PM / EM: Expose the Energy Model in debugfs (9cac42d0) · Commits · 戴 / test

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 Signed-off-by:

Quentin Perret <quentin.perret@arm.com> Reviewed-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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:

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