On 06/06/13 19:06, Rafael J. Wysocki wrote:
> On Thursday, June 06, 2013 08:27:08 AM Joe Jin wrote:
>> On 06/06/13 04:40, Rafael J. Wysocki wrote:
>>> On Wednesday, June 05, 2013 08:52:52 AM Joe Jin wrote:
>>>> When _PPC changed dynamically the user_policy.max will not be updated,
>>>> this prevent CPU run on the highest frequency.
>>>
>>> Why should the user setting be always related to the current maximum available
>>> frequency? What if the user sets the limit for power capping purposes?
>>
>> cpufreq_update_policy() get policy->max from user_policy.max:
>>
>> 1782 int cpufreq_update_policy(unsigned int cpu)
>> 1783 {
>> [...]
>> 1800 policy.min = data->user_policy.min;
>> 1801 policy.max = data->user_policy.max;
>> 1802 policy.policy = data->user_policy.policy;
>> 1803 policy.governor = data->user_policy.governor;
>> [...]
>> 1819 ret = __cpufreq_set_policy(data, &policy);
>> [...]
>>
>> /sys/devices/system/cpu/cpu$/cpufreq/scaling_max_freq using policy->max
>> and user_policy->max, when update it, so I think _PPC changes also need
>> to update these two?
>
> Yes, if policy.max happens to be greater that the maximum available frequency,
> then (and only then) it probably should be updated. It should never be bumped
> up, though.
Does this means if I enabled hardcap before kernel boot up, and later system brought
up and I disabled hardcap, I has to enlarge the max frequency manually?
Thanks,
Joe
>
> Thanks,
> Rafael
>
>
>>>> Signed-off-by: Joe Jin <joe.jin@xxxxxxxxxx>
>>>> Cc: Rafael J. Wysocki <rjw@xxxxxxx>
>>>> Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
>>>> ---
>>>> drivers/acpi/processor_perflib.c | 17 ++++++++++++++++-
>>>> 1 file changed, 16 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
>>>> index e854582..e01aa7d 100644
>>>> --- a/drivers/acpi/processor_perflib.c
>>>> +++ b/drivers/acpi/processor_perflib.c
>>>> @@ -180,6 +180,7 @@ static void acpi_processor_ppc_ost(acpi_handle handle, int status)
>>>> int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
>>>> {
>>>> int ret;
>>>> + unsigned int saved = (unsigned int)pr->performance_platform_limit;
>>>>
>>>> if (ignore_ppc) {
>>>> /*
>>>> @@ -204,8 +205,22 @@ int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
>>>> }
>>>> if (ret < 0)
>>>> return (ret);
>>>> - else
>>>> + else {
>>>> + unsigned int ppc = (unsigned int)pr->performance_platform_limit;
>>>> +
>>>> + if (saved != ppc) {
>>>> + struct cpufreq_policy *policy;
>>>> +
>>>> + policy = cpufreq_cpu_get(pr->id);
>>>> + if (likely(policy))
>>>> + policy->user_policy.max =
>>>> + pr->performance->states[ppc].
>>>> + core_frequency * 1000;
>>>> + cpufreq_cpu_put(policy);
>>>> + }
>>>> +
>>>> return cpufreq_update_policy(pr->id);
>>>> + }
>>>> }
>>>>
>>>> int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
>>>>
>>
>>
>>
--
Oracle <http://www.oracle.com>
Joe Jin | Software Development Senior Manager | +8610.6106.5624
ORACLE | Linux and Virtualization
No. 24 Zhongguancun Software Park, Haidian District | 100193 Beijing
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