| Message ID | 20161104165536.20088-3-code@mmayer.net (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 04-11-16, 09:55, Markus Mayer wrote: > From: Markus Mayer <mmayer@broadcom.com> > > Allow CPUfreq statistics to be cleared by writing anything to > /sys/.../cpufreq/stats/reset. > > Signed-off-by: Markus Mayer <mmayer@broadcom.com> > --- > 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.
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