[PATCH] cpufreq: intel_pstate: Drop redundant intel_pstate_get_hwp_cap() call

Rafael J. Wysocki
2021-12-10T16:12:22Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It is not necessary to call intel_pstate_get_hwp_cap() from
intel_pstate_update_perf_limits(), because it gets called from
intel_pstate_verify_cpu_policy() which is either invoked directly
right before intel_pstate_update_perf_limits(), in
intel_cpufreq_verify_policy() in the passive mode, or called
from driver callbacks in a sequence that causes it to be followed
by an immediate intel_pstate_update_perf_limits().

Namely, in the active mode intel_cpufreq_verify_policy() is called
by intel_pstate_verify_policy() which is the ->verify() callback
routine of intel_pstate and gets called by the cpufreq core right
before intel_pstate_set_policy(), which is the driver's ->setoplicy()
callback routine, where intel_pstate_update_perf_limits() is called.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/intel_pstate.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)

Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -2486,18 +2486,14 @@ static void intel_pstate_update_perf_lim
* HWP needs some special consideration, because HWP_REQUEST uses
* abstract values to represent performance rather than pure ratios.
*/
- if (hwp_active) {
- intel_pstate_get_hwp_cap(cpu);
+ if (hwp_active && cpu->pstate.scaling != perf_ctl_scaling) {
+ int scaling = cpu->pstate.scaling;
+ int freq;

- if (cpu->pstate.scaling != perf_ctl_scaling) {
- int scaling = cpu->pstate.scaling;
- int freq;
-
- freq = max_policy_perf * perf_ctl_scaling;
- max_policy_perf = DIV_ROUND_UP(freq, scaling);
- freq = min_policy_perf * perf_ctl_scaling;
- min_policy_perf = DIV_ROUND_UP(freq, scaling);
- }
+ freq = max_policy_perf * perf_ctl_scaling;
+ max_policy_perf = DIV_ROUND_UP(freq, scaling);
+ freq = min_policy_perf * perf_ctl_scaling;
+ min_policy_perf = DIV_ROUND_UP(freq, scaling);
}

pr_debug("cpu:%d min_policy_perf:%d max_policy_perf:%d\n",