On 15/01/2020 11:32, Jan Beulich wrote: > On 14.01.2020 20:36, Igor Druzhinin wrote: >> If ITSC is not available on CPU (e.g if running nested as PV shim) >> then X86_FEATURE_NONSTOP_TSC is not advertised in certain cases, i.e. >> all AMD and some old Intel processors. In which case TSC would need to >> be restored on CPU from platform time by Xen upon exiting deep C-states. > > How does waking from deep C states correspond to the PV shim? I notice > that cstate_restore_tsc() gets called irrespective of the C state being > exited, so I wonder whether there's room for improvement there > independent of the issue at hand. As far as this change is concerned, > I think you want to drop the notion of "deep" from the description.
I'm not familiar with what to call "deep C-state" so for me it was anything higher than C1. If you prefer "deep" to be dropped - so be it. Igor _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
