Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [PATCH] cpufreq: intel_pstate: Use HWP capabilities in intel_cpufreq_adjust_perf() | Date | Tue, 05 Jan 2021 19:20:29 +0100 |
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If turbo P-states cannot be used, either due to the configuration of the processor, or because intel_pstate is not allowed to used them, the maximum available P-state with HWP enabled corresponds to the HWP_CAP.GUARANTEED value which is not static. It can be adjusted by an out-of-band agent or during an Intel Speed Select performance level change, so long as it remains less than or equal to HWP_CAP.MAX.
However, if turbo P-states cannot be used, intel_cpufreq_adjust_perf() always uses pstate.max_pstate (set during the initialization of the driver only) as the maximum available P-state, so it may miss a change of the HWP_CAP.GUARANTEED value.
Prevent that from happening by modifyig intel_cpufreq_adjust_perf() to always read the "guaranteed" and "maximum turbo" performance levels from the cached HWP_CAP value.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> --- drivers/cpufreq/intel_pstate.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -2653,12 +2653,13 @@ static void intel_cpufreq_adjust_perf(un unsigned long capacity) { struct cpudata *cpu = all_cpu_data[cpunum]; + u64 hwp_cap = READ_ONCE(cpu->hwp_cap_cached); int old_pstate = cpu->pstate.current_pstate; int cap_pstate, min_pstate, max_pstate, target_pstate; update_turbo_state(); - cap_pstate = global.turbo_disabled ? cpu->pstate.max_pstate : - cpu->pstate.turbo_pstate; + cap_pstate = global.turbo_disabled ? HWP_GUARANTEED_PERF(hwp_cap) : + HWP_HIGHEST_PERF(hwp_cap); /* Optimization: Avoid unnecessary divisions. */
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