On Fri, Apr 1, 2016 at 7:49 PM, Steve Muckle <steve.muc...@linaro.org> wrote:
> On 03/29/2016 07:00 PM, Rafael J. Wysocki wrote:
> ...
>> +config CPU_FREQ_GOV_SCHEDUTIL
>> + tristate "'schedutil' cpufreq policy governor"
>> + depends on CPU_FREQ
>> + select CPU_FREQ_GOV_ATTR_SET
>> + select IRQ_WORK
>> + help
>> + This governor makes decisions based on the utilization data provided
>> + by the scheduler. It sets the CPU frequency to be proportional to
>> + the utilization/capacity ratio coming from the scheduler. If the
>> + utilization is frequency-invariant, the new frequency is also
>> + proportional to the maximum available frequency. If that is not the
>> + case, it is proportional to the current frequency of the CPU with the
>> + tipping point at utilization/capacity equal to 80%.
>
> This help text implies that the tipping point of 80% applies only to
> non-frequency invariant configurations, rather than both. Possible to
> rephrase?
Sure.
What about:
"If that is not the case, it is proportional to the current frequency
of the CPU. The frequency tipping point is at utilization/capacity
equal to 80% in both cases."
> ...
>> +static unsigned int sugov_next_freq_shared(struct sugov_policy *sg_policy,
>> + unsigned long util, unsigned long
>> max)
>> +{
>> + struct cpufreq_policy *policy = sg_policy->policy;
>> + unsigned int max_f = policy->cpuinfo.max_freq;
>> + u64 last_freq_update_time = sg_policy->last_freq_update_time;
>> + unsigned int j;
>> +
>> + if (util == ULONG_MAX)
>> + return max_f;
>> +
>> + for_each_cpu(j, policy->cpus) {
>> + struct sugov_cpu *j_sg_cpu;
>> + unsigned long j_util, j_max;
>> + u64 delta_ns;
>> +
>> + if (j == smp_processor_id())
>> + continue;
>> +
>> + j_sg_cpu = &per_cpu(sugov_cpu, j);
>> + /*
>> + * If the CPU utilization was last updated before the previous
>> + * frequency update and the time elapsed between the last
>> update
>> + * of the CPU utilization and the last frequency update is long
>> + * enough, don't take the CPU into account as it probably is
>> + * idle now.
>> + */
>> + delta_ns = last_freq_update_time - j_sg_cpu->last_update;
>> + if ((s64)delta_ns > TICK_NSEC)
>
>>> Why not declare delta_ns as an s64 (also in suguv_should_update_freq)
>>> and avoid the cast?
>>
>> I took this from __update_load_avg(), but it shouldn't matter here.
>
> Did you mean to keep these casts?
Not really. I'll fix that up shortly.
