31 May 2019, Andy Lutomirski wrote: > > > 2. Put the CPU all the way to sleep by sending it an INIT IPI. > > > > Version 2 seems very simple and robust. Is there a reason we can't do > > it? We obviously don't want to do it for normal offline because it > > might be a high-power state, but a cpu in the wait-for-SIPI state is > > not going to exit that state all by itself. > > > > The patch to implement #2 should be short and sweet as long as we are > > careful to only put genuine APs to sleep like this. The only downside > > I can see is that an new kernel resuming and old kernel that was > > booted with nosmt is going to waste power, but I don't think that's a > > showstopper. > > Well, if *that* is not an issue, than the original 3-liner that just > forces them to 'hlt' [1] would be good enough as well.
Actually no, scratch that, I misunderstood your proposal, sorry. -- Jiri Kosina SUSE Labs
