On 08.07.2025 06:02, Penny, Zheng wrote: >> -----Original Message----- >> From: Jan Beulich <jbeul...@suse.com> >> Sent: Tuesday, June 17, 2025 6:38 PM >> >> On 27.05.2025 10:48, Penny Zheng wrote: >>> --- a/tools/misc/xenpm.c >>> +++ b/tools/misc/xenpm.c >>> + >>> + case XEN_SYSCTL_CPPC_SET_PRESET_BALANCE: >>> + if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED ) >>> + return -EINVAL; >>> + policy->policy = CPUFREQ_POLICY_BALANCE; >>> + min_perf = data->caps.lowest_perf; >>> + max_perf = data->caps.highest_perf; >>> + epp = CPPC_ENERGY_PERF_BALANCE; >>> + break; >> >> Isn't this more line "ondemand"? To me, "balance" would mean tying perf to >> at least >> close around the middle of lowest and highest. > > The "balance" word comes from the epp value, it is 127, which is the middle > value > In actual hardware algorithm, the value of Energy Performance Preference > register(EPP) will be translated to frequency setting, > And it sets the minimum active frequency. > An EPP of zero sets the min active frequency to Fmax, while an EPP of 255 > sets the min active frequency to Fmin (~IdleFreq). It is linear scaling, so > epp of 127 is calculated to the middle of Fmax and Fmin. > And Fmax corresponds to the highest perf, and Fmin corresponds to the > non-linear lowest perf
I'm fine with the EPP value picked here. My question - as to the min_perf and max_perf values that you set - remains, though. Jan
