* Nicholas Piggin <npig...@gmail.com> [2017-04-04 09:52:07]: > On Tue, 4 Apr 2017 07:54:12 +1000 > Anton Blanchard <an...@ozlabs.org> wrote: > > > From: Anton Blanchard <an...@samba.org> > > > > The core of snooze_loop() continually bounces between low and very > > low thread priority. Changing thread priorities is an expensive > > operation that can negatively impact other threads on a core. > > > > All CPUs that can run PowerNV support very low priority, so we can > > avoid the change completely. > > This looks good. I have HMT_lowest() which does alt feature patching > we can use for pseries and default idle code.
Alternatively, if we are going to set priority only once in various other places, HMT_low(); HMT_very_low(); should not add to extra cycles. Let me code that up. --Vaidy
