[patch 45/46] Add debugging feature /proc/timer_list

Thomas Gleixner
2007-01-23T22:01:53Z

[-- Attachment #1: debugging-feature-proc-timer_list.patch --]
[-- Type: text/plain, Size: 14502 bytes --]

From: Ingo Molnar <mingo@elte.hu>

add /proc/timer_list, which prints all currently pending (high-res) timers,
all clock-event sources and their parameters in a human-readable form.

Sample output:

Timer List Version: v0.1
HRTIMER_MAX_CLOCK_BASES: 2
now at 4246046273872 nsecs

cpu: 0
clock 0:
.index: 0
.resolution: 1 nsecs
.get_time: ktime_get_real
.offset: 1273998312645738432 nsecs
active timers:
clock 1:
.index: 1
.resolution: 1 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: <f5a90ec8>, hrtimer_sched_tick, hrtimer_stop_sched_tick, swapper/0
# expires at 4246432689566 nsecs [in 386415694 nsecs]
#1: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, pcscd/2050
# expires at 4247018194689 nsecs [in 971920817 nsecs]
#2: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, irqbalance/1909
# expires at 4247351358392 nsecs [in 1305084520 nsecs]
#3: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, crond/2157
# expires at 4249097614968 nsecs [in 3051341096 nsecs]
#4: <f5a90ec8>, it_real_fn, do_setitimer, syslogd/1888
# expires at 4251329900926 nsecs [in 5283627054 nsecs]
.expires_next : 4246432689566 nsecs
.hres_active : 1
.check_clocks : 0
.nr_events : 31306
.idle_tick : 4246020791890 nsecs
.tick_stopped : 1
.idle_jiffies : 986504
.idle_calls : 40700
.idle_sleeps : 36014
.idle_entrytime : 4246019418883 nsecs
.idle_sleeptime : 4178181972709 nsecs

cpu: 1
clock 0:
.index: 0
.resolution: 1 nsecs
.get_time: ktime_get_real
.offset: 1273998312645738432 nsecs
active timers:
clock 1:
.index: 1
.resolution: 1 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: <f5a90ec8>, hrtimer_sched_tick, hrtimer_restart_sched_tick, swapper/0
# expires at 4246050084568 nsecs [in 3810696 nsecs]
#1: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, atd/2227
# expires at 4261010635003 nsecs [in 14964361131 nsecs]
#2: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, smartd/2332
# expires at 5469485798970 nsecs [in 1223439525098 nsecs]
.expires_next : 4246050084568 nsecs
.hres_active : 1
.check_clocks : 0
.nr_events : 24043
.idle_tick : 4246046084568 nsecs
.tick_stopped : 0
.idle_jiffies : 986510
.idle_calls : 26360
.idle_sleeps : 22551
.idle_entrytime : 4246043874339 nsecs
.idle_sleeptime : 4170763761184 nsecs

tick_broadcast_mask: 00000003
event_broadcast_mask: 00000001

CPU#0's local event device:

Clock Event Device: lapic
capabilities: 0000000e
max_delta_ns: 807385544
min_delta_ns: 1443
mult: 44624025
shift: 32
set_next_event: lapic_next_event
set_mode: lapic_timer_setup
event_handler: hrtimer_interrupt
.installed: 1
.expires: 4246432689566 nsecs

CPU#1's local event device:

Clock Event Device: lapic
capabilities: 0000000e
max_delta_ns: 807385544
min_delta_ns: 1443
mult: 44624025
shift: 32
set_next_event: lapic_next_event
set_mode: lapic_timer_setup
event_handler: hrtimer_interrupt
.installed: 1
.expires: 4246050084568 nsecs

Clock Event Device: hpet
capabilities: 00000007
max_delta_ns: 2147483647
min_delta_ns: 3352
mult: 61496110
shift: 32
set_next_event: hpet_next_event
set_mode: hpet_set_mode
event_handler: handle_nextevt_broadcast

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

include/linux/tick.h | 11 +
kernel/time/Makefile | 2
kernel/time/tick-broadcast.c | 23 +++
kernel/time/tick-common.c | 8 +
kernel/time/timer_list.c | 287 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 329 insertions(+), 2 deletions(-)

Index: linux-2.6.20-rc4-mm1-bo/kernel/time/Makefile
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/kernel/time/Makefile
+++ linux-2.6.20-rc4-mm1-bo/kernel/time/Makefile
@@ -1,4 +1,4 @@
-obj-y += ntp.o clocksource.o jiffies.o
+obj-y += ntp.o clocksource.o jiffies.o timer_list.o

obj-$(CONFIG_GENERIC_CLOCKEVENTS) += clockevents.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o
Index: linux-2.6.20-rc4-mm1-bo/kernel/time/timer_list.c
===================================================================
--- /dev/null
+++ linux-2.6.20-rc4-mm1-bo/kernel/time/timer_list.c
@@ -0,0 +1,287 @@
+/*
+ * kernel/time/timer_list.c
+ *
+ * List pending timers
+ *
+ * Copyright(C) 2006, 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/module.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/tick.h>
+
+#include <asm/uaccess.h>
+
+typedef void (*print_fn_t)(struct seq_file *m, unsigned int *classes);
+
+DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
+
+/*
+ * This allows printing both to /proc/timer_list and
+ * to the console (on SysRq-Q):
+ */
+#define SEQ_printf(m, x...) \
+ do { \
+ if (m) \
+ seq_printf(m, x); \
+ else \
+ printk(x); \
+ } while (0)
+
+static void print_name_offset(struct seq_file *m, void *sym)
+{
+ unsigned long addr = (unsigned long)sym;
+ char namebuf[KSYM_NAME_LEN+1];
+ unsigned long size, offset;
+ const char *sym_name;
+ char *modname;
+
+ sym_name = kallsyms_lookup(addr, &size, &offset, &modname, namebuf);
+ if (sym_name)
+ SEQ_printf(m, "%s", sym_name);
+ else
+ SEQ_printf(m, "<%p>", sym);
+}
+
+static void
+print_timer(struct seq_file *m, struct hrtimer *timer, int idx, u64 now)
+{
+#ifdef CONFIG_TIMER_STATS
+ char tmp[TASK_COMM_LEN + 1];
+#endif
+ SEQ_printf(m, " #%d: ", idx);
+ print_name_offset(m, timer);
+ SEQ_printf(m, ", ");
+ print_name_offset(m, timer->function);
+ SEQ_printf(m, ", S:%02lx", timer->state);
+#ifdef CONFIG_TIMER_STATS
+ SEQ_printf(m, ", ");
+ print_name_offset(m, timer->start_site);
+ memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
+ tmp[TASK_COMM_LEN] = 0;
+ SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
+#endif
+ SEQ_printf(m, "\n");
+ SEQ_printf(m, " # expires at %Ld nsecs [in %Ld nsecs]\n",
+ (unsigned long long)ktime_to_ns(timer->expires),
+ (unsigned long long)(ktime_to_ns(timer->expires) - now));
+}
+
+static void
+print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
+ u64 now)
+{
+ struct hrtimer *timer, tmp;
+ unsigned long next = 0, i;
+ struct rb_node *curr;
+ unsigned long flags;
+
+next_one:
+ i = 0;
+ spin_lock_irqsave(&base->cpu_base->lock, flags);
+
+ curr = base->first;
+ /*
+ * Crude but we have to do this O(N*N) thing, because
+ * we have to unlock the base when printing:
+ */
+ while (curr && i < next) {
+ curr = rb_next(curr);
+ i++;
+ }
+
+ if (curr) {
+
+ timer = rb_entry(curr, struct hrtimer, node);
+ tmp = *timer;
+ spin_unlock_irqrestore(&base->cpu_base->lock, flags);
+
+ print_timer(m, &tmp, i, now);
+ next++;
+ goto next_one;
+ }
+ spin_unlock_irqrestore(&base->cpu_base->lock, flags);
+}
+
+static void
+print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
+{
+ SEQ_printf(m, " .index: %d\n",
+ base->index);
+ SEQ_printf(m, " .resolution: %Ld nsecs\n",
+ (unsigned long long)ktime_to_ns(base->resolution));
+ SEQ_printf(m, " .get_time: ");
+ print_name_offset(m, base->get_time);
+ SEQ_printf(m, "\n");
+#ifdef CONFIG_HIGH_RES_TIMERS
+ SEQ_printf(m, " .offset: %Ld nsecs\n",
+ ktime_to_ns(base->offset));
+#endif
+ SEQ_printf(m, "active timers:\n");
+ print_active_timers(m, base, now);
+}
+
+static void print_cpu(struct seq_file *m, int cpu, u64 now)
+{
+ struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
+ int i;
+
+ SEQ_printf(m, "\ncpu: %d\n", cpu);
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+ SEQ_printf(m, " clock %d:\n", i);
+ print_base(m, cpu_base->clock_base + i, now);
+ }
+#define P(x) \
+ SEQ_printf(m, " .%-15s: %Ld\n", #x, (u64)(cpu_base->x))
+#define P_ns(x) \
+ SEQ_printf(m, " .%-15s: %Ld nsecs\n", #x, \
+ (u64)(ktime_to_ns(cpu_base->x)))
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+ P_ns(expires_next);
+ P(hres_active);
+ P(nr_events);
+#endif
+#undef P
+#undef P_ns
+
+#ifdef CONFIG_TICK_ONESHOT
+# define P(x) \
+ SEQ_printf(m, " .%-15s: %Ld\n", #x, (u64)(ts->x))
+# define P_ns(x) \
+ SEQ_printf(m, " .%-15s: %Ld nsecs\n", #x, \
+ (u64)(ktime_to_ns(ts->x)))
+ {
+ struct tick_sched *ts = tick_get_tick_sched(cpu);
+ P(nohz_mode);
+ P_ns(idle_tick);
+ P(tick_stopped);
+ P(idle_jiffies);
+ P(idle_calls);
+ P(idle_sleeps);
+ P_ns(idle_entrytime);
+ P_ns(idle_sleeptime);
+ P(last_jiffies);
+ P(next_jiffies);
+ P_ns(idle_expires);
+ SEQ_printf(m, "jiffies: %Ld\n", (u64)jiffies);
+ }
+#endif
+
+#undef P
+#undef P_ns
+}
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+static void
+print_tickdevice(struct seq_file *m, struct tick_device *td)
+{
+ struct clock_event_device *dev = td->evtdev;
+
+ SEQ_printf(m, "\nTick Device: mode: %d\n", td->mode);
+
+ SEQ_printf(m, "Clock Event Device: ");
+ if (!dev) {
+ SEQ_printf(m, "<NULL>\n");
+ return;
+ }
+ SEQ_printf(m, "%s\n", dev->name);
+ SEQ_printf(m, " max_delta_ns: %ld\n", dev->max_delta_ns);
+ SEQ_printf(m, " min_delta_ns: %ld\n", dev->min_delta_ns);
+ SEQ_printf(m, " mult: %ld\n", dev->mult);
+ SEQ_printf(m, " shift: %d\n", dev->shift);
+ SEQ_printf(m, " mode: %d\n", dev->mode);
+ SEQ_printf(m, " next_event: %Ld nsecs\n",
+ (unsigned long long) ktime_to_ns(dev->next_event));
+
+ SEQ_printf(m, " set_next_event: ");
+ print_name_offset(m, dev->set_next_event);
+ SEQ_printf(m, "\n");
+
+ SEQ_printf(m, " set_mode: ");
+ print_name_offset(m, dev->set_mode);
+ SEQ_printf(m, "\n");
+
+ SEQ_printf(m, " event_handler: ");
+ print_name_offset(m, dev->event_handler);
+ SEQ_printf(m, "\n");
+}
+
+static void timer_list_show_tickdevices(struct seq_file *m)
+{
+ int cpu;
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+ print_tickdevice(m, tick_get_broadcast_device());
+ SEQ_printf(m, "tick_broadcast_mask: %08lx\n",
+ tick_get_broadcast_mask()->bits[0]);
+#ifdef CONFIG_TICK_ONESHOT
+ SEQ_printf(m, "tick_broadcast_oneshot_mask: %08lx\n",
+ tick_get_broadcast_oneshot_mask()->bits[0]);
+#endif
+ SEQ_printf(m, "\n");
+#endif
+ for_each_online_cpu(cpu)
+ print_tickdevice(m, tick_get_device(cpu));
+ SEQ_printf(m, "\n");
+}
+#else
+static void timer_list_show_tickdevices(struct seq_file *m) { }
+#endif
+
+static int timer_list_show(struct seq_file *m, void *v)
+{
+ u64 now = ktime_to_ns(ktime_get());
+ int cpu;
+
+ SEQ_printf(m, "Timer List Version: v0.3\n");
+ SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
+ SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
+
+ for_each_online_cpu(cpu)
+ print_cpu(m, cpu, now);
+
+ SEQ_printf(m, "\n");
+ timer_list_show_tickdevices(m);
+
+ return 0;
+}
+
+void sysrq_timer_list_show(void)
+{
+ timer_list_show(NULL, NULL);
+}
+
+static int timer_list_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, timer_list_show, NULL);
+}
+
+static struct file_operations timer_list_fops = {
+ .open = timer_list_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static int __init init_timer_list_procfs(void)
+{
+ struct proc_dir_entry *pe;
+
+ pe = create_proc_entry("timer_list", 0644, NULL);
+ if (!pe)
+ return -ENOMEM;
+
+ pe->proc_fops = &timer_list_fops;
+
+ return 0;
+}
+__initcall(init_timer_list_procfs);
Index: linux-2.6.20-rc4-mm1-bo/include/linux/tick.h
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/include/linux/tick.h
+++ linux-2.6.20-rc4-mm1-bo/include/linux/tick.h
@@ -59,6 +59,7 @@ struct tick_sched {

extern void __init tick_init(void);
extern int tick_is_oneshot_available(void);
+extern struct tick_device *tick_get_device(int cpu);

# ifdef CONFIG_HIGH_RES_TIMERS
extern int tick_init_highres(void);
@@ -69,6 +70,16 @@ extern void tick_cancel_sched_timer(int
static inline void tick_cancel_sched_timer(int cpu) { }
# endif /* HIGHRES */

+# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+extern struct tick_device *tick_get_broadcast_device(void);
+extern cpumask_t *tick_get_broadcast_mask(void);
+
+# ifdef CONFIG_TICK_ONESHOT
+extern cpumask_t *tick_get_broadcast_oneshot_mask(void);
+# endif
+
+# endif /* BROADCAST */
+
# ifdef CONFIG_TICK_ONESHOT
extern void tick_clock_notify(void);
extern int tick_check_oneshot_change(int allow_nohz);
Index: linux-2.6.20-rc4-mm1-bo/kernel/time/tick-broadcast.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/kernel/time/tick-broadcast.c
+++ linux-2.6.20-rc4-mm1-bo/kernel/time/tick-broadcast.c
@@ -27,11 +27,24 @@
* timer stops in C3 state.
*/

-static struct tick_device tick_broadcast_device;
+struct tick_device tick_broadcast_device;
static cpumask_t tick_broadcast_mask;
static DEFINE_SPINLOCK(tick_broadcast_lock);

/*
+ * Debugging: see timer_list.c
+ */
+struct tick_device *tick_get_broadcast_device(void)
+{
+ return &tick_broadcast_device;
+}
+
+cpumask_t *tick_get_broadcast_mask(void)
+{
+ return &tick_broadcast_mask;
+}
+
+/*
* Start the device in periodic mode
*/
static void tick_broadcast_start_periodic(struct clock_event_device *bc)
@@ -266,6 +279,14 @@ void tick_do_resume(int cpu)
static cpumask_t tick_broadcast_oneshot_mask;

/*
+ * Debugging: see timer_list.c
+ */
+cpumask_t *tick_get_broadcast_oneshot_mask(void)
+{
+ return &tick_broadcast_oneshot_mask;
+}
+
+/*
* Reprogram the broadcast device:
*
* Called with tick_broadcast_lock held and interrupts disabled.
Index: linux-2.6.20-rc4-mm1-bo/kernel/time/tick-common.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/kernel/time/tick-common.c
+++ linux-2.6.20-rc4-mm1-bo/kernel/time/tick-common.c
@@ -34,6 +34,14 @@ ktime_t tick_period;
static int tick_do_timer_cpu = -1;
DEFINE_SPINLOCK(tick_device_lock);

+/*
+ * Debugging: see timer_list.c
+ */
+struct tick_device *tick_get_device(int cpu)
+{
+ return &per_cpu(tick_cpu_device, cpu);
+}
+
/**
* tick_is_oneshot_available - check for a oneshot capable event device
*/

--