Messages in this thread Patch in this message | | | From | Beata Michalska <> | Subject | [PATCH v5 1/5] arch_topology: init capacity_freq_ref to 0 | Date | Wed, 17 Apr 2024 10:38:44 +0100 |
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From: Ionela Voinescu <ionela.voinescu@arm.com>
It's useful to have capacity_freq_ref initialized to 0 for users of arch_scale_freq_ref() to detect when capacity_freq_ref was not yet set.
The only scenario affected by this change in the init value is when a cpufreq driver is never loaded. As a result, the only setter of a cpu scale factor remains the call of topology_normalize_cpu_scale() from parse_dt_topology(). There we cannot use the value 0 of capacity_freq_ref so we have to compensate for its uninitialized state.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Beata Michalska <beata.michalska@arm.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> --- drivers/base/arch_topology.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 024b78a0cfc1..7d4c92cd2bad 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -27,7 +27,7 @@ static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); static struct cpumask scale_freq_counters_mask; static bool scale_freq_invariant; -DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 1; +DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 0; EXPORT_PER_CPU_SYMBOL_GPL(capacity_freq_ref); static bool supports_scale_freq_counters(const struct cpumask *cpus) @@ -292,13 +292,15 @@ void topology_normalize_cpu_scale(void) capacity_scale = 1; for_each_possible_cpu(cpu) { - capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity = raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity_scale = max(capacity, capacity_scale); } pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale); for_each_possible_cpu(cpu) { - capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu); + capacity = raw_capacity[cpu] * + (per_cpu(capacity_freq_ref, cpu) ?: 1); capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT, capacity_scale); topology_set_cpu_scale(cpu, capacity); -- 2.25.1
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