On 04-11-16, 09:55, Markus Mayer wrote: > 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);
Just drop the perm argument and this patch looks fine as well. -- viresh
