From: Markus Mayer <[email protected]> Allow CPUfreq statistics to be cleared by writing anything to /sys/.../cpufreq/stats/reset.
Signed-off-by: Markus Mayer <[email protected]> --- Documentation/cpu-freq/cpufreq-stats.txt | 6 ++++++ drivers/cpufreq/cpufreq_stats.c | 22 ++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/Documentation/cpu-freq/cpufreq-stats.txt b/Documentation/cpu-freq/cpufreq-stats.txt index 8d9773f..3c355f6 100644 --- a/Documentation/cpu-freq/cpufreq-stats.txt +++ b/Documentation/cpu-freq/cpufreq-stats.txt @@ -44,11 +44,17 @@ the stats driver insertion. total 0 drwxr-xr-x 2 root root 0 May 14 16:06 . drwxr-xr-x 3 root root 0 May 14 15:58 .. +--w------- 1 root root 4096 May 14 16:06 reset -r--r--r-- 1 root root 4096 May 14 16:06 time_in_state -r--r--r-- 1 root root 4096 May 14 16:06 total_trans -r--r--r-- 1 root root 4096 May 14 16:06 trans_table -------------------------------------------------------------------------------- +- reset +Write-only attribute that can be used to reset the stat counters. This can be +useful for evaluating system behaviour under different governors without the +need for a reboot. + - time_in_state This gives the amount of time spent in each of the frequencies supported by this CPU. The cat output will have "<frequency> <time>" pair in each line, which diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c index 06d3abd..66419e6 100644 --- a/drivers/cpufreq/cpufreq_stats.c +++ b/drivers/cpufreq/cpufreq_stats.c @@ -41,6 +41,18 @@ static int cpufreq_stats_update(struct cpufreq_stats *stats) return 0; } +static void cpufreq_stats_clear_table(struct cpufreq_stats *stats) +{ + unsigned int count = stats->max_state; + + memset(stats->time_in_state, 0, count * sizeof(u64)); +#ifdef CONFIG_CPU_FREQ_STAT_DETAILS + memset(stats->trans_table, 0, count * count * sizeof(int)); +#endif + stats->last_time = get_jiffies_64(); + stats->total_trans = 0; +} + static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf) { return sprintf(buf, "%d\n", policy->stats->total_trans); @@ -64,6 +76,14 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf) return len; } +static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf, + size_t count) +{ + /* We don't care what is written to the attribute. */ + cpufreq_stats_clear_table(policy->stats); + return count; +} + #ifdef CONFIG_CPU_FREQ_STAT_DETAILS static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf) { @@ -113,10 +133,12 @@ cpufreq_freq_attr_ro(trans_table); cpufreq_freq_attr_ro(total_trans); cpufreq_freq_attr_ro(time_in_state); +cpufreq_freq_attr_wr_perm(reset, 0200); static struct attribute *default_attrs[] = { &total_trans.attr, &time_in_state.attr, + &reset.attr, #ifdef CONFIG_CPU_FREQ_STAT_DETAILS &trans_table.attr, #endif -- 2.7.4
