diff options
| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2026-07-07 19:25:39 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2026-07-09 20:31:57 +0200 |
| commit | d2d5c129d07ea8eb91cd8a8633b5774116c4d171 (patch) | |
| tree | b721c98f78e3dbe77dbabdaebb3fe0b03f05bdaa | |
| parent | 27d80e0f8b8dff97503fc0061754b1d3800cb961 (diff) | |
cpufreq: Make cpufreq_update_pressure() fall back to cpuinfo.max_freq
If arch_scale_freq_ref() is not defined for a given arch (like x86, for
example), cpufreq_update_pressure() will always set cpufreq_pressure to
zero for all CPUs in the system, which is generally problematic on
systems with asymmetric capacity [1].
However, in the absence of arch_scale_freq_ref(), it is reasonable
to assume that cpuinfo.max_freq is the maximum sustainable frequency
for the given cpufreq policy. Moreover, there are cases in which
arch_scale_freq_ref() would need to be defined to return essentially
the cpuinfo.max_freq value anyway (for example, intel_pstate on
hybrid platforms).
For the above reasons, update cpufreq_update_pressure() to fall back to
using cpuinfo.max_freq as the reference frequency if zero is returned by
arch_scale_freq_ref().
Fixes: 75d659317bb1 ("cpufreq: Add a cpufreq pressure feedback for the scheduler")
Link: https://lore.kernel.org/lkml/CAKfTPtBuRLfYNnR4w--cFZYZy-R8gaPEgVwCcaMmbCcJ2H-muQ@mail.gmail.com/ [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Zhongqiu Han <zhongqiu.han@oss.qualcomm.com>
Tested-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> # cluster scheduling
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://patch.msgid.link/5086499.GXAFRqVoOG@rafael.j.wysocki
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 507224c9ecd3..b898b6544069 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2586,6 +2586,9 @@ static void cpufreq_update_pressure(struct cpufreq_policy *policy) cpu = cpumask_first(policy->related_cpus); max_freq = arch_scale_freq_ref(cpu); + if (!max_freq) + max_freq = policy->cpuinfo.max_freq; + capped_freq = policy->max; /* |