* [PATCH v2 1/2] arch_topology: seed capacity_freq_ref with boost-aware max freq
2026-09-08 8:30 [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling Ananthu C V
@ 2026-09-08 8:30 ` Ananthu C V
2026-09-08 8:30 ` [PATCH v2 2/2] cpufreq: fix schedutil not returning to non-boost freq when boost is disabled Ananthu C V
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Ananthu C V @ 2026-09-08 8:30 UTC (permalink / raw)
To: Vincent Guittot, Sudeep Holla, Greg Kroah-Hartman,
Rafael J. Wysocki, Danilo Krummrich, Viresh Kumar
Cc: linux-kernel, driver-core, linux-pm, Ananthu C V
capacity_freq_ref, the per-CPU frequency-invariance reference used by
schedutil, is seeded from policy->cpuinfo.max_freq at policy creation.
If boost frequencies are filtered out of the frequency table because
boost isn't yet enabled at boot, max_freq only reflects the non-boost
ceiling, so capacity_freq_ref never learns about boost frequencies for
the policy's lifetime. Enabling boost later raises policy->max, but
capacity_freq_ref stays stale, leaving schedutil unable to scale
utilization or target a frequency above the non-boost maximum.
Track the highest frequency in the table regardless of boost state
(max_table_freq) and seed capacity_freq_ref with max(cpuinfo.max_freq,
max_table_freq), so the invariance reference is boost-aware from boot
regardless of whether boost is currently enabled. Runtime enforcement,
still handled by policy->max, is unaffected.
Suggested-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ananthu C V <ananthu.cv@oss.qualcomm.com>
---
drivers/base/arch_topology.c | 3 ++-
drivers/cpufreq/freq_table.c | 6 ++++++
include/linux/cpufreq.h | 1 +
3 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 8c5e47c28d9a..da94f77441da 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -404,7 +404,8 @@ init_cpu_capacity_callback(struct notifier_block *nb,
cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
for_each_cpu(cpu, policy->related_cpus) {
- per_cpu(capacity_freq_ref, cpu) = policy->cpuinfo.max_freq;
+ per_cpu(capacity_freq_ref, cpu) = max(policy->cpuinfo.max_freq,
+ policy->cpuinfo.max_table_freq);
freq_inv_set_max_ratio(cpu,
per_cpu(capacity_freq_ref, cpu) * HZ_PER_KHZ);
}
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index ea994647abc8..4984142dc08a 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -33,11 +33,15 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
struct cpufreq_frequency_table *pos, *table = policy->freq_table;
unsigned int min_freq = ~0;
unsigned int max_freq = 0;
+ unsigned int max_table_freq = 0;
unsigned int freq, i;
cpufreq_for_each_valid_entry_idx(pos, table, i) {
freq = pos->frequency;
+ if (freq > max_table_freq)
+ max_table_freq = freq;
+
if ((!cpufreq_boost_enabled() || !policy->boost_enabled)
&& (pos->flags & CPUFREQ_BOOST_FREQ))
continue;
@@ -57,6 +61,8 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
if (policy->cpuinfo.max_freq < max_freq)
policy->cpuinfo.max_freq = max_freq;
+ policy->cpuinfo.max_table_freq = max_table_freq;
+
if (min_freq == ~0)
return -EINVAL;
else
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 35ce665edfd8..3f3b1380251a 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -45,6 +45,7 @@ enum cpufreq_table_sorting {
struct cpufreq_cpuinfo {
unsigned int max_freq;
unsigned int min_freq;
+ unsigned int max_table_freq; /* Highest valid frequency in the table */
/* in 10^(-9) s = nanoseconds */
unsigned int transition_latency;
--
2.43.0
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v2 2/2] cpufreq: fix schedutil not returning to non-boost freq when boost is disabled
2026-09-08 8:30 [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling Ananthu C V
2026-09-08 8:30 ` [PATCH v2 1/2] arch_topology: seed capacity_freq_ref with boost-aware max freq Ananthu C V
@ 2026-09-08 8:30 ` Ananthu C V
2026-09-08 10:03 ` [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling Ananthu C V
2026-09-14 16:27 ` Dietmar Eggemann
3 siblings, 0 replies; 5+ messages in thread
From: Ananthu C V @ 2026-09-08 8:30 UTC (permalink / raw)
To: Vincent Guittot, Sudeep Holla, Greg Kroah-Hartman,
Rafael J. Wysocki, Danilo Krummrich, Viresh Kumar
Cc: linux-kernel, driver-core, linux-pm, Ananthu C V
Commit 538b0188da46 ("cpufreq: ACPI: Set cpuinfo.max_freq directly if
max boost is known") introduced a guard for cpuinfo max updates to only
increase, to preserve driver-set values above the freq table maximum,
causing cpuinfo max to be stuck at boost frequency even when boost is
disabled.
Unconditionally track the highest non-boost frequency (max_base_freq)
in the freq table. When a freq table is available, use max_table_freq/
max_base_freq instead of cpuinfo->max_freq to control boost values, so
the value can decrease again when boost is disabled.
Fixes: 538b0188da46 ("cpufreq: ACPI: Set cpuinfo.max_freq directly if max boost is known")
Signed-off-by: Ananthu C V <ananthu.cv@oss.qualcomm.com>
---
drivers/cpufreq/cpufreq.c | 14 +++++++++++++-
drivers/cpufreq/freq_table.c | 5 +++++
include/linux/cpufreq.h | 1 +
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0d0df986fa3d..a13e72711597 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -574,6 +574,7 @@ static ssize_t show_local_boost(struct cpufreq_policy *policy, char *buf)
static int policy_set_boost(struct cpufreq_policy *policy, bool enable)
{
+ unsigned int max_freq;
int ret;
if (policy->boost_enabled == enable)
@@ -587,7 +588,18 @@ static int policy_set_boost(struct cpufreq_policy *policy, bool enable)
return ret;
}
- ret = freq_qos_update_request(&policy->boost_freq_req, policy->cpuinfo.max_freq);
+ if (policy->freq_table) {
+ max_freq = enable ? policy->cpuinfo.max_table_freq :
+ policy->cpuinfo.max_base_freq;
+
+ if (!max_freq)
+ /* when the freq table contains only boost frequencies */
+ max_freq = policy->cpuinfo.max_table_freq;
+ } else {
+ max_freq = policy->cpuinfo.max_freq;
+ }
+
+ ret = freq_qos_update_request(&policy->boost_freq_req, max_freq);
if (ret < 0) {
policy->boost_enabled = !policy->boost_enabled;
cpufreq_driver->set_boost(policy, policy->boost_enabled);
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 4984142dc08a..7e183e16162d 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -34,6 +34,7 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
unsigned int min_freq = ~0;
unsigned int max_freq = 0;
unsigned int max_table_freq = 0;
+ unsigned int max_base_freq = 0;
unsigned int freq, i;
cpufreq_for_each_valid_entry_idx(pos, table, i) {
@@ -42,6 +43,9 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
if (freq > max_table_freq)
max_table_freq = freq;
+ if (!(pos->flags & CPUFREQ_BOOST_FREQ) && freq > max_base_freq)
+ max_base_freq = freq;
+
if ((!cpufreq_boost_enabled() || !policy->boost_enabled)
&& (pos->flags & CPUFREQ_BOOST_FREQ))
continue;
@@ -62,6 +66,7 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
policy->cpuinfo.max_freq = max_freq;
policy->cpuinfo.max_table_freq = max_table_freq;
+ policy->cpuinfo.max_base_freq = max_base_freq;
if (min_freq == ~0)
return -EINVAL;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 3f3b1380251a..419c71ccff7c 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -46,6 +46,7 @@ struct cpufreq_cpuinfo {
unsigned int max_freq;
unsigned int min_freq;
unsigned int max_table_freq; /* Highest valid frequency in the table */
+ unsigned int max_base_freq; /* Highest non-boost frequency in the table */
/* in 10^(-9) s = nanoseconds */
unsigned int transition_latency;
--
2.43.0
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling
2026-09-08 8:30 [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling Ananthu C V
2026-09-08 8:30 ` [PATCH v2 1/2] arch_topology: seed capacity_freq_ref with boost-aware max freq Ananthu C V
2026-09-08 8:30 ` [PATCH v2 2/2] cpufreq: fix schedutil not returning to non-boost freq when boost is disabled Ananthu C V
@ 2026-09-08 10:03 ` Ananthu C V
2026-09-14 16:27 ` Dietmar Eggemann
3 siblings, 0 replies; 5+ messages in thread
From: Ananthu C V @ 2026-09-08 10:03 UTC (permalink / raw)
To: Vincent Guittot, Sudeep Holla, Greg Kroah-Hartman,
Rafael J. Wysocki, Danilo Krummrich, Viresh Kumar
Cc: linux-kernel, driver-core, linux-pm
It seems some mangling was done and all lines starting with hashes
were considered comments and ignored, malforming the logs. Apologies
for that, this is how it's supposed to look :)
Before fix
----------
# cd /sys/devices/system/cpu/cpufreq/
# ls
boost policy0 policy12 policy6
# cat boost
0
# cat policy6/scaling_max_freq
4454400
# echo 1 > boost
# cat policy6/scaling_max_freq
4723200
# echo 0 > boost
# cat policy6/scaling_max_freq
4723200
4723200
# echo 1 > boost
# cat policy6/stats/time_in_state
355200 36958
4454400 650
4588800 0
4723200 0
After fix
---------
# cd /sys/devices/system/cpu/cpufreq/
# ls
boost policy0 policy12 policy6
# cat boost
0
# cat policy6/scaling_max_freq
4454400
# echo 1 > boost
# cat policy6/scaling_max_freq
4723200
# echo 0 > policy6/boost
# cat policy6/scaling_max_freq
4454400
# cat policy6/boost
0
# cat policy6/stats/time_in_state
355200 40147
4454400 79
4588800 0
4723200 0
# echo 1 > policy6/boost
# cat policy6/stats/time_in_state
355200 44834
4454400 93
4588800 25
4723200 569
Best,
Ananthu
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling
2026-09-08 8:30 [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling Ananthu C V
` (2 preceding siblings ...)
2026-09-08 10:03 ` [PATCH v2 0/2] sched/cpufreq: fix schedutil's boost frequency handling Ananthu C V
@ 2026-09-14 16:27 ` Dietmar Eggemann
3 siblings, 0 replies; 5+ messages in thread
From: Dietmar Eggemann @ 2026-09-14 16:27 UTC (permalink / raw)
To: Ananthu C V, Vincent Guittot, Sudeep Holla, Greg Kroah-Hartman,
Rafael J. Wysocki, Danilo Krummrich, Viresh Kumar
Cc: linux-kernel, driver-core, linux-pm
On 08.09.26 10:30, Ananthu C V wrote:
> Schedutil's ability to reach boost frequencies depends on two values
> being correct: policy max, which caps the resolved target frequency,
> and the per-CPU capacity frequency reference, which anchors the
> utilization-to-frequency mapping.
>
> This series fixes a few gaps in how these values are maintained across
> boost transitions:
>
> The per-CPU capacity frequency reference is set once at policy
> creation and never updated when boost is enabled afterwards, leaving
> schedutil unable to target boost frequencies even at full utilization.
> Track the max available (boost inclusive) frequency before policy
> comes online and use it to seed the capacity_freq_ref value, allowing
> schedutil to utilize the boost frequency values when boost is enabled
> later.
>
> The generic boost callback only raises cpuinfo max, never lowers it.
> Once boost is enabled, disabling it leaves cpuinfo max pinned at the
> boost ceiling, keeping policy max stuck there too. Also track the max
> available non-boost frequency and use the newly tracked max values to
> control boost frequencies when a frequency table is available, allowing
> the frequency to drop back to non boost values on boost disable. In
> the absense of a frequency table, the handling will fall back to using
> cpuinfo->max_freq, preserving the current behaviour.
>
> Logs below for clear context:
> Intermediate values from the time_in_state output and logs from bench
> runs are truncated for brevity.
>
> Before fix
> ----------
>
> boost policy0 policy12 policy6
>
> 0
>
> 4454400
>
> 4723200
>
> 4723200
>
> 355200 36958
> 4454400 650
> 4588800 0
> 4723200 0
>
> After fix
> ---------
>
> boost policy0 policy12 policy6
>
> 0
>
> 4454400
>
> 4723200
>
> 4454400
>
> 0
>
> 355200 40147
> 4454400 79
> 4588800 0
> 4723200 0
>
> 355200 44834
> 4454400 93
> 4588800 25
> 4723200 569
>
> Signed-off-by: Ananthu C V <ananthu.cv@oss.qualcomm.com>
> ---
> Ananthu C V (2):
> arch_topology: seed capacity_freq_ref with boost-aware max freq
> cpufreq: fix schedutil not returning to non-boost freq when boost is disabled
>
> drivers/base/arch_topology.c | 3 ++-
> drivers/cpufreq/cpufreq.c | 14 +++++++++++++-
> drivers/cpufreq/freq_table.c | 11 +++++++++++
> include/linux/cpufreq.h | 2 ++
> 4 files changed, 28 insertions(+), 2 deletions(-)
> ---
> base-commit: 32b6ef9a5d0eca44f9cd91f52f4faa89f145a0de
> change-id: 20260804-schedutil-boost-frequency-handling-8e6bf2387a4a
IMHO, this makes sense, also the coordination via cpufreq_pressure
(policy->max).
On ARM64 Juno R0:
# cat /sys/devices/system/cpu/cpu*/cpu_capacity
446
1024
1024
446
446
446
# cat /sys/devices/system/cpu/cpufreq/boost
0
cat
/sys/devices/system/cpu/cpu{0,1}/cpufreq/scaling_{available,boost}_frequencies
450000 575000 700000
775000 850000
450000 625000 800000
950000 1100000
# cat /sys/devices/system/cpu/cpu{0,1}/cpufreq/cpuinfo_{min,max}_freq
450000
700000
450000
800000
# dmsg | grep policy
[3.323564] cpufreq_update_pressure(): policy->related_cpus=[0,3-5]
policy->max=700000 pressure=102 (*)
[3.333206] cpufreq_update_pressure(): policy->related_cpus=[1-2]
policy->max=800000 pressure=280
# echo 1 > /sys/devices/system/cpu/cpufreq/boost
# dmsg | grep policy
[ 1511.188932] policy->related_cpus=[1-2] pressure=0
[ 1511.189050] policy->related_cpus=[0,3-5] pressure=0
# echo 0 > /sys/devices/system/cpu/cpufreq/boost
# dmsg | grep policy
[ 204.951039] cpufreq_update_pressure(): policy->related_cpus=[1-2]
policy->max=800000 pressure=280
[ 204.951223] cpufreq_update_pressure(): policy->related_cpus=[0,3-5]
policy->max=700000 pressure=79 (*)
(*) This is the only small issue I see. The pressure=102 is pressure
based on purely uarch differences (max_capacity(0,3-5)=578) whereas
pressure=79 later is based on uarch + max frequency differences
(max_capacity(0,3-5)=446).
^ permalink raw reply [flat|nested] 5+ messages in thread