diff mbox series

[v3,12/15] cpufreq/amd-pstate: Always write EPP value when updating perf

Message ID 20241209185248.16301-13-mario.limonciello@amd.com
State New
Headers show
Series amd-pstate fixes and improvements for 6.14 | expand

Commit Message

Mario Limonciello Dec. 9, 2024, 6:52 p.m. UTC
For MSR systems the EPP value is in the same register as perf targets
and so divding them into two separate MSR writes is wasteful.

In msr_update_perf(), update both EPP and perf values in one write to
MSR_AMD_CPPC_REQ, and cache them if successful.

To accomplish this plumb the EPP value into the update_perf call and
modify all its callers to check the return value.

As this unifies calls, ensure that the MSR write is necessary before
flushing a write out. Also drop the comparison from the passive flow
tracing.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v3:
 * Squash
   "Always write EPP value when updating perf"
   and
   "Check if CPPC request has changed before writing to the MSR or shared memory"
 * Remove extra write to cached value
 * Add comment explaining why updating two cached variables
---
 drivers/cpufreq/amd-pstate-trace.h |   7 +-
 drivers/cpufreq/amd-pstate.c       | 108 +++++++++++++++--------------
 2 files changed, 56 insertions(+), 59 deletions(-)
diff mbox series

Patch

diff --git a/drivers/cpufreq/amd-pstate-trace.h b/drivers/cpufreq/amd-pstate-trace.h
index e2221a4b6901c..8d692415d9050 100644
--- a/drivers/cpufreq/amd-pstate-trace.h
+++ b/drivers/cpufreq/amd-pstate-trace.h
@@ -32,7 +32,6 @@  TRACE_EVENT(amd_pstate_perf,
 		 u64 aperf,
 		 u64 tsc,
 		 unsigned int cpu_id,
-		 bool changed,
 		 bool fast_switch
 		 ),
 
@@ -44,7 +43,6 @@  TRACE_EVENT(amd_pstate_perf,
 		aperf,
 		tsc,
 		cpu_id,
-		changed,
 		fast_switch
 		),
 
@@ -57,7 +55,6 @@  TRACE_EVENT(amd_pstate_perf,
 		__field(unsigned long long, aperf)
 		__field(unsigned long long, tsc)
 		__field(unsigned int, cpu_id)
-		__field(bool, changed)
 		__field(bool, fast_switch)
 		),
 
@@ -70,11 +67,10 @@  TRACE_EVENT(amd_pstate_perf,
 		__entry->aperf = aperf;
 		__entry->tsc = tsc;
 		__entry->cpu_id = cpu_id;
-		__entry->changed = changed;
 		__entry->fast_switch = fast_switch;
 		),
 
-	TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u changed=%s fast_switch=%s",
+	TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u fast_switch=%s",
 		  (unsigned long)__entry->min_perf,
 		  (unsigned long)__entry->target_perf,
 		  (unsigned long)__entry->capacity,
@@ -83,7 +79,6 @@  TRACE_EVENT(amd_pstate_perf,
 		  (unsigned long long)__entry->aperf,
 		  (unsigned long long)__entry->tsc,
 		  (unsigned int)__entry->cpu_id,
-		  (__entry->changed) ? "true" : "false",
 		  (__entry->fast_switch) ? "true" : "false"
 		 )
 );
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index d21acd961edcd..fc0eb268c0335 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -222,25 +222,47 @@  static s16 shmem_get_epp(struct amd_cpudata *cpudata)
 }
 
 static int msr_update_perf(struct amd_cpudata *cpudata, u32 min_perf,
-			       u32 des_perf, u32 max_perf, bool fast_switch)
+			   u32 des_perf, u32 max_perf, u32 epp, bool fast_switch)
 {
+	u64 value, prev;
+
+	value = prev = READ_ONCE(cpudata->cppc_req_cached);
+
+	value &= ~(AMD_CPPC_MAX_PERF_MASK | AMD_CPPC_MIN_PERF_MASK |
+		   AMD_CPPC_DES_PERF_MASK | AMD_CPPC_EPP_PERF_MASK);
+	value |= FIELD_PREP(AMD_CPPC_MAX_PERF_MASK, max_perf);
+	value |= FIELD_PREP(AMD_CPPC_DES_PERF_MASK, des_perf);
+	value |= FIELD_PREP(AMD_CPPC_MIN_PERF_MASK, min_perf);
+	value |= FIELD_PREP(AMD_CPPC_EPP_PERF_MASK, epp);
+
+	if (value == prev)
+		return 0;
+
 	if (fast_switch) {
-		wrmsrl(MSR_AMD_CPPC_REQ, READ_ONCE(cpudata->cppc_req_cached));
+		wrmsrl(MSR_AMD_CPPC_REQ, value);
 		return 0;
+	} else {
+		int ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+
+		if (ret)
+			return ret;
 	}
 
-	return wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
-			     READ_ONCE(cpudata->cppc_req_cached));
+	WRITE_ONCE(cpudata->cppc_req_cached, value);
+	WRITE_ONCE(cpudata->epp_cached, epp);
+
+	return 0;
 }
 
 DEFINE_STATIC_CALL(amd_pstate_update_perf, msr_update_perf);
 
 static inline int amd_pstate_update_perf(struct amd_cpudata *cpudata,
 					  u32 min_perf, u32 des_perf,
-					  u32 max_perf, bool fast_switch)
+					  u32 max_perf, u32 epp,
+					  bool fast_switch)
 {
 	return static_call(amd_pstate_update_perf)(cpudata, min_perf, des_perf,
-						   max_perf, fast_switch);
+						   max_perf, epp, fast_switch);
 }
 
 static int msr_set_epp(struct amd_cpudata *cpudata, u32 epp)
@@ -261,6 +283,7 @@  static int msr_set_epp(struct amd_cpudata *cpudata, u32 epp)
 		return ret;
 	}
 
+	/* update both so that msr_update_perf() can effectively check */
 	WRITE_ONCE(cpudata->epp_cached, epp);
 	WRITE_ONCE(cpudata->cppc_req_cached, value);
 
@@ -459,12 +482,18 @@  static inline int amd_pstate_init_perf(struct amd_cpudata *cpudata)
 	return static_call(amd_pstate_init_perf)(cpudata);
 }
 
-static int shmem_update_perf(struct amd_cpudata *cpudata,
-			     u32 min_perf, u32 des_perf,
-			     u32 max_perf, bool fast_switch)
+static int shmem_update_perf(struct amd_cpudata *cpudata, u32 min_perf,
+			     u32 des_perf, u32 max_perf, u32 epp, bool fast_switch)
 {
 	struct cppc_perf_ctrls perf_ctrls;
 
+	if (cppc_state == AMD_PSTATE_ACTIVE) {
+		int ret = shmem_set_epp(cpudata, epp);
+
+		if (ret)
+			return ret;
+	}
+
 	perf_ctrls.max_perf = max_perf;
 	perf_ctrls.min_perf = min_perf;
 	perf_ctrls.desired_perf = des_perf;
@@ -510,9 +539,7 @@  static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
 {
 	unsigned long max_freq;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpudata->cpu);
-	u64 prev = READ_ONCE(cpudata->cppc_req_cached);
 	u32 nominal_perf = READ_ONCE(cpudata->nominal_perf);
-	u64 value = prev;
 
 	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
 
@@ -528,27 +555,14 @@  static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
 	if (!cpudata->boost_supported)
 		max_perf = min_t(unsigned long, nominal_perf, max_perf);
 
-	value &= ~(AMD_CPPC_MAX_PERF_MASK | AMD_CPPC_MIN_PERF_MASK |
-		   AMD_CPPC_DES_PERF_MASK);
-	value |= FIELD_PREP(AMD_CPPC_MAX_PERF_MASK, max_perf);
-	value |= FIELD_PREP(AMD_CPPC_DES_PERF_MASK, des_perf);
-	value |= FIELD_PREP(AMD_CPPC_MIN_PERF_MASK, min_perf);
-
 	if (trace_amd_pstate_perf_enabled() && amd_pstate_sample(cpudata)) {
 		trace_amd_pstate_perf(min_perf, des_perf, max_perf, cpudata->freq,
 			cpudata->cur.mperf, cpudata->cur.aperf, cpudata->cur.tsc,
-				cpudata->cpu, (value != prev), fast_switch);
+				cpudata->cpu, fast_switch);
 	}
 
-	if (value == prev)
-		goto cpufreq_policy_put;
+	amd_pstate_update_perf(cpudata, min_perf, des_perf, max_perf, 0, fast_switch);
 
-	WRITE_ONCE(cpudata->cppc_req_cached, value);
-
-	amd_pstate_update_perf(cpudata, min_perf, des_perf,
-			       max_perf, fast_switch);
-
-cpufreq_policy_put:
 	cpufreq_cpu_put(policy);
 }
 
@@ -1544,36 +1558,24 @@  static void amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
 static int amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
 {
 	struct amd_cpudata *cpudata = policy->driver_data;
-	u64 value;
+	u32 epp;
 
 	amd_pstate_update_min_max_limit(policy);
 
-	value = READ_ONCE(cpudata->cppc_req_cached);
-
-	value &= ~(AMD_CPPC_MAX_PERF_MASK | AMD_CPPC_MIN_PERF_MASK |
-		   AMD_CPPC_DES_PERF_MASK | AMD_CPPC_EPP_PERF_MASK);
-	value |= FIELD_PREP(AMD_CPPC_MAX_PERF_MASK, cpudata->max_limit_perf);
-	value |= FIELD_PREP(AMD_CPPC_DES_PERF_MASK, 0);
-	value |= FIELD_PREP(AMD_CPPC_MIN_PERF_MASK, cpudata->min_limit_perf);
-
 	if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
-		WRITE_ONCE(cpudata->epp_cached, 0);
-	value |= FIELD_PREP(AMD_CPPC_EPP_PERF_MASK, cpudata->epp_cached);
-
-	WRITE_ONCE(cpudata->cppc_req_cached, value);
+		epp = 0;
+	else
+		epp = READ_ONCE(cpudata->epp_cached);
 
 	if (trace_amd_pstate_epp_perf_enabled()) {
-		trace_amd_pstate_epp_perf(cpudata->cpu, cpudata->highest_perf,
-					  cpudata->epp_cached,
+		trace_amd_pstate_epp_perf(cpudata->cpu, cpudata->highest_perf, epp,
 					  cpudata->min_limit_perf,
 					  cpudata->max_limit_perf,
 					  policy->boost_enabled);
 	}
 
-	amd_pstate_update_perf(cpudata, cpudata->min_limit_perf, 0U,
-			       cpudata->max_limit_perf, false);
-
-	return amd_pstate_set_epp(cpudata, READ_ONCE(cpudata->epp_cached));
+	return amd_pstate_update_perf(cpudata, cpudata->min_limit_perf, 0U,
+				      cpudata->max_limit_perf, epp, false);
 }
 
 static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
@@ -1602,7 +1604,7 @@  static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
 	return 0;
 }
 
-static void amd_pstate_epp_reenable(struct amd_cpudata *cpudata)
+static int amd_pstate_epp_reenable(struct amd_cpudata *cpudata)
 {
 	u64 max_perf;
 	int ret;
@@ -1620,17 +1622,19 @@  static void amd_pstate_epp_reenable(struct amd_cpudata *cpudata)
 					  max_perf, cpudata->boost_state);
 	}
 
-	amd_pstate_update_perf(cpudata, 0, 0, max_perf, false);
-	amd_pstate_set_epp(cpudata, cpudata->epp_cached);
+	return amd_pstate_update_perf(cpudata, 0, 0, max_perf, cpudata->epp_cached, false);
 }
 
 static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy)
 {
 	struct amd_cpudata *cpudata = policy->driver_data;
+	int ret;
 
 	pr_debug("AMD CPU Core %d going online\n", cpudata->cpu);
 
-	amd_pstate_epp_reenable(cpudata);
+	ret = amd_pstate_epp_reenable(cpudata);
+	if (ret)
+		return ret;
 	cpudata->suspended = false;
 
 	return 0;
@@ -1654,10 +1658,8 @@  static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
 					  min_perf, min_perf, policy->boost_enabled);
 	}
 
-	amd_pstate_update_perf(cpudata, min_perf, 0, min_perf, false);
-	amd_pstate_set_epp(cpudata, AMD_CPPC_EPP_BALANCE_POWERSAVE);
-
-	return 0;
+	return amd_pstate_update_perf(cpudata, min_perf, 0, min_perf,
+				      AMD_CPPC_EPP_BALANCE_POWERSAVE, false);
 }
 
 static int amd_pstate_epp_suspend(struct cpufreq_policy *policy)