Commit 8cdc4940 authored by Mario Limonciello (AMD)'s avatar Mario Limonciello (AMD)
Browse files

cpufreq/amd-pstate: Cache the max frequency in cpudata 



The value of maximum frequency is fixed and never changes. Doing
calculations every time based off of perf is unnecessary.

Reviewed-by: default avatarGautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20260326193620.649441-1-mario.limonciello@amd.com


Signed-off-by: default avatarMario Limonciello (AMD) <superm1@kernel.org>
parent 88d2ca6a

drivers/cpufreq/amd-pstate.c

+9 −18
Original line number Diff line number Diff line
@@ -826,15 +826,13 @@ static void amd_pstate_adjust_perf(unsigned int cpu, 
static int amd_pstate_cpu_boost_update(struct cpufreq_policy *policy, bool on)

{

	struct amd_cpudata *cpudata = policy->driver_data;

	union perf_cached perf = READ_ONCE(cpudata->perf);

	u32 nominal_freq, max_freq;

	u32 nominal_freq;

	int ret = 0;



	nominal_freq = READ_ONCE(cpudata->nominal_freq);

	max_freq = perf_to_freq(perf, cpudata->nominal_freq, perf.highest_perf);



	if (on)

		policy->cpuinfo.max_freq = max_freq;

		policy->cpuinfo.max_freq = cpudata->max_freq;

	else if (policy->cpuinfo.max_freq > nominal_freq)

		policy->cpuinfo.max_freq = nominal_freq;
@@ -1021,13 +1019,15 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata) 


	WRITE_ONCE(cpudata->nominal_freq, nominal_freq);



	/* max_freq is calculated according to (nominal_freq * highest_perf)/nominal_perf */

	max_freq = perf_to_freq(perf, nominal_freq, perf.highest_perf);

	WRITE_ONCE(cpudata->max_freq, max_freq);



	lowest_nonlinear_freq = perf_to_freq(perf, nominal_freq, perf.lowest_nonlinear_perf);

	WRITE_ONCE(cpudata->lowest_nonlinear_freq, lowest_nonlinear_freq);



	/**

	 * Below values need to be initialized correctly, otherwise driver will fail to load

	 * max_freq is calculated according to (nominal_freq * highest_perf)/nominal_perf

	 * lowest_nonlinear_freq is a value between [min_freq, nominal_freq]

	 * Check _CPC in ACPI table objects if any values are incorrect

	 */
@@ -1090,9 +1090,7 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy) 
	policy->cpuinfo.min_freq = policy->min = perf_to_freq(perf,

							      cpudata->nominal_freq,

							      perf.lowest_perf);

	policy->cpuinfo.max_freq = policy->max = perf_to_freq(perf,

							      cpudata->nominal_freq,

							      perf.highest_perf);

	policy->cpuinfo.max_freq = policy->max = cpudata->max_freq;



	policy->driver_data = cpudata;

	ret = amd_pstate_cppc_enable(policy);
@@ -1167,14 +1165,9 @@ static void amd_pstate_cpu_exit(struct cpufreq_policy *policy) 
static ssize_t show_amd_pstate_max_freq(struct cpufreq_policy *policy,

					char *buf)

{

	struct amd_cpudata *cpudata;

	union perf_cached perf;



	cpudata = policy->driver_data;

	perf = READ_ONCE(cpudata->perf);

	struct amd_cpudata *cpudata = policy->driver_data;



	return sysfs_emit(buf, "%u\n",

			  perf_to_freq(perf, cpudata->nominal_freq, perf.highest_perf));

	return sysfs_emit(buf, "%u\n", cpudata->max_freq);

}



static ssize_t show_amd_pstate_lowest_nonlinear_freq(struct cpufreq_policy *policy,
@@ -1702,9 +1695,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) 
	policy->cpuinfo.min_freq = policy->min = perf_to_freq(perf,

							      cpudata->nominal_freq,

							      perf.lowest_perf);

	policy->cpuinfo.max_freq = policy->max = perf_to_freq(perf,

							      cpudata->nominal_freq,

							      perf.highest_perf);

	policy->cpuinfo.max_freq = policy->max = cpudata->max_freq;

	policy->driver_data = cpudata;



	ret = amd_pstate_cppc_enable(policy);

drivers/cpufreq/amd-pstate.h

+2 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ struct amd_aperf_mperf { 
 * @min_limit_freq: Cached value of policy->min (in khz)

 * @max_limit_freq: Cached value of policy->max (in khz)

 * @nominal_freq: the frequency (in khz) that mapped to nominal_perf

 * @max_freq: in ideal conditions the maximum frequency (in khz) possible frequency

 * @lowest_nonlinear_freq: the frequency (in khz) that mapped to lowest_nonlinear_perf

 * @floor_freq: Cached value of the user requested floor_freq

 * @cur: Difference of Aperf/Mperf/tsc count between last and current sample
@@ -103,6 +104,7 @@ struct amd_cpudata { 
	u32	min_limit_freq;

	u32	max_limit_freq;

	u32	nominal_freq;

	u32	max_freq;

	u32	lowest_nonlinear_freq;

	u32	floor_freq;