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Commit 5f5a5775 authored by Quentin Perret's avatar Quentin Perret
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FROMGIT: PM / EM: Expose the Energy Model in debugfs 



The recently introduced Energy Model (EM) framework manages power cost
tables of CPUs. These tables are currently only visible from kernel
space. However, in order to debug the behaviour of subsystems that use
the EM (EAS for example), it is often required to know what the power
costs are from userspace.

For this reason, introduce under /sys/kernel/debug/energy_model a set of
directories representing the performance domains of the system. Each
performance domain contains a set of sub-directories representing the
different capacity states (cs) and their attributes, as well as a file
exposing the related CPUs.

The resulting hierarchy is as follows on Arm juno r0 for example:

    /sys/kernel/debug/energy_model
    ├── pd0
    │   ├── cpus
    │   ├── cs:450000
    │   │   ├── cost
    │   │   ├── frequency
    │   │   └── power
    │   ├── cs:575000
    │   │   ├── cost
    │   │   ├── frequency
    │   │   └── power
    │   ├── cs:700000
    │   │   ├── cost
    │   │   ├── frequency
    │   │   └── power
    │   ├── cs:775000
    │   │   ├── cost
    │   │   ├── frequency
    │   │   └── power
    │   └── cs:850000
    │       ├── cost
    │       ├── frequency
    │       └── power
    └── pd1
        ├── cpus
        ├── cs:1100000
        │   ├── cost
        │   ├── frequency
        │   └── power
        ├── cs:450000
        │   ├── cost
        │   ├── frequency
        │   └── power
        ├── cs:625000
        │   ├── cost
        │   ├── frequency
        │   └── power
        ├── cs:800000
        │   ├── cost
        │   ├── frequency
        │   └── power
        └── cs:950000
            ├── cost
            ├── frequency
            └── power

Bug: 120440300
Change-Id: I4098c3d3e07fc4a14514751ac881422131b759e9
Signed-off-by: default avatarQuentin Perret <quentin.perret@arm.com>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 9cac42d0645ceb2ca8b815cee04810ec9b0d13b3
 git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git

 bleeding-edge)
Signed-off-by: default avatarQuentin Perret <quentin.perret@arm.com>
parent 26bf8166

kernel/power/energy_model.c

+57 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 


#include <linux/cpu.h>

#include <linux/cpumask.h>

#include <linux/debugfs.h>

#include <linux/energy_model.h>

#include <linux/sched/topology.h>

#include <linux/slab.h>
@@ -23,6 +24,60 @@ static DEFINE_PER_CPU(struct em_perf_domain *, em_data); 
 */

static DEFINE_MUTEX(em_pd_mutex);



#ifdef CONFIG_DEBUG_FS

static struct dentry *rootdir;



static void em_debug_create_cs(struct em_cap_state *cs, struct dentry *pd)

{

	struct dentry *d;

	char name[24];



	snprintf(name, sizeof(name), "cs:%lu", cs->frequency);



	/* Create per-cs directory */

	d = debugfs_create_dir(name, pd);

	debugfs_create_ulong("frequency", 0444, d, &cs->frequency);

	debugfs_create_ulong("power", 0444, d, &cs->power);

	debugfs_create_ulong("cost", 0444, d, &cs->cost);

}



static int em_debug_cpus_show(struct seq_file *s, void *unused)

{

	seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));



	return 0;

}

DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);



static void em_debug_create_pd(struct em_perf_domain *pd, int cpu)

{

	struct dentry *d;

	char name[8];

	int i;



	snprintf(name, sizeof(name), "pd%d", cpu);



	/* Create the directory of the performance domain */

	d = debugfs_create_dir(name, rootdir);



	debugfs_create_file("cpus", 0444, d, pd->cpus, &em_debug_cpus_fops);



	/* Create a sub-directory for each capacity state */

	for (i = 0; i < pd->nr_cap_states; i++)

		em_debug_create_cs(&pd->table[i], d);

}



static int __init em_debug_init(void)

{

	/* Create /sys/kernel/debug/energy_model directory */

	rootdir = debugfs_create_dir("energy_model", NULL);



	return 0;

}

core_initcall(em_debug_init);

#else /* CONFIG_DEBUG_FS */

static void em_debug_create_pd(struct em_perf_domain *pd, int cpu) {}

#endif

static struct em_perf_domain *em_create_pd(cpumask_t *span, int nr_states,

						struct em_data_callback *cb)

{
@@ -102,6 +157,8 @@ static struct em_perf_domain *em_create_pd(cpumask_t *span, int nr_states, 
	pd->nr_cap_states = nr_states;

	cpumask_copy(to_cpumask(pd->cpus), span);



	em_debug_create_pd(pd, cpu);



	return pd;



free_cs_table: