On Wed, Nov 25, 2020 at 02:45:37PM +0100, Peter Zijlstra wrote: > On Tue, Nov 17, 2020 at 06:20:01PM -0500, Joel Fernandes (Google) wrote: > > Some hardware such as certain AMD variants don't have cross-HT MDS/L1TF > > issues. Detect this and don't enable core scheduling as it can > > needlessly slow those device down. > > > > However, some users may want core scheduling even if the hardware is > > secure. To support them, add a coresched= option which defaults to > > 'secure' and can be overridden to 'on' if the user wants to enable > > coresched even if the HW is not vulnerable. 'off' would disable > > core scheduling in any case. > > This is all sorts of wrong, and the reason is because you hard-coded > that stupid policy. > > Core scheduling should always be available on SMT (provided you did that > CONFIG_ thing). Even on AMD systems RT tasks might want to claim the > core exclusively.
Agreed, specifically if we need to have special cgroup tag/association to enable it. Balbir Singh.
