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From: Wyes Karny <wyes.karny@amd.com>
To: Rafael J Wysocki <rafael@kernel.org>,
	Huang Rui <ray.huang@amd.com>, Jonathan Corbet <corbet@lwn.net>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	<Mario.Limonciello@amd.com>, <Perry.Yuan@amd.com>,
	Ananth Narayan <ananth.narayan@amd.com>, <gautham.shenoy@amd.com>
Cc: <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-pm@vger.kernel.org>, Bagas Sanjaya <bagasdotme@gmail.com>,
	<santosh.shukla@amd.com>, Len Brown <lenb@kernel.org>,
	Robert Moore <robert.moore@intel.com>,
	Borislav Petkov <bp@suse.de>, Wyes Karny <wyes.karny@amd.com>
Subject: [PATCH v3 3/6] cpufreq: amd_pstate: Add guided autonomous mode
Date: Thu, 19 Jan 2023 11:50:14 +0000	[thread overview]
Message-ID: <20230119115017.10188-4-wyes.karny@amd.com> (raw)
In-Reply-To: <20230119115017.10188-1-wyes.karny@amd.com>

From ACPI spec below 3 modes for CPPC can be defined:
1. Non autonomous: OS scaling governor specifies operating frequency/
   performance level through `Desired Performance` register and platform
follows that.
2. Guided autonomous: OS scaling governor specifies min and max
   frequencies/ performance levels through `Minimum Performance` and
`Maximum Performance` register, and platform can autonomously select an
operating frequency in this range.
3. Fully autonomous: OS only hints (via EPP) to platform for the required
   energy performance preference for the workload and platform autonomously
scales the frequency.

Currently (1) is supported by amd_pstate as passive mode, and (3) is
implemented by EPP support. This change is to support (2).

In guided autonomous mode the min_perf is based on the input from the
scaling governor. For example, in case of schedutil this value depends
on the current utilization. And max_perf is set to max capacity.

To activate guided auto mode ``amd_pstate=guided`` command line
parameter has to be passed in the kernel.

Signed-off-by: Wyes Karny <wyes.karny@amd.com>
---
 .../admin-guide/kernel-parameters.txt         | 15 +++++---
 drivers/cpufreq/amd-pstate.c                  | 34 +++++++++++++++----
 include/linux/amd-pstate.h                    |  2 ++
 3 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index e3618dfdb36a..0d8486325c9a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7015,11 +7015,11 @@
 			  Do not enable amd_pstate as the default
 			  scaling driver for the supported processors
 			passive
-			  Use amd_pstate as a scaling driver, driver requests a
-			  desired performance on this abstract scale and the power
-			  management firmware translates the requests into actual
-			  hardware states (core frequency, data fabric and memory
-			  clocks etc.)
+			  Use amd_pstate with passive mode as a scaling driver.
+			  In this mode autonomous selection is disabled.
+			  Driver requests a desired performance level and platform
+			  tires to match the same performance level (if it is
+			  satisfied by guaranteed performance level).
 			active
 			  Use amd_pstate_epp driver instance as the scaling driver,
 			  driver provides a hint to the hardware if software wants
@@ -7027,3 +7027,8 @@
 			  to the CPPC firmware. then CPPC power algorithm will
 			  calculate the runtime workload and adjust the realtime cores
 			  frequency.
+			guided
+			  Activate guided autonomous mode. Driver requests minimum and
+			  maximum performance level and the platform autonomously
+			  selects a performance level in this range and appropriate
+			  to the current workload.
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index c5731fefcbef..6736ad260485 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -267,7 +267,22 @@ static int cppc_init_perf(struct amd_cpudata *cpudata)
 		   cppc_perf.lowest_nonlinear_perf);
 	WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf);
 
-	return 0;
+	if (cppc_state == AMD_PSTATE_ACTIVE)
+		return 0;
+
+	ret = cppc_get_auto_sel_caps(cpudata->cpu, &cppc_perf);
+	if (ret) {
+		pr_warn("failed to get auto_sel, ret: %d\n", ret);
+		return 0;
+	}
+
+	ret = cppc_set_auto_sel(cpudata->cpu,
+			(cppc_state == AMD_PSTATE_PASSIVE) ? 0 : 1);
+
+	if (ret)
+		pr_warn("failed to set auto_sel, ret: %d\n", ret);
+
+	return ret;
 }
 
 DEFINE_STATIC_CALL(amd_pstate_init_perf, pstate_init_perf);
@@ -344,12 +359,18 @@ static inline bool amd_pstate_sample(struct amd_cpudata *cpudata)
 }
 
 static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
-			      u32 des_perf, u32 max_perf, bool fast_switch)
+			      u32 des_perf, u32 max_perf, bool fast_switch, int guv_flags)
 {
 	u64 prev = READ_ONCE(cpudata->cppc_req_cached);
 	u64 value = prev;
 
 	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
+
+	if ((cppc_state == AMD_PSTATE_GUIDED) && (guv_flags & CPUFREQ_GOV_DYNAMIC_SWITCHING)) {
+		min_perf = des_perf;
+		des_perf = 0;
+	}
+
 	value &= ~AMD_CPPC_MIN_PERF(~0L);
 	value |= AMD_CPPC_MIN_PERF(min_perf);
 
@@ -404,7 +425,7 @@ static int amd_pstate_target(struct cpufreq_policy *policy,
 
 	cpufreq_freq_transition_begin(policy, &freqs);
 	amd_pstate_update(cpudata, min_perf, des_perf,
-			  max_perf, false);
+			  max_perf, false, policy->governor->flags);
 	cpufreq_freq_transition_end(policy, &freqs, false);
 
 	return 0;
@@ -438,7 +459,8 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 	if (max_perf < min_perf)
 		max_perf = min_perf;
 
-	amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true);
+	amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true,
+			policy->governor->flags);
 	cpufreq_cpu_put(policy);
 }
 
@@ -1238,7 +1260,7 @@ static int __init amd_pstate_init(void)
 	/* capability check */
 	if (boot_cpu_has(X86_FEATURE_CPPC)) {
 		pr_debug("AMD CPPC MSR based functionality is supported\n");
-		if (cppc_state == AMD_PSTATE_PASSIVE)
+		if (cppc_state != AMD_PSTATE_ACTIVE)
 			current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
 	} else {
 		pr_debug("AMD CPPC shared memory based functionality is supported\n");
@@ -1300,7 +1322,7 @@ static int __init amd_pstate_param(char *str)
 		if (cppc_state == AMD_PSTATE_ACTIVE)
 			current_pstate_driver = &amd_pstate_epp_driver;
 
-		if (cppc_state == AMD_PSTATE_PASSIVE)
+		if (cppc_state == AMD_PSTATE_PASSIVE || cppc_state == AMD_PSTATE_GUIDED)
 			current_pstate_driver = &amd_pstate_driver;
 
 		return 0;
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index e9e291b7c2f9..85e980b8e0ac 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -92,6 +92,7 @@ enum amd_pstate_mode {
 	AMD_PSTATE_DISABLE = 0,
 	AMD_PSTATE_PASSIVE,
 	AMD_PSTATE_ACTIVE,
+	AMD_PSTATE_GUIDED,
 	AMD_PSTATE_MAX,
 };
 
@@ -99,6 +100,7 @@ static const char * const amd_pstate_mode_string[] = {
 	[AMD_PSTATE_DISABLE]     = "disable",
 	[AMD_PSTATE_PASSIVE]     = "passive",
 	[AMD_PSTATE_ACTIVE]      = "active",
+	[AMD_PSTATE_GUIDED]      = "guided",
 	NULL,
 };
 
-- 
2.34.1


  parent reply	other threads:[~2023-01-19 11:52 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-19 11:50 [PATCH v3 0/6] amd_pstate: Add guided autonomous mode support Wyes Karny
2023-01-19 11:50 ` [PATCH v3 1/6] acpi: cppc: Add min and max perf reg writing support Wyes Karny
2023-01-19 11:50 ` [PATCH v3 2/6] acpi: cppc: Add auto select register read/write support Wyes Karny
2023-01-19 11:50 ` Wyes Karny [this message]
2023-01-19 11:50 ` [PATCH v3 4/6] Documentation: amd_pstate: Move amd_pstate param to alphabetical order Wyes Karny
2023-01-19 11:50 ` [PATCH v3 5/6] cpufreq: amd_pstate: Add guided mode control support via sysfs Wyes Karny
2023-01-19 11:50 ` [PATCH v3 6/6] Documentation: amd_pstate: Update amd_pstate status sysfs for guided Wyes Karny
2023-01-19 12:30   ` Bagas Sanjaya
2023-01-20  4:16     ` Wyes Karny
2023-01-20  9:18 ` [PATCH v3 0/6] amd_pstate: Add guided autonomous mode support Huang Rui
2023-01-20  9:55   ` Wyes Karny
2023-01-24 20:40 ` Tor Vic
2023-01-25 10:25   ` Wyes Karny
2023-01-31  5:34   ` Wyes Karny
2023-02-01 18:15     ` Tor Vic

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