linux-kernel - [PATCH 05/15] cpufreq/amd-pstate: Store the boost numerator as highest perf again

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Message-ID: <20241205222847.7889-6-mario.limonciello@amd.com>
Date: Thu, 5 Dec 2024 16:28:37 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: "Gautham R . Shenoy" <gautham.shenoy@....com>
CC: Perry Yuan <perry.yuan@....com>, <linux-kernel@...r.kernel.org>,
	<linux-pm@...r.kernel.org>, Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
	Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH 05/15] cpufreq/amd-pstate: Store the boost numerator as highest perf again

commit ad4caad58d91d ("cpufreq: amd-pstate: Merge
amd_pstate_highest_perf_set() into amd_get_boost_ratio_numerator()")
changed the semantics for highest perf and commit 18d9b52271213
("cpufreq/amd-pstate: Use nominal perf for limits when boost is disabled")
worked around those semantic changes.

This however is a confusing result and furthermore makes it awkward to
change frequency limits and boost due to the scaling differences. Restore
the boost numerator to highest perf again.

Suggested-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Fixes: ad4caad58d91 ("cpufreq: amd-pstate: Merge amd_pstate_highest_perf_set() into amd_get_boost_ratio_numerator()")
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 Documentation/admin-guide/pm/amd-pstate.rst |  4 +---
 drivers/cpufreq/amd-pstate.c                | 25 ++++++++++++---------
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 210a808b74ec2..412423c54f258 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -251,9 +251,7 @@ performance supported in `AMD CPPC Performance Capability <perf_cap_>`_).
 In some ASICs, the highest CPPC performance is not the one in the ``_CPC``
 table, so we need to expose it to sysfs. If boost is not active, but
 still supported, this maximum frequency will be larger than the one in
-``cpuinfo``. On systems that support preferred core, the driver will have
-different values for some cores than others and this will reflect the values
-advertised by the platform at bootup.
+``cpuinfo``.
 This attribute is read-only.
 
 ``amd_pstate_lowest_nonlinear_freq``
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index dbe014f3c2beb..738f63d70546f 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -408,15 +408,19 @@ static inline int amd_pstate_cppc_enable(bool enable)
 
 static int msr_init_perf(struct amd_cpudata *cpudata)
 {
-	u64 cap1;
+	u64 cap1, numerator;
 
 	int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
 				     &cap1);
 	if (ret)
 		return ret;
 
-	WRITE_ONCE(cpudata->highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
-	WRITE_ONCE(cpudata->max_limit_perf, AMD_CPPC_HIGHEST_PERF(cap1));
+	ret = amd_get_boost_ratio_numerator(cpudata->cpu, &numerator);
+	if (ret)
+		return ret;
+
+	WRITE_ONCE(cpudata->highest_perf, numerator);
+	WRITE_ONCE(cpudata->max_limit_perf, numerator);
 	WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
 	WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1));
@@ -428,13 +432,18 @@ static int msr_init_perf(struct amd_cpudata *cpudata)
 static int shmem_init_perf(struct amd_cpudata *cpudata)
 {
 	struct cppc_perf_caps cppc_perf;
+	u64 numerator;
 
 	int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
 	if (ret)
 		return ret;
 
-	WRITE_ONCE(cpudata->highest_perf, cppc_perf.highest_perf);
-	WRITE_ONCE(cpudata->max_limit_perf, cppc_perf.highest_perf);
+	ret = amd_get_boost_ratio_numerator(cpudata->cpu, &numerator);
+	if (ret)
+		return ret;
+
+	WRITE_ONCE(cpudata->highest_perf, numerator);
+	WRITE_ONCE(cpudata->max_limit_perf, numerator);
 	WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf,
 		   cppc_perf.lowest_nonlinear_perf);
@@ -920,7 +929,6 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
 {
 	int ret;
 	u32 min_freq, max_freq;
-	u64 numerator;
 	u32 nominal_perf, nominal_freq;
 	u32 lowest_nonlinear_perf, lowest_nonlinear_freq;
 	u32 boost_ratio, lowest_nonlinear_ratio;
@@ -942,10 +950,7 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
 
 	nominal_perf = READ_ONCE(cpudata->nominal_perf);
 
-	ret = amd_get_boost_ratio_numerator(cpudata->cpu, &numerator);
-	if (ret)
-		return ret;
-	boost_ratio = div_u64(numerator << SCHED_CAPACITY_SHIFT, nominal_perf);
+	boost_ratio = div_u64(cpudata->highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf);
 	max_freq = (nominal_freq * boost_ratio >> SCHED_CAPACITY_SHIFT) * 1000;
 
 	lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
-- 
2.43.0