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From: Beata Michalska <beata.michalska@arm.com>
To: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com,
	vanshikonda@os.amperecomputing.com
Cc: sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com,
	vincent.guittot@linaro.org, sumitg@nvidia.com,
	yang@os.amperecomputing.com, lihuisong@huawei.com,
	viresh.kumar@linaro.org
Subject: [PATCH v5 5/5] cpufreq: Use arch specific feedback for cpuinfo_cur_freq
Date: Wed, 17 Apr 2024 10:38:48 +0100	[thread overview]
Message-ID: <20240417093848.1555462-6-beata.michalska@arm.com> (raw)
In-Reply-To: <20240417093848.1555462-1-beata.michalska@arm.com>

Some architectures provide a way to determine an average frequency over
a certain period of time based on available performance monitors (AMU on
ARM or APERF/MPERf on x86). With those at hand, enroll arch_freq_get_on_cpu
into cpuinfo_cur_freq policy sysfs attribute handler, which is expected to
represent the current frequency of a given CPU,as obtained by the hardware.
This is the type of feedback that counters do provide.

Signed-off-by: Beata Michalska <beata.michalska@arm.com>
---
 drivers/cpufreq/cpufreq.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index f6f8d7f450e7..89118406ec68 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -793,8 +793,10 @@ store_one(scaling_max_freq, max);
 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
 					char *buf)
 {
-	unsigned int cur_freq = __cpufreq_get(policy);
+	unsigned int cur_freq = arch_freq_get_on_cpu(policy->cpu);
 
+	if (!cur_freq)
+		cur_freq = __cpufreq_get(policy);
 	if (cur_freq)
 		return sprintf(buf, "%u\n", cur_freq);
 
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Beata Michalska <beata.michalska@arm.com>
To: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com,
	vanshikonda@os.amperecomputing.com
Cc: sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com,
	vincent.guittot@linaro.org, sumitg@nvidia.com,
	yang@os.amperecomputing.com, lihuisong@huawei.com,
	viresh.kumar@linaro.org
Subject: [PATCH v5 5/5] cpufreq: Use arch specific feedback for cpuinfo_cur_freq
Date: Wed, 17 Apr 2024 10:38:48 +0100	[thread overview]
Message-ID: <20240417093848.1555462-6-beata.michalska@arm.com> (raw)
In-Reply-To: <20240417093848.1555462-1-beata.michalska@arm.com>

Some architectures provide a way to determine an average frequency over
a certain period of time based on available performance monitors (AMU on
ARM or APERF/MPERf on x86). With those at hand, enroll arch_freq_get_on_cpu
into cpuinfo_cur_freq policy sysfs attribute handler, which is expected to
represent the current frequency of a given CPU,as obtained by the hardware.
This is the type of feedback that counters do provide.

Signed-off-by: Beata Michalska <beata.michalska@arm.com>
---
 drivers/cpufreq/cpufreq.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index f6f8d7f450e7..89118406ec68 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -793,8 +793,10 @@ store_one(scaling_max_freq, max);
 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
 					char *buf)
 {
-	unsigned int cur_freq = __cpufreq_get(policy);
+	unsigned int cur_freq = arch_freq_get_on_cpu(policy->cpu);
 
+	if (!cur_freq)
+		cur_freq = __cpufreq_get(policy);
 	if (cur_freq)
 		return sprintf(buf, "%u\n", cur_freq);
 
-- 
2.25.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2024-04-17  9:39 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-17  9:38 [PATCH v5 0/5] Add support for AArch64 AMUv1-based arch_freq_get_on_cpu Beata Michalska
2024-04-17  9:38 ` Beata Michalska
2024-04-17  9:38 ` [PATCH v5 1/5] arch_topology: init capacity_freq_ref to 0 Beata Michalska
2024-04-17  9:38   ` Beata Michalska
2024-04-18 10:50   ` Sudeep Holla
2024-04-18 10:50     ` Sudeep Holla
2024-04-17  9:38 ` [PATCH v5 2/5] arm64: amu: Rule out potential use after free Beata Michalska
2024-04-17  9:38   ` Beata Michalska
2024-04-18 10:50   ` Sudeep Holla
2024-04-18 10:50     ` Sudeep Holla
2024-04-18 15:55     ` Beata Michalska
2024-04-18 15:55       ` Beata Michalska
2024-04-24 10:25       ` Sudeep Holla
2024-04-24 10:25         ` Sudeep Holla
2024-04-25 14:27         ` Beata Michalska
2024-04-25 14:27           ` Beata Michalska
2024-05-07  7:24           ` Ionela Voinescu
2024-05-07  7:24             ` Ionela Voinescu
2024-04-17  9:38 ` [PATCH v5 3/5] arm64: Provide an AMU-based version of arch_freq_get_on_cpu Beata Michalska
2024-04-17  9:38   ` Beata Michalska
2024-04-18  1:39   ` Vanshidhar Konda
2024-04-18  1:39     ` Vanshidhar Konda
2024-04-26 10:50     ` Beata Michalska
2024-04-26 10:50       ` Beata Michalska
2024-04-17  9:38 ` [PATCH v5 4/5] arm64: Update AMU-based frequency scale factor on entering idle Beata Michalska
2024-04-17  9:38   ` Beata Michalska
2024-04-17  9:38 ` Beata Michalska [this message]
2024-04-17  9:38   ` [PATCH v5 5/5] cpufreq: Use arch specific feedback for cpuinfo_cur_freq Beata Michalska

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