diff options
| -rw-r--r-- | Documentation/cpu-freq/user-guide.txt | 12 | ||||
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 3 |
2 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt index 917918f84fc..75f41193f3e 100644 --- a/Documentation/cpu-freq/user-guide.txt +++ b/Documentation/cpu-freq/user-guide.txt @@ -152,6 +152,18 @@ cpuinfo_min_freq : this file shows the minimum operating frequency the processor can run at(in kHz) cpuinfo_max_freq : this file shows the maximum operating frequency the processor can run at(in kHz) +cpuinfo_transition_latency The time it takes on this CPU to + switch between two frequencies in nano + seconds. If unknown or known to be + that high that the driver does not + work with the ondemand governor, -1 + (CPUFREQ_ETERNAL) will be returned. + Using this information can be useful + to choose an appropriate polling + frequency for a kernel governor or + userspace daemon. Make sure to not + switch the frequency too often + resulting in performance loss. scaling_driver : this file shows what cpufreq driver is used to set the frequency on this CPU diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 1867dac35af..6fe466efb0b 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -452,6 +452,7 @@ static ssize_t show_##file_name \ show_one(cpuinfo_min_freq, cpuinfo.min_freq); show_one(cpuinfo_max_freq, cpuinfo.max_freq); +show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); show_one(scaling_min_freq, min); show_one(scaling_max_freq, max); show_one(scaling_cur_freq, cur); @@ -659,6 +660,7 @@ __ATTR(_name, 0644, show_##_name, store_##_name) define_one_ro0400(cpuinfo_cur_freq); define_one_ro(cpuinfo_min_freq); define_one_ro(cpuinfo_max_freq); +define_one_ro(cpuinfo_transition_latency); define_one_ro(scaling_available_governors); define_one_ro(scaling_driver); define_one_ro(scaling_cur_freq); @@ -672,6 +674,7 @@ define_one_rw(scaling_setspeed); static struct attribute *default_attrs[] = { &cpuinfo_min_freq.attr, &cpuinfo_max_freq.attr, + &cpuinfo_transition_latency.attr, &scaling_min_freq.attr, &scaling_max_freq.attr, &affected_cpus.attr, |