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

Signed-off-by: Ingo Molnar <[email protected]>
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Ingo Molnar committed Jul 9, 2007
1 parent 77e54a1 commit 43ae34c
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69 changes: 69 additions & 0 deletions fs/proc/base.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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),
Expand Down Expand Up @@ -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),
Expand Down
20 changes: 20 additions & 0 deletions include/linux/sched.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
275 changes: 275 additions & 0 deletions kernel/sched_debug.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,275 @@
/*
* 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;
}

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