Messages in this thread | | | Subject | Re: [PATCH] cpufreq: intel_pstate: Update EPP for AlderLake mobile | From | Artem Bityutskiy <> | Date | Wed, 29 Dec 2021 12:22:28 +0200 |
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On Thu, 2021-12-16 at 10:33 -0800, Srinivas Pandruvada wrote: > There is an expectation from users that they can get frequency specified > by cpufreq/cpuinfo_max_freq when conditions permit. But with AlderLake > mobile it may not be possible. This is possible that frequency is clipped > based on the system power-up EPP value. In this case users can update > cpufreq/energy_performance_preference to some performance oriented EPP to > limit clipping of frequencies. > > To get out of box behavior as the prior generations of CPUs, update EPP > for AlderLake mobile CPUs on boot. On prior generations of CPUs EPP = 128 > was enough to get maximum frequency, but with AlderLake mobile the > equivalent EPP is 102. Since EPP is model specific, this is possible that > they have different meaning on each generation of CPU. > > The current EPP string "balance_performance" corresponds to EPP = 128. > Change the EPP corresponding to "balance_performance" to 102 for only > AlderLake mobile CPUs and update this on each CPU during boot. > > To implement reuse epp_values[] array and update the modified EPP at the > index for BALANCE_PERFORMANCE. Add a dummy EPP_INDEX_DEFAULT to > epp_values[] to match indexes in the energy_perf_strings[]. > > After HWP PM is enabled also update EPP when "balance_performance" is > redefined for the very first time after the boot on each CPU. On > subsequent suspend/resume or offline/online the old EPP is restored, > so no specific action is needed. > > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
I think this patch alone makes things a bit inconsistent, because the 'x86_energy_perf_policy' does not get adjusted.
Ideally, constants like HWP_EPP_BALANCE_PERFORMANCE should go away from arch/x86/include/asm/msr-index.h, along with all users.
Artem.
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