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[v13,3/9] cpufreq: introduce init_boost callback to initialize boost state for pstate drivers

Message ID fef324b46625e5a9985b0c0c1bcfc05067d40e36.1718988436.git.perry.yuan@amd.com
State New
Headers show
Series AMD Pstate Driver Core Performance Boost | expand

Commit Message

Yuan, Perry June 21, 2024, 4:50 p.m. UTC
Introduce a new init_boost callback in cpufreq to initialize the boost
state for specific pstate drivers. This initialization is required before
calling the set_boost interface for each CPU.

The init_boost callback will set up and synchronize each CPU's current
boost state before invoking the set_boost function. Without this step,
the boost state may be inconsistent across CPUs.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 drivers/cpufreq/cpufreq.c | 14 ++++++++++++--
 include/linux/cpufreq.h   |  2 ++
 2 files changed, 14 insertions(+), 2 deletions(-)

Comments

Mario Limonciello June 24, 2024, 9:47 p.m. UTC | #1
On 6/21/2024 11:50, Perry Yuan wrote:
> Introduce a new init_boost callback in cpufreq to initialize the boost
> state for specific pstate drivers. This initialization is required before
> calling the set_boost interface for each CPU.
> 
> The init_boost callback will set up and synchronize each CPU's current
> boost state before invoking the set_boost function. Without this step,
> the boost state may be inconsistent across CPUs.
> 
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>

As a part of the testing on the v13 series the past few days, we 
realized that this patch is not necessary.  It's really a workaround for 
a change in behavior introduced in

f37a4d6b4a2c ("cpufreq: Fix per-policy boost behavior on SoCs using 
cpufreq_boost_set_sw()")

I've adjusted the series (as v14) to drop this patch and instead send a 
fix for that one.

> ---
>   drivers/cpufreq/cpufreq.c | 14 ++++++++++++--
>   include/linux/cpufreq.h   |  2 ++
>   2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 1fdabb660231..0c99d2dfdb53 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1429,8 +1429,18 @@ static int cpufreq_online(unsigned int cpu)
>   			goto out_free_policy;
>   		}
>   
> -		/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
> -		policy->boost_enabled = cpufreq_boost_enabled() && policy_has_boost_freq(policy);
> +		/* init boost state to prepare set_boost callback for each CPU */
> +		if (cpufreq_driver->init_boost) {
> +			ret = cpufreq_driver->init_boost(policy);
> +			if (ret) {
> +				pr_debug("%s: %d: boost initialization failed\n", __func__,
> +					__LINE__);
> +				goto out_offline_policy;
> +			}
> +		} else {
> +			/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
> +			policy->boost_enabled = cpufreq_boost_enabled() && policy_has_boost_freq(policy);
> +		}
>   
>   		/*
>   		 * The initialization has succeeded and the policy is online.
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index 20f7e98ee8af..0698c0292d8f 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -409,6 +409,8 @@ struct cpufreq_driver {
>   	bool		boost_enabled;
>   	int		(*set_boost)(struct cpufreq_policy *policy, int state);
>   
> +	/* initialize boost state to be consistent before calling set_boost */
> +	int		(*init_boost)(struct cpufreq_policy *policy);
>   	/*
>   	 * Set by drivers that want to register with the energy model after the
>   	 * policy is properly initialized, but before the governor is started.
diff mbox series

Patch

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 1fdabb660231..0c99d2dfdb53 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1429,8 +1429,18 @@  static int cpufreq_online(unsigned int cpu)
 			goto out_free_policy;
 		}
 
-		/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
-		policy->boost_enabled = cpufreq_boost_enabled() && policy_has_boost_freq(policy);
+		/* init boost state to prepare set_boost callback for each CPU */
+		if (cpufreq_driver->init_boost) {
+			ret = cpufreq_driver->init_boost(policy);
+			if (ret) {
+				pr_debug("%s: %d: boost initialization failed\n", __func__,
+					__LINE__);
+				goto out_offline_policy;
+			}
+		} else {
+			/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
+			policy->boost_enabled = cpufreq_boost_enabled() && policy_has_boost_freq(policy);
+		}
 
 		/*
 		 * The initialization has succeeded and the policy is online.
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 20f7e98ee8af..0698c0292d8f 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -409,6 +409,8 @@  struct cpufreq_driver {
 	bool		boost_enabled;
 	int		(*set_boost)(struct cpufreq_policy *policy, int state);
 
+	/* initialize boost state to be consistent before calling set_boost */
+	int		(*init_boost)(struct cpufreq_policy *policy);
 	/*
 	 * Set by drivers that want to register with the energy model after the
 	 * policy is properly initialized, but before the governor is started.