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intel_pstate: Add num_pstates to sysfs 

Add a sysfs interface to display the total number of supported
pstates.  This value is independent of whether turbo has been
enabled or disabled.

Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Kristen Carlson Accardi 2015-01-28 15:03:28 -08:00 committed by Rafael J. Wysocki
parent d01b1f48c5
commit 0522424ecb
2 changed files with 17 additions and 0 deletions
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4
Documentation/cpu-freq/intel-pstate.txt
View File

@ -41,6 +41,10 @@ controlling P state selection. These files have been added to
is supported by hardware that is in the turbo range. This number
is independent of whether turbo has been disabled or not.
num_pstates: displays the number of pstates that are supported
by hardware. This number is independent of whether turbo has
been disabled or not.
For contemporary Intel processors, the frequency is controlled by the
processor itself and the P-states exposed to software are related to
performance levels. The idea that frequency can be set to a single

13
drivers/cpufreq/intel_pstate.c
View File

@ -354,6 +354,17 @@ static ssize_t show_turbo_pct(struct kobject *kobj,
return sprintf(buf, "%u\n", turbo_pct);
}
static ssize_t show_num_pstates(struct kobject *kobj,
struct attribute *attr, char *buf)
{
struct cpudata *cpu;
int total;
cpu = all_cpu_data[0];
total = cpu->pstate.turbo_pstate - cpu->pstate.min_pstate + 1;
return sprintf(buf, "%u\n", total);
}
static ssize_t show_no_turbo(struct kobject *kobj,
struct attribute *attr, char *buf)
{
@ -435,12 +446,14 @@ define_one_global_rw(no_turbo);
define_one_global_rw(max_perf_pct);
define_one_global_rw(min_perf_pct);
define_one_global_ro(turbo_pct);
define_one_global_ro(num_pstates);
static struct attribute *intel_pstate_attributes[] = {
&no_turbo.attr,
&max_perf_pct.attr,
&min_perf_pct.attr,
&turbo_pct.attr,
&num_pstates.attr,
NULL
};