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Commit 3c55215e authored by Amir Vajid's avatar Amir Vajid
Browse files

PM / devfreq: memlat: optimize freq and stall_pct calculations 



Currently, we calculate freq and stall_pct multiple times for
the same shared PMU counters. Calculate these once per cpu_grp
to prevent repeating the same calculation multiple times later.

Change-Id: I3b594e01ca50a583f45174e69a24f0b0eca32dde
Signed-off-by: default avatarAmir Vajid <avajid@codeaurora.org>
[avajid@codeaurora.org: made minor styling changes]
Signed-off-by: default avatarAmir Vajid <avajid@codeaurora.org>
parent 74b58a68

drivers/devfreq/arm-memlat-mon.c

+38 −36
Original line number Diff line number Diff line
@@ -49,6 +49,12 @@ struct event_data { 
	unsigned long		last_delta;

};



struct cpu_data {

	struct event_data	common_evs[NUM_COMMON_EVS];

	unsigned long		freq;

	unsigned long		stall_pct;

};



/**

 * struct memlat_mon - A specific consumer of cpu_grp generic counters.

 *
@@ -85,8 +91,9 @@ struct memlat_mon { 
 *

 * @cpus:			The CPUs this cpu_grp will read events from.

 * @common_ev_ids:		The event codes of the events all mons need.

 * @common_evs:			The event data of the events all mons need.

 *				Organized as a 2d array of [cpu][event].

 * @cpus_data:			The cpus data array of length #cpus. Includes

 *				event_data of all the events all mons need as

 *				well as common computed cpu data like freq.

 * @last_update_ts:		Used to avoid redundant reads.

 * @last_ts_delta_us:		The time difference between the most recent

 *				update and the one before that. Used to compute
@@ -104,7 +111,7 @@ struct memlat_mon { 
struct memlat_cpu_grp {

	cpumask_t		cpus;

	unsigned int		common_ev_ids[NUM_COMMON_EVS];

	struct event_data	**common_evs;

	struct cpu_data		*cpus_data;

	ktime_t			last_update_ts;

	unsigned long		last_ts_delta_us;
@@ -122,8 +129,10 @@ struct memlat_mon_spec { 
	enum mon_type type;

};



#define to_common_cpustats(cpu_grp, cpu) \

	(cpu_grp->common_evs[cpu - cpumask_first(&cpu_grp->cpus)])

#define to_cpu_data(cpu_grp, cpu) \

	(&cpu_grp->cpus_data[cpu - cpumask_first(&cpu_grp->cpus)])

#define to_common_evs(cpu_grp, cpu) \

	(cpu_grp->cpus_data[cpu - cpumask_first(&cpu_grp->cpus)].common_evs)

#define to_devstats(mon, cpu) \

	(&mon->hw.core_stats[cpu - cpumask_first(&mon->cpus)])

#define to_mon(hwmon) container_of(hwmon, struct memlat_mon, hw)
@@ -156,15 +165,20 @@ static void update_counts(struct memlat_cpu_grp *cpu_grp) 
	cpu_grp->last_update_ts = now;



	for_each_cpu(cpu, &cpu_grp->cpus) {

		struct event_data *cpu_grp_stats =

			to_common_cpustats(cpu_grp, cpu);

		struct cpu_data *cpu_data = to_cpu_data(cpu_grp, cpu);

		struct event_data *common_evs = cpu_data->common_evs;



		for (i = 0; i < NUM_COMMON_EVS; i++)

			read_event(&cpu_grp_stats[i]);

			read_event(&common_evs[i]);



		if (!cpu_grp_stats[STALL_IDX].pevent)

			cpu_grp_stats[STALL_IDX].last_delta =

				cpu_grp_stats[CYC_IDX].last_delta;

		if (!common_evs[STALL_IDX].pevent)

			common_evs[STALL_IDX].last_delta =

				common_evs[CYC_IDX].last_delta;



		cpu_data->freq = common_evs[CYC_IDX].last_delta / delta;

		cpu_data->stall_pct = mult_frac(100,

				common_evs[STALL_IDX].last_delta,

				common_evs[CYC_IDX].last_delta);

	}



	for (i = 0; i < cpu_grp->num_mons; i++) {
@@ -188,18 +202,15 @@ static unsigned long get_cnt(struct memlat_hwmon *hw) 
	unsigned int cpu;



	for_each_cpu(cpu, &mon->cpus) {

		struct event_data *cpu_grp_stats =

			to_common_cpustats(cpu_grp, cpu);

		struct cpu_data *cpu_data = to_cpu_data(cpu_grp, cpu);

		struct event_data *common_evs = cpu_data->common_evs;

		unsigned int mon_idx =

			cpu - cpumask_first(&mon->cpus);

		struct dev_stats *devstats = to_devstats(mon, cpu);



		devstats->freq = cpu_grp_stats[CYC_IDX].last_delta /

			cpu_grp->last_ts_delta_us;

		devstats->stall_pct =

			mult_frac(100, cpu_grp_stats[STALL_IDX].last_delta,

				  cpu_grp_stats[CYC_IDX].last_delta);

		devstats->inst_count = cpu_grp_stats[INST_IDX].last_delta;

		devstats->freq = cpu_data->freq;

		devstats->stall_pct = cpu_data->stall_pct;

		devstats->inst_count = common_evs[INST_IDX].last_delta;



		if (mon->miss_ev)

			devstats->mem_count =
@@ -263,10 +274,10 @@ static int init_common_evs(struct memlat_cpu_grp *cpu_grp, 
	int ret = 0;



	for_each_cpu(cpu, &cpu_grp->cpus) {

		struct event_data *cpustats = to_common_cpustats(cpu_grp, cpu);

		struct event_data *common_evs = to_common_evs(cpu_grp, cpu);



		for (i = 0; i < NUM_COMMON_EVS; i++) {

			ret = set_event(&cpustats[i], cpu,

			ret = set_event(&common_evs[i], cpu,

					cpu_grp->common_ev_ids[i], attr);

			if (ret < 0)

				break;
@@ -281,10 +292,10 @@ static void free_common_evs(struct memlat_cpu_grp *cpu_grp) 
	unsigned int cpu, i;



	for_each_cpu(cpu, &cpu_grp->cpus) {

		struct event_data *cpustats = to_common_cpustats(cpu_grp, cpu);

		struct event_data *common_evs = to_common_evs(cpu_grp, cpu);



		for (i = 0; i < NUM_COMMON_EVS; i++)

			delete_event(&cpustats[i]);

			delete_event(&common_evs[i]);

	}

}
@@ -497,7 +508,7 @@ static int memlat_cpu_grp_probe(struct platform_device *pdev) 
	struct device *dev = &pdev->dev;

	struct memlat_cpu_grp *cpu_grp;

	int ret = 0;

	unsigned int i, event_id, num_cpus, num_mons;

	unsigned int event_id, num_cpus, num_mons;



	cpu_grp = devm_kzalloc(dev, sizeof(*cpu_grp), GFP_KERNEL);

	if (!cpu_grp)
@@ -547,21 +558,12 @@ static int memlat_cpu_grp_probe(struct platform_device *pdev) 
		cpu_grp->common_ev_ids[STALL_IDX] = event_id;



	num_cpus = cpumask_weight(&cpu_grp->cpus);

	cpu_grp->common_evs =

		devm_kzalloc(dev, num_cpus * sizeof(*cpu_grp->common_evs),

	cpu_grp->cpus_data =

		devm_kzalloc(dev, num_cpus * sizeof(*cpu_grp->cpus_data),

			     GFP_KERNEL);

	if (!cpu_grp->common_evs)

	if (!cpu_grp->cpus_data)

		return -ENOMEM;



	for (i = 0; i < num_cpus; i++) {

		cpu_grp->common_evs[i] =

			devm_kzalloc(dev, NUM_COMMON_EVS *

				     sizeof(*cpu_grp->common_evs[i]),

				     GFP_KERNEL);

		if (!cpu_grp->common_evs[i])

			return -ENOMEM;

	}



	mutex_init(&cpu_grp->mons_lock);

	cpu_grp->update_ms = DEFAULT_UPDATE_MS;