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cpufreq: Persist cpufreq time in state data across hotplug
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Cpufreq time_in_state data for all CPUs is made persistent across
hotplug and exposed to userspace via sysfs file
/sys/devices/system/cpu/cpufreq/all_time_in_state

Change-Id: I97cb5de24b6de16189bf8b5df9592d0a6e6ddf32
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
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Ruchi Kandoi committed Jun 13, 2014
1 parent 4c7894c commit 40cf2f8
Showing 1 changed file with 223 additions and 1 deletion.
224 changes: 223 additions & 1 deletion drivers/cpufreq/cpufreq_stats.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,8 @@
#include <linux/kobject.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
#include <linux/sort.h>
#include <linux/err.h>
#include <asm/cputime.h>

static spinlock_t cpufreq_stats_lock;
Expand All @@ -38,6 +40,20 @@ struct cpufreq_stats {
#endif
};

struct all_cpufreq_stats {
unsigned int state_num;
cputime64_t *time_in_state;
unsigned int *freq_table;
};

struct all_freq_table {
unsigned int *freq_table;
unsigned int table_size;
};

static struct all_freq_table *all_freq_table;

static DEFINE_PER_CPU(struct all_cpufreq_stats *, all_cpufreq_stats);
static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);

struct cpufreq_stats_attribute {
Expand All @@ -48,14 +64,24 @@ struct cpufreq_stats_attribute {
static int cpufreq_stats_update(unsigned int cpu)
{
struct cpufreq_stats *stat;
struct all_cpufreq_stats *all_stat;
unsigned long long cur_time;

cur_time = get_jiffies_64();
spin_lock(&cpufreq_stats_lock);
stat = per_cpu(cpufreq_stats_table, cpu);
if (stat->time_in_state)
all_stat = per_cpu(all_cpufreq_stats, cpu);
if (!stat) {
spin_unlock(&cpufreq_stats_lock);
return 0;
}
if (stat->time_in_state) {
stat->time_in_state[stat->last_index] +=
cur_time - stat->last_time;
if (all_stat)
all_stat->time_in_state[stat->last_index] +=
cur_time - stat->last_time;
}
stat->last_time = cur_time;
spin_unlock(&cpufreq_stats_lock);
return 0;
Expand Down Expand Up @@ -86,6 +112,62 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
return len;
}

static int get_index_all_cpufreq_stat(struct all_cpufreq_stats *all_stat,
unsigned int freq)
{
int i;
if (!all_stat)
return -1;
for (i = 0; i < all_stat->state_num; i++) {
if (all_stat->freq_table[i] == freq)
return i;
}
return -1;
}

static ssize_t show_all_time_in_state(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
ssize_t len = 0;
unsigned int i, cpu, freq, index;
struct all_cpufreq_stats *all_stat;
struct cpufreq_policy *policy;

len += scnprintf(buf + len, PAGE_SIZE - len, "freq\t\t");
for_each_possible_cpu(cpu) {
len += scnprintf(buf + len, PAGE_SIZE - len, "cpu%d\t\t", cpu);
if (cpu_online(cpu))
cpufreq_stats_update(cpu);
}

if (!all_freq_table)
goto out;
for (i = 0; i < all_freq_table->table_size; i++) {
freq = all_freq_table->freq_table[i];
len += scnprintf(buf + len, PAGE_SIZE - len, "\n%u\t\t", freq);
for_each_possible_cpu(cpu) {
policy = cpufreq_cpu_get(cpu);
if (policy == NULL)
continue;
all_stat = per_cpu(all_cpufreq_stats, policy->cpu);
index = get_index_all_cpufreq_stat(all_stat, freq);
if (index != -1) {
len += scnprintf(buf + len, PAGE_SIZE - len,
"%llu\t\t", (unsigned long long)
cputime64_to_clock_t(all_stat->time_in_state[index]));
} else {
len += scnprintf(buf + len, PAGE_SIZE - len,
"N/A\t\t");
}
cpufreq_cpu_put(policy);
}
}

out:
len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
return len;
}

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
{
Expand Down Expand Up @@ -149,6 +231,9 @@ static struct attribute_group stats_attr_group = {
.name = "stats"
};

static struct kobj_attribute _attr_all_time_in_state = __ATTR(all_time_in_state,
0444, show_all_time_in_state, NULL);

static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
{
int index;
Expand Down Expand Up @@ -195,6 +280,29 @@ static void cpufreq_stats_free_sysfs(unsigned int cpu)
cpufreq_cpu_put(policy);
}

static void cpufreq_allstats_free(void)
{
int i;
struct all_cpufreq_stats *all_stat;

sysfs_remove_file(cpufreq_global_kobject,
&_attr_all_time_in_state.attr);

for (i = 0; i < total_cpus; i++) {
all_stat = per_cpu(all_cpufreq_stats, i);
if (!all_stat)
continue;
kfree(all_stat->time_in_state);
kfree(all_stat);
per_cpu(all_cpufreq_stats, i) = NULL;
}
if (all_freq_table) {
kfree(all_freq_table->freq_table);
kfree(all_freq_table);
all_freq_table = NULL;
}
}

static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *table)
{
Expand Down Expand Up @@ -281,6 +389,106 @@ static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
stat->cpu = policy->cpu;
}

static int compare_for_sort(const void *lhs_ptr, const void *rhs_ptr)
{
unsigned int lhs = *(const unsigned int *)(lhs_ptr);
unsigned int rhs = *(const unsigned int *)(rhs_ptr);
if (lhs < rhs)
return -1;
if (lhs > rhs)
return 1;
return 0;
}

static bool check_all_freq_table(unsigned int freq)
{
int i;
for (i = 0; i < all_freq_table->table_size; i++) {
if (freq == all_freq_table->freq_table[i])
return true;
}
return false;
}

static void create_all_freq_table(void)
{
all_freq_table = kzalloc(sizeof(struct all_freq_table),
GFP_KERNEL);
if (!all_freq_table)
pr_warn("could not allocate memory for all_freq_table\n");
return;
}

static void add_all_freq_table(unsigned int freq)
{
unsigned int size;
size = sizeof(unsigned int) * (all_freq_table->table_size + 1);
all_freq_table->freq_table = krealloc(all_freq_table->freq_table,
size, GFP_KERNEL);
if (IS_ERR(all_freq_table->freq_table)) {
pr_warn("Could not reallocate memory for freq_table\n");
all_freq_table->freq_table = NULL;
return;
}
all_freq_table->freq_table[all_freq_table->table_size++] = freq;
}

static void cpufreq_allstats_create(unsigned int cpu)
{
int i , j = 0;
unsigned int alloc_size, count = 0;
struct cpufreq_frequency_table *table = cpufreq_frequency_get_table(cpu);
struct all_cpufreq_stats *all_stat;
bool sort_needed = false;

if (!table)
return;

for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
unsigned int freq = table[i].frequency;
if (freq == CPUFREQ_ENTRY_INVALID)
continue;
count++;
}

all_stat = kzalloc(sizeof(struct all_cpufreq_stats),
GFP_KERNEL);
if (!all_stat) {
pr_warn("Cannot allocate memory for cpufreq stats\n");
return;
}

/*Allocate memory for freq table per cpu as well as clockticks per freq*/
alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
all_stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
if (!all_stat->time_in_state) {
pr_warn("Cannot allocate memory for cpufreq time_in_state\n");
kfree(all_stat);
all_stat = NULL;
return;
}
all_stat->freq_table = (unsigned int *)
(all_stat->time_in_state + count);

spin_lock(&cpufreq_stats_lock);
for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
unsigned int freq = table[i].frequency;
if (freq == CPUFREQ_ENTRY_INVALID)
continue;
all_stat->freq_table[j++] = freq;
if (all_freq_table && !check_all_freq_table(freq)) {
add_all_freq_table(freq);
sort_needed = true;
}
}
if (sort_needed)
sort(all_freq_table->freq_table, all_freq_table->table_size,
sizeof(unsigned int), &compare_for_sort, NULL);
all_stat->state_num = j;
per_cpu(all_cpufreq_stats, cpu) = all_stat;
spin_unlock(&cpufreq_stats_lock);
}

static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
unsigned long val, void *data)
{
Expand All @@ -299,6 +507,10 @@ static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
table = cpufreq_frequency_get_table(cpu);
if (!table)
return 0;

if (!per_cpu(all_cpufreq_stats, cpu))
cpufreq_allstats_create(cpu);

ret = cpufreq_stats_create_table(policy, table);
if (ret)
return ret;
Expand Down Expand Up @@ -355,6 +567,9 @@ static int cpufreq_stats_create_table_cpu(unsigned int cpu)
if (!table)
goto out;

if (!per_cpu(all_cpufreq_stats, cpu))
cpufreq_allstats_create(cpu);

ret = cpufreq_stats_create_table(policy, table);

out:
Expand Down Expand Up @@ -430,6 +645,12 @@ static int __init cpufreq_stats_init(void)
return ret;
}

create_all_freq_table();
ret = sysfs_create_file(cpufreq_global_kobject,
&_attr_all_time_in_state.attr);
if (ret)
pr_warn("Error creating sysfs file for cpufreq stats\n");

return 0;
}
static void __exit cpufreq_stats_exit(void)
Expand All @@ -445,6 +666,7 @@ static void __exit cpufreq_stats_exit(void)
cpufreq_stats_free_table(cpu);
cpufreq_stats_free_sysfs(cpu);
}
cpufreq_allstats_free();
}

MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
Expand Down

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