kernel/drivers/cpufreq/intel_pstate.c, branch linux-6.9.y

cpufreq: intel_pstate: Use HWP to initialize ITMT if CPPC is missing

2024-07-05T07:38:12Z

commit a1ff59784b277795a613beaa5d3dd9c5595c69a7 upstream. It is reported that single-thread performance on some hybrid systems dropped significantly after commit 7feec7430edd ("ACPI: CPPC: Only probe for _CPC if CPPC v2 is acked") which prevented _CPC from being used if the support for it had not been confirmed by the platform firmware. The problem is that if the platform firmware does not confirm CPPC v2 support, cppc_get_perf_caps() returns an error which prevents the intel_pstate driver from enabling ITMT. Consequently, the scheduler does not get any hints on CPU performance differences, so in a hybrid system some tasks may run on CPUs with lower capacity even though they should be running on high-capacity CPUs. To address this, modify intel_pstate to use the information from MSR_HWP_CAPABILITIES to enable ITMT if CPPC is not available (which is done already if the highest performance number coming from CPPC is not realistic). Fixes: 7feec7430edd ("ACPI: CPPC: Only probe for _CPC if CPPC v2 is acked") Closes: https://lore.kernel.org/linux-acpi/d01b0a1f-bd33-47fe-ab41-43843d8a374f@kfocus.org Link: https://lore.kernel.org/linux-acpi/ZnD22b3Br1ng7alf@kf-XE Reported-by: Aaron Rainbolt Tested-by: Aaron Rainbolt Cc: 5.19+ # 5.19+ Link: https://patch.msgid.link/12460110.O9o76ZdvQC@rjwysocki.net Signed-off-by: Rafael J. Wysocki Reviewed-by: Mario Limonciello Signed-off-by: Greg Kroah-Hartman

Merge back cpufreq material for 6.9-rc1.

2024-03-11T14:08:45Z

cpufreq: intel_pstate: Update default EPPs for Meteor Lake

2024-02-24T14:02:33Z

Update default balanced_performance EPP to 115 and performance EPP to 16. Changing the balanced_performance EPP has better performance/watt compared to default powerup EPP value of 128. Changing the performance EPP to 0x10 shows reduced power for similar performance as EPP 0. On small form factor devices this is beneficial as lower power results in lower CPU and skin temperature. This results in reduced thermal throttling and higher performance. Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Allow model specific EPPs

2024-02-24T14:02:33Z

The current implementation allows model specific EPP override for balanced_performance. Add feature to allow model specific EPP for all predefined EPP strings. For example for some CPU models, even changing performance EPP has benefits Use a mask of EPPs as driver_data instead of just balanced_performance. Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: fix pstate limits enforcement for adjust_perf call back

2024-02-24T14:01:59Z

There is a loophole in pstate limit clamping for the intel_cpufreq CPU frequency scaling driver (intel_pstate in passive mode), schedutil CPU frequency scaling governor, HWP (HardWare Pstate) control enabled, when the adjust_perf call back path is used. Fix it. Fixes: a365ab6b9dfb cpufreq: intel_pstate: Implement the ->adjust_perf() callback Signed-off-by: Doug Smythies Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: remove cpudata::prev_cummulative_iowait

2024-02-13T12:47:35Z

Commit 09c448d3c61f ("cpufreq: intel_pstate: Use IOWAIT flag in Atom algorithm") removed the last user of cpudata::prev_cummulative_iowait. Remove the member too. Found by https://github.com/jirislaby/clang-struct. Signed-off-by: Jiri Slaby (SUSE) Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Refine computation of P-state for given frequency

2024-01-22T14:18:11Z

On systems using HWP, if a given frequency is equal to the maximum turbo frequency or the maximum non-turbo frequency, the HWP performance level corresponding to it is already known and can be used directly without any computation. Accordingly, adjust the code to use the known HWP performance levels in the cases mentioned above. This also helps to avoid limiting CPU capacity artificially in some cases when the BIOS produces the HWP_CAP numbers using a different E-core-to-P-core performance scaling factor than expected by the kernel. Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores") Cc: 6.1+ # 6.1+ Tested-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Update hybrid scaling factor for Meteor Lake

2024-01-10T14:02:25Z

On some Meteor Lake platforms, maximum one core turbo frequency is not observed. During hybrid performance to frequency conversion, the maximum frequency is 100 MHz less. This results in requesting maximum frequency 100 MHz less. For example when the max one core turbo is 4.9 GHz: MSR HWP_CAPABILITIES shows highest performance ratio for P-core is 0x3E. With the current scaling factor of 78741 (1.27x for converting frequency to performance) results in max frequency of 4.8 GHz. This results in capping the max scaling frequency as 4.8 GHz, which is 100 MHz less than the desired. Add capability to define per CPU model specific scaling factor and define scaling factor of 80000 (1.25x for converting frequency to performance for P-cores) for Meteor Lake. Signed-off-by: Srinivas Pandruvada [ rjw: Debug message adjustment, subject edit ] Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Add Emerald Rapids support in no-HWP mode

2023-12-19T20:38:09Z

Users may disable HWP in firmware, in which case intel_pstate will give up unless the CPU model is explicitly supported. See also the following past commits: - commit df51f287b5de ("cpufreq: intel_pstate: Add Sapphire Rapids support in no-HWP mode") - commit d8de7a44e11f ("cpufreq: intel_pstate: Add Skylake servers support") - commit 706c5328851d ("cpufreq: intel_pstate: Add Cometlake support in no-HWP mode") - commit fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode") - commit 71bb5c82aaae ("cpufreq: intel_pstate: Add Tigerlake support in no-HWP mode") Signed-off-by: Zhenguo Yao Acked-by: Srinivas Pandruvada [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki

cpufreq: intel_pstate: Prioritize firmware-provided balance performance EPP

2023-12-05T20:29:47Z

The platform firmware can provide a balance performance EPP value by enabling HWP and programming the EPP to the desired value. However, currently this only takes effect for processors listed in intel_epp_balance_perf[], so in order to enable a new processor model to utilize this mechanism, that table needs to be updated. It arguably should not be necessary to modify the kernel to work properly with every new generation of processors, though, and distributions that don't always ship the most recent kernels should be able to run reasonably well on new hardware without code changes. For this reason, move the check to avoid updating the EPP when the balance performance EPP is unmodified from the power-up default of 0x80 after the check that allows the firmware-provided balance performance EPP value to be retrieved. This will cause the code to always look for the firmware- provided value before consulting intel_epp_balance_perf[] and the handling of new hardware will not depend on whether or not that thable has been updated yet. Signed-off-by: Srinivas Pandruvada [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki