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cpufreq: cache tunables for ondemand and conservative governors
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This makes them work better with big.LITTLE setups.  Previously, all big cluster tunables were lost when a cluster went offline.

Signed-off-by: Luca Grifo <lg@linux.com>
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@flar2 @morogoku
flar2 authored and morogoku committed Mar 26, 2017
1 parent f7c6380 commit 4747f27
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Showing 4 changed files with 123 additions and 15 deletions.
56 changes: 53 additions & 3 deletions drivers/cpufreq/cpufreq_conservative.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#define MAX_SAMPLING_DOWN_FACTOR (10)

static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info);
static DEFINE_PER_CPU(struct cs_dbs_tuners *, cached_tuners);

static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners,
struct cpufreq_policy *policy)
Expand Down Expand Up @@ -317,14 +318,29 @@ static struct attribute_group cs_attr_group_gov_pol = {

/************************** sysfs end ************************/

static int cs_init(struct dbs_data *dbs_data)
static void save_tuners(struct cpufreq_policy *policy,
struct cs_dbs_tuners *tuners)
{
int cpu;

if (have_governor_per_policy())
cpu = cpumask_first(policy->related_cpus);
else
cpu = 0;

WARN_ON(per_cpu(cached_tuners, cpu) &&
per_cpu(cached_tuners, cpu) != tuners);
per_cpu(cached_tuners, cpu) = tuners;
}

static struct cs_dbs_tuners *alloc_tuners(struct cpufreq_policy *policy)
{
struct cs_dbs_tuners *tuners;

tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
if (!tuners) {
pr_err("%s: kzalloc failed\n", __func__);
return -ENOMEM;
return ERR_PTR(-ENOMEM);
}

tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
Expand All @@ -333,6 +349,34 @@ static int cs_init(struct dbs_data *dbs_data)
tuners->ignore_nice_load = 0;
tuners->freq_step = DEF_FREQUENCY_STEP;

save_tuners(policy, tuners);

return tuners;
}

static struct cs_dbs_tuners *restore_tuners(struct cpufreq_policy *policy)
{
int cpu;

if (have_governor_per_policy())
cpu = cpumask_first(policy->related_cpus);
else
cpu = 0;

return per_cpu(cached_tuners, cpu);
}

static int cs_init(struct dbs_data *dbs_data, struct cpufreq_policy *policy)
{
struct cs_dbs_tuners *tuners;

tuners = restore_tuners(policy);
if (!tuners) {
tuners = alloc_tuners(policy);
if (IS_ERR(tuners))
return PTR_ERR(tuners);
}

dbs_data->tuners = tuners;
dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
jiffies_to_usecs(10);
Expand All @@ -342,7 +386,7 @@ static int cs_init(struct dbs_data *dbs_data)

static void cs_exit(struct dbs_data *dbs_data)
{
kfree(dbs_data->tuners);
//nothing to do
}

define_get_cpu_dbs_routines(cs_cpu_dbs_info);
Expand Down Expand Up @@ -391,7 +435,13 @@ static int __init cpufreq_gov_dbs_init(void)

static void __exit cpufreq_gov_dbs_exit(void)
{
int cpu;

cpufreq_unregister_governor(&cpufreq_gov_conservative);
for_each_possible_cpu(cpu) {
kfree(per_cpu(cached_tuners, cpu));
per_cpu(cached_tuners, cpu) = NULL;
}
}

MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
Expand Down
2 changes: 1 addition & 1 deletion drivers/cpufreq/cpufreq_governor.c
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Original file line number Diff line number Diff line change
Expand Up @@ -286,7 +286,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,

dbs_data->cdata = cdata;
dbs_data->usage_count = 1;
rc = cdata->init(dbs_data);
rc = cdata->init(dbs_data, policy);
if (rc) {
pr_err("%s: POLICY_INIT: init() failed\n", __func__);
kfree(dbs_data);
Expand Down
2 changes: 1 addition & 1 deletion drivers/cpufreq/cpufreq_governor.h
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Original file line number Diff line number Diff line change
Expand Up @@ -208,7 +208,7 @@ struct common_dbs_data {
void *(*get_cpu_dbs_info_s)(int cpu);
void (*gov_dbs_timer)(struct work_struct *work);
void (*gov_check_cpu)(int cpu, unsigned int load);
int (*init)(struct dbs_data *dbs_data);
int (*init)(struct dbs_data *dbs_data, struct cpufreq_policy *policy);
void (*exit)(struct dbs_data *dbs_data);

/* Governor specific ops, see below */
Expand Down
78 changes: 68 additions & 10 deletions drivers/cpufreq/cpufreq_ondemand.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#define MAX_FREQUENCY_UP_THRESHOLD (100)

static DEFINE_PER_CPU(struct od_cpu_dbs_info_s, od_cpu_dbs_info);
static DEFINE_PER_CPU(struct od_dbs_tuners *, cached_tuners);

static struct od_ops od_ops;

Expand Down Expand Up @@ -479,7 +480,22 @@ static struct attribute_group od_attr_group_gov_pol = {

/************************** sysfs end ************************/

static int od_init(struct dbs_data *dbs_data)
static void save_tuners(struct cpufreq_policy *policy,
struct od_dbs_tuners *tuners)
{
int cpu;

if (have_governor_per_policy())
cpu = cpumask_first(policy->related_cpus);
else
cpu = 0;

WARN_ON(per_cpu(cached_tuners, cpu) &&
per_cpu(cached_tuners, cpu) != tuners);
per_cpu(cached_tuners, cpu) = tuners;
}

static struct od_dbs_tuners *alloc_tuners(struct cpufreq_policy *policy)
{
struct od_dbs_tuners *tuners;
u64 idle_time;
Expand All @@ -488,7 +504,7 @@ static int od_init(struct dbs_data *dbs_data)
tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
if (!tuners) {
pr_err("%s: kzalloc failed\n", __func__);
return -ENOMEM;
return ERR_PTR(-ENOMEM);
}

cpu = get_cpu();
Expand All @@ -497,33 +513,69 @@ static int od_init(struct dbs_data *dbs_data)
if (idle_time != -1ULL) {
/* Idle micro accounting is supported. Use finer thresholds */
tuners->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
} else {
tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
}

tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
tuners->ignore_nice_load = 0;
tuners->powersave_bias = default_powersave_bias;
tuners->io_is_busy = should_io_be_busy();

save_tuners(policy, tuners);

return tuners;
}

static struct od_dbs_tuners *restore_tuners(struct cpufreq_policy *policy)
{
int cpu;

if (have_governor_per_policy())
cpu = cpumask_first(policy->related_cpus);
else
cpu = 0;

return per_cpu(cached_tuners, cpu);
}

static int od_init(struct dbs_data *dbs_data, struct cpufreq_policy *policy)
{
struct od_dbs_tuners *tuners;
u64 idle_time;
int cpu;

tuners = restore_tuners(policy);
if (!tuners) {
tuners = alloc_tuners(policy);
if (IS_ERR(tuners))
return PTR_ERR(tuners);
}

cpu = get_cpu();
idle_time = get_cpu_idle_time_us(cpu, NULL);
put_cpu();
if (idle_time != -1ULL) {
/*
* In nohz/micro accounting case we set the minimum frequency
* not depending on HZ, but fixed (very low). The deferred
* timer might skip some samples if idle/sleeping as needed.
*/
dbs_data->min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
} else {
tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;

/* For correct statistics, we need 10 ticks for each measure */
dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
jiffies_to_usecs(10);
}

tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
tuners->ignore_nice_load = 0;
tuners->powersave_bias = default_powersave_bias;
tuners->io_is_busy = should_io_be_busy();

dbs_data->tuners = tuners;
mutex_init(&dbs_data->mutex);
return 0;
}

static void od_exit(struct dbs_data *dbs_data)
{
kfree(dbs_data->tuners);
//nothing to do
}

define_get_cpu_dbs_routines(od_cpu_dbs_info);
Expand Down Expand Up @@ -618,7 +670,13 @@ static int __init cpufreq_gov_dbs_init(void)

static void __exit cpufreq_gov_dbs_exit(void)
{
int cpu;

cpufreq_unregister_governor(&cpufreq_gov_ondemand);
for_each_possible_cpu(cpu) {
kfree(per_cpu(cached_tuners, cpu));
per_cpu(cached_tuners, cpu) = NULL;
}
}

MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
Expand Down

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