On Thu, Sep 22, 2022 at 10:17 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > On Wed, Sep 21, 2022 at 09:48:13PM +0200, Borislav Petkov wrote: > > On Wed, Sep 21, 2022 at 05:00:35PM +0200, Peter Zijlstra wrote: > > > On Wed, Sep 21, 2022 at 12:06:38PM +0530, K Prateek Nayak wrote: > > > > Processors based on the Zen microarchitecture support IOPORT based deeper > > > > C-states. > > > > > > I've just gotta ask; why the heck are you using IO port based idle > > > states in 2022 ?!?! You have have MWAIT, right? > > > > They have both. And both is Intel technology. And as I'm sure you > > know AMD can't do their own thing - they kinda have to follow Intel. > > Unfortunately. > > > > Are you saying modern Intel chipsets don't do IO-based C-states anymore? > > I've no idea what they do, but Linux exclusively uses MWAIT on Intel as > per intel_idle.c. Well, it can be forced to use ACPI idle instead. > MWAIT also cuts down on IPIs because it wakes from the TIF write. Right.
