Hello, I currently have a very simple application (no RTOS) running on a single-core x86 inmate that is unaware of P-states. I am also running with Hardware P-states (HWP) disabled on the Linux command line. When the root cell gives control of the core over to the inmate, it's unclear to me what happens to the P-state of that core. If it has an idle P-state, and then is handed off to inmate, will it still be at the same P-state? Or will it get reset to the full-throttle P0 P-state?
In my testing, my inmate appears to be running full throttle at the base frequency, meaning that the P-state gets reset to P0 somehow. But I'm not sure how to verify this beyond calculating the frequency with aperf and mperf, which I'm doing. I guess I could dive into the Linux source code to see what the intel_pstate driver is doing, but I am a bit nervous that I might not understand it. So I'm hoping someone here knows how this handoff works. Maybe there is some kind of watchdog timer that needs to be actively reset by the intel_pstate driver to keep a core at a P-state other than P0. Thanks, Michael -- You received this message because you are subscribed to the Google Groups "Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jailhouse-dev/5cd0fb26-8c4f-482c-9ac9-6f6b1d234f03%40googlegroups.com.
