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Date: Thu, 4 Sep 2014 20:30:57 +0400
From: klamm@...dex-team.ru
To: peterz@...radead.org, mingo@...hat.com,
linux-kernel@...r.kernel.org
Cc: stfomichev@...dex-team.ru, Roman Gushchin <klamm@...dex-team.ru>
Subject: [PATCH 11/19] smart: smart debug
From: Roman Gushchin <klamm@...dex-team.ru>
This patch introduces debug infrastructure for smart.
The infrastructure contains a number of per-cpu counters,
smart_event() function to register smart-related events and procfs
interface to read and reset these counters.
The following events are counting:
pull - smart pull
balance_local - local cpu selection
balance_remote - remote cpu selection
select_core - free local core selected
select_rcore - free remote core selected
select_thread - free local cpu selected
select_rthread - free remote cpu selected
select_busy - busy cpu selected
select_busy_curr - current busy cpu selected
select_fallback - select_fallback_rq() called
rt_pull - rt push
rt_push - rt pull
Signed-off-by: Roman Gushchin <klamm@...dex-team.ru>
---
init/Kconfig | 8 +++++
kernel/sched/core.c | 3 ++
kernel/sched/rt.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++-
kernel/sched/sched.h | 38 +++++++++++++++++++++++
4 files changed, 133 insertions(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig
index 98dd173..d936b49 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -813,6 +813,14 @@ config SMART
enabled hyper-threading.
Do not use for hard real-time purposes.
+config SMART_DEBUG
+ bool "Enable SMART debug features"
+ default y
+ depends on SMART
+ help
+ This option adds gathering of SMART statistics. It's
+ available via /proc/smart_stat interface.
+
menuconfig CGROUPS
boolean "Control Group support"
depends on EVENTFD
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5954f48..c2b988c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1180,6 +1180,9 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
enum { cpuset, possible, fail } state = cpuset;
int dest_cpu;
+ if (smart_enabled() && task_has_rt_policy(p))
+ smart_event(select_fallback);
+
/*
* If the node that the cpu is on has been offlined, cpu_to_node()
* will return -1. There is no cpu on the node, and we should
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 8621443..14acd51 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -9,8 +9,69 @@
#ifdef CONFIG_SMART
#include <linux/workqueue.h>
+#include <linux/proc_fs.h>
+
+#ifdef CONFIG_SMART_DEBUG
+#include <linux/seq_file.h>
#include <linux/jump_label.h>
+DEFINE_PER_CPU(struct smart_stat, smart_stat);
+
+static struct proc_dir_entry *smart_pde;
+
+static ssize_t smart_proc_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ int c;
+
+ for_each_possible_cpu(c)
+ memset(&per_cpu(smart_stat, c), 0, sizeof(struct smart_stat));
+
+ return count;
+}
+
+#define smart_stat_print(m, field) \
+ ({ \
+ u64 res = 0; \
+ unsigned int c; \
+ for_each_possible_cpu(c) \
+ res += per_cpu(smart_stat, c).field; \
+ seq_printf(m, "%-16s %llu\n", #field, res); \
+ })
+
+static int smart_proc_show(struct seq_file *m, void *arg)
+{
+ smart_stat_print(m, pull);
+ smart_stat_print(m, balance_local);
+ smart_stat_print(m, balance_remote);
+ smart_stat_print(m, select_core);
+ smart_stat_print(m, select_rcore);
+ smart_stat_print(m, select_thread);
+ smart_stat_print(m, select_rthread);
+ smart_stat_print(m, select_busy);
+ smart_stat_print(m, select_busy_curr);
+ smart_stat_print(m, select_fallback);
+ smart_stat_print(m, rt_pull);
+ smart_stat_print(m, rt_push);
+
+ return 0;
+}
+
+static int smart_proc_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, smart_proc_show, NULL);
+}
+
+static const struct file_operations smart_proc_fops = {
+ .owner = THIS_MODULE,
+ .open = smart_proc_open,
+ .read = seq_read,
+ .write = smart_proc_write,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+#endif
+
struct static_key __smart_initialized = STATIC_KEY_INIT_FALSE;
struct static_key __smart_enabled = STATIC_KEY_INIT_TRUE;
DEFINE_MUTEX(smart_mutex);
@@ -1773,6 +1834,9 @@ retry:
out:
put_task_struct(next_task);
+ if (ret)
+ smart_event(rt_push);
+
return ret;
}
@@ -1859,6 +1923,9 @@ skip:
double_unlock_balance(this_rq, src_rq);
}
+ if (ret)
+ smart_event(rt_pull);
+
return ret;
}
@@ -2270,6 +2337,13 @@ void build_smart_topology(void)
if (was_initialized)
printk(KERN_INFO "smart: disabled\n");
+#ifdef CONFIG_SMART_DEBUG
+ if (!smart_pde)
+ smart_pde = proc_create("smart_stat",
+ S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH,
+ NULL, &smart_proc_fops);
+#endif
+
get_online_cpus();
for_each_online_cpu(cpu) {
/* __cpu_core_id */
@@ -2369,6 +2443,9 @@ static int smart_find_lowest_rq(struct task_struct *task, bool wakeup)
prev_cpu = core_node_sibling(prev_cpu);
}
}
+
+ smart_event_node(task_cpu(task), prev_cpu,
+ balance_local, balance_remote);
}
for (attempts = 3; attempts; attempts--) {
@@ -2376,14 +2453,20 @@ static int smart_find_lowest_rq(struct task_struct *task, bool wakeup)
if (best_cpu == -1) {
best_cpu = find_rt_best_thread(prev_cpu, task);
+ smart_event_node(task_cpu(task), best_cpu,
+ select_thread, select_rthread);
+
break;
}
if (!acquire_core(best_cpu))
continue;
- if (likely(core_is_rt_free(best_cpu)))
+ if (likely(core_is_rt_free(best_cpu))) {
+ smart_event_node(task_cpu(task), best_cpu,
+ select_core, select_rcore);
break;
+ }
release_core(best_cpu);
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 80d202e..d450b8f 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1380,6 +1380,38 @@ static inline u64 irq_time_read(int cpu)
#endif /* CONFIG_64BIT */
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+#ifdef CONFIG_SMART_DEBUG
+struct smart_stat {
+ u64 pull;
+ u64 balance_local;
+ u64 balance_remote;
+ u64 select_core;
+ u64 select_rcore;
+ u64 select_thread;
+ u64 select_rthread;
+ u64 select_busy;
+ u64 select_busy_curr;
+ u64 select_fallback;
+ u64 rt_pull;
+ u64 rt_push;
+};
+
+DECLARE_PER_CPU(struct smart_stat, smart_stat);
+#define smart_event(e) do { __get_cpu_var(smart_stat).e++; } while (0)
+#define smart_event_node(prev_cpu, next_cpu, local_event, remote_event) \
+ do { \
+ if (prev_cpu >= 0 && next_cpu >= 0 && \
+ cpu_to_node(prev_cpu) == cpu_to_node(next_cpu)) \
+ smart_event(local_event); \
+ else \
+ smart_event(remote_event); \
+ } while (0)
+#else
+#define smart_event(e) do { } while (0)
+#define smart_event_node(prev_cpu, next_cpu, local_event, remote_event) \
+ do { } while (0)
+#endif /* CONFIG_SMART_DEBUG */
+
#ifdef CONFIG_SMART
struct smart_core_data {
int cpu_core_id;
@@ -1417,6 +1449,7 @@ static inline int cpu_core_id(int cpu)
#define smart_data(cpu) per_cpu(smart_core_data, cpu_core_id(cpu))
#define smart_node_ptr(cpu) smart_node_data[cpu_to_node(cpu)]
#define smart_gathering_data(cpu) per_cpu(smart_gathering_data, cpu)
+#define smart_stats(cpu) per_cpu(smart_core_data, cpu_core_id(cpu)).stats
static inline bool smart_enabled(void)
{
@@ -1587,6 +1620,11 @@ static inline int find_rt_best_thread(int start_cpu, struct task_struct *task)
min_running == cpu_rq(start_cpu)->rt.rt_nr_running)
best_cpu = -1;
+ if (best_cpu == -1 || best_cpu == start_cpu)
+ smart_event(select_busy_curr);
+ else
+ smart_event(select_busy);
+
return best_cpu;
}
--
1.9.3
--
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