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Commit 43ae34cb authored by Ingo Molnar's avatar Ingo Molnar
Browse files

sched: scheduler debugging, core 



scheduler debugging core: implement /proc/sched_debug and
/proc/<PID>/sched files for scheduler debugging.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 77e54a1f

fs/proc/base.c

+69 −0
Original line number Diff line number Diff line
@@ -929,6 +929,69 @@ static const struct file_operations proc_fault_inject_operations = { 
};

#endif



#ifdef CONFIG_SCHED_DEBUG

/*

 * Print out various scheduling related per-task fields:

 */

static int sched_show(struct seq_file *m, void *v)

{

	struct inode *inode = m->private;

	struct task_struct *p;



	WARN_ON(!inode);



	p = get_proc_task(inode);

	if (!p)

		return -ESRCH;

	proc_sched_show_task(p, m);



	put_task_struct(p);



	return 0;

}



static ssize_t

sched_write(struct file *file, const char __user *buf,

	    size_t count, loff_t *offset)

{

	struct inode *inode = file->f_path.dentry->d_inode;

	struct task_struct *p;



	WARN_ON(!inode);



	p = get_proc_task(inode);

	if (!p)

		return -ESRCH;

	proc_sched_set_task(p);



	put_task_struct(p);



	return count;

}



static int sched_open(struct inode *inode, struct file *filp)

{

	int ret;



	ret = single_open(filp, sched_show, NULL);

	if (!ret) {

		struct seq_file *m = filp->private_data;



		m->private = inode;

	}

	return ret;

}



static const struct file_operations proc_pid_sched_operations = {

	.open		= sched_open,

	.read		= seq_read,

	.write		= sched_write,

	.llseek		= seq_lseek,

	.release	= seq_release,

};



#endif



static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)

{

	struct inode *inode = dentry->d_inode;
@@ -1963,6 +2026,9 @@ static const struct pid_entry tgid_base_stuff[] = { 
	INF("environ",    S_IRUSR, pid_environ),

	INF("auxv",       S_IRUSR, pid_auxv),

	INF("status",     S_IRUGO, pid_status),

#ifdef CONFIG_SCHED_DEBUG

	REG("sched",      S_IRUGO|S_IWUSR, pid_sched),

#endif

	INF("cmdline",    S_IRUGO, pid_cmdline),

	INF("stat",       S_IRUGO, tgid_stat),

	INF("statm",      S_IRUGO, pid_statm),
@@ -2247,6 +2313,9 @@ static const struct pid_entry tid_base_stuff[] = { 
	INF("environ",   S_IRUSR, pid_environ),

	INF("auxv",      S_IRUSR, pid_auxv),

	INF("status",    S_IRUGO, pid_status),

#ifdef CONFIG_SCHED_DEBUG

	REG("sched",     S_IRUGO|S_IWUSR, pid_sched),

#endif

	INF("cmdline",   S_IRUGO, pid_cmdline),

	INF("stat",      S_IRUGO, tid_stat),

	INF("statm",     S_IRUGO, pid_statm),

include/linux/sched.h

+20 −0
Original line number Diff line number Diff line
@@ -132,6 +132,26 @@ extern unsigned long nr_active(void); 
extern unsigned long nr_iowait(void);

extern unsigned long weighted_cpuload(const int cpu);



struct seq_file;

struct cfs_rq;

#ifdef CONFIG_SCHED_DEBUG

extern void proc_sched_show_task(struct task_struct *p, struct seq_file *m);

extern void proc_sched_set_task(struct task_struct *p);

extern void

print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq, u64 now);

#else

static inline void

proc_sched_show_task(struct task_struct *p, struct seq_file *m)

{

}

static inline void proc_sched_set_task(struct task_struct *p)

{

}

static inline void

print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq, u64 now)

{

}

#endif



/*

 * Task state bitmask. NOTE! These bits are also

kernel/sched_debug.c

0 → 100644
+275 −0
Original line number Diff line number Diff line 
/*

 * kernel/time/sched_debug.c

 *

 * Print the CFS rbtree

 *

 * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#include <linux/proc_fs.h>

#include <linux/sched.h>

#include <linux/seq_file.h>

#include <linux/kallsyms.h>

#include <linux/utsname.h>



/*

 * This allows printing both to /proc/sched_debug and

 * to the console

 */

#define SEQ_printf(m, x...)			\

 do {						\

	if (m)					\

		seq_printf(m, x);		\

	else					\

		printk(x);			\

 } while (0)



static void

print_task(struct seq_file *m, struct rq *rq, struct task_struct *p, u64 now)

{

	if (rq->curr == p)

		SEQ_printf(m, "R");

	else

		SEQ_printf(m, " ");



	SEQ_printf(m, "%15s %5d %15Ld %13Ld %13Ld %9Ld %5d "

		      "%15Ld %15Ld %15Ld %15Ld %15Ld\n",

		p->comm, p->pid,

		(long long)p->se.fair_key,

		(long long)(p->se.fair_key - rq->cfs.fair_clock),

		(long long)p->se.wait_runtime,

		(long long)(p->nvcsw + p->nivcsw),

		p->prio,

		(long long)p->se.sum_exec_runtime,

		(long long)p->se.sum_wait_runtime,

		(long long)p->se.sum_sleep_runtime,

		(long long)p->se.wait_runtime_overruns,

		(long long)p->se.wait_runtime_underruns);

}



static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu, u64 now)

{

	struct task_struct *g, *p;



	SEQ_printf(m,

	"\nrunnable tasks:\n"

	"            task   PID        tree-key         delta       waiting"

	"  switches  prio"

	"        sum-exec        sum-wait       sum-sleep"

	"    wait-overrun   wait-underrun\n"

	"------------------------------------------------------------------"

	"----------------"

	"------------------------------------------------"

	"--------------------------------\n");



	read_lock_irq(&tasklist_lock);



	do_each_thread(g, p) {

		if (!p->se.on_rq || task_cpu(p) != rq_cpu)

			continue;



		print_task(m, rq, p, now);

	} while_each_thread(g, p);



	read_unlock_irq(&tasklist_lock);

}



static void

print_cfs_rq_runtime_sum(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)

{

	s64 wait_runtime_rq_sum = 0;

	struct task_struct *p;

	struct rb_node *curr;

	unsigned long flags;

	struct rq *rq = &per_cpu(runqueues, cpu);



	spin_lock_irqsave(&rq->lock, flags);

	curr = first_fair(cfs_rq);

	while (curr) {

		p = rb_entry(curr, struct task_struct, se.run_node);

		wait_runtime_rq_sum += p->se.wait_runtime;



		curr = rb_next(curr);

	}

	spin_unlock_irqrestore(&rq->lock, flags);



	SEQ_printf(m, "  .%-30s: %Ld\n", "wait_runtime_rq_sum",

		(long long)wait_runtime_rq_sum);

}



void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq, u64 now)

{

	SEQ_printf(m, "\ncfs_rq %p\n", cfs_rq);



#define P(x) \

	SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(cfs_rq->x))



	P(fair_clock);

	P(exec_clock);

	P(wait_runtime);

	P(wait_runtime_overruns);

	P(wait_runtime_underruns);

	P(sleeper_bonus);

#undef P



	print_cfs_rq_runtime_sum(m, cpu, cfs_rq);

}



static void print_cpu(struct seq_file *m, int cpu, u64 now)

{

	struct rq *rq = &per_cpu(runqueues, cpu);



#ifdef CONFIG_X86

	{

		unsigned int freq = cpu_khz ? : 1;



		SEQ_printf(m, "\ncpu#%d, %u.%03u MHz\n",

			   cpu, freq / 1000, (freq % 1000));

	}

#else

	SEQ_printf(m, "\ncpu#%d\n", cpu);

#endif



#define P(x) \

	SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x))



	P(nr_running);

	SEQ_printf(m, "  .%-30s: %lu\n", "load",

		   rq->ls.load.weight);

	P(ls.delta_fair);

	P(ls.delta_exec);

	P(nr_switches);

	P(nr_load_updates);

	P(nr_uninterruptible);

	SEQ_printf(m, "  .%-30s: %lu\n", "jiffies", jiffies);

	P(next_balance);

	P(curr->pid);

	P(clock);

	P(prev_clock_raw);

	P(clock_warps);

	P(clock_overflows);

	P(clock_unstable_events);

	P(clock_max_delta);

	P(cpu_load[0]);

	P(cpu_load[1]);

	P(cpu_load[2]);

	P(cpu_load[3]);

	P(cpu_load[4]);

#undef P



	print_cfs_stats(m, cpu, now);



	print_rq(m, rq, cpu, now);

}



static int sched_debug_show(struct seq_file *m, void *v)

{

	u64 now = ktime_to_ns(ktime_get());

	int cpu;



	SEQ_printf(m, "Sched Debug Version: v0.04, cfs-v20, %s %.*s\n",

		init_utsname()->release,

		(int)strcspn(init_utsname()->version, " "),

		init_utsname()->version);



	SEQ_printf(m, "now at %Lu nsecs\n", (unsigned long long)now);



	for_each_online_cpu(cpu)

		print_cpu(m, cpu, now);



	SEQ_printf(m, "\n");



	return 0;

}



void sysrq_sched_debug_show(void)

{

	sched_debug_show(NULL, NULL);

}



static int sched_debug_open(struct inode *inode, struct file *filp)

{

	return single_open(filp, sched_debug_show, NULL);

}



static struct file_operations sched_debug_fops = {

	.open		= sched_debug_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= seq_release,

};



static int __init init_sched_debug_procfs(void)

{

	struct proc_dir_entry *pe;



	pe = create_proc_entry("sched_debug", 0644, NULL);

	if (!pe)

		return -ENOMEM;



	pe->proc_fops = &sched_debug_fops;



	return 0;

}



__initcall(init_sched_debug_procfs);



void proc_sched_show_task(struct task_struct *p, struct seq_file *m)

{

	unsigned long flags;

	int num_threads = 1;



	rcu_read_lock();

	if (lock_task_sighand(p, &flags)) {

		num_threads = atomic_read(&p->signal->count);

		unlock_task_sighand(p, &flags);

	}

	rcu_read_unlock();



	SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, p->pid, num_threads);

	SEQ_printf(m, "----------------------------------------------\n");

#define P(F) \

	SEQ_printf(m, "%-25s:%20Ld\n", #F, (long long)p->F)



	P(se.wait_start);

	P(se.wait_start_fair);

	P(se.exec_start);

	P(se.sleep_start);

	P(se.sleep_start_fair);

	P(se.block_start);

	P(se.sleep_max);

	P(se.block_max);

	P(se.exec_max);

	P(se.wait_max);

	P(se.wait_runtime);

	P(se.wait_runtime_overruns);

	P(se.wait_runtime_underruns);

	P(se.sum_wait_runtime);

	P(se.sum_exec_runtime);

	SEQ_printf(m, "%-25s:%20Ld\n",

		   "nr_switches", (long long)(p->nvcsw + p->nivcsw));

	P(se.load.weight);

	P(policy);

	P(prio);

#undef P



	{

		u64 t0, t1;



		t0 = sched_clock();

		t1 = sched_clock();

		SEQ_printf(m, "%-25s:%20Ld\n",

			   "clock-delta", (long long)(t1-t0));

	}

}



void proc_sched_set_task(struct task_struct *p)

{

	p->se.sleep_max = p->se.block_max = p->se.exec_max = p->se.wait_max = 0;

	p->se.wait_runtime_overruns = p->se.wait_runtime_underruns = 0;

	p->se.sum_exec_runtime = 0;

}