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Steven Rostedt 1b29b01887 ftrace: function tracer 
This is a simple trace that uses the ftrace infrastructure. It is
designed to be fast and small, and easy to use. It is useful to
record things that happen over a very short period of time, and
not to analyze the system in general.

 Updates:

  available_tracers
     "function" is added to this file.

  current_tracer
    To enable the function tracer:

      echo function > /debugfs/tracing/current_tracer

     To disable the tracer:

       echo disable > /debugfs/tracing/current_tracer

The output of the function_trace file is as follows

  "echo noverbose > /debugfs/tracing/iter_ctrl"

preemption latency trace v1.1.5 on 2.6.24-rc7-tst
Signed-off-by: Ingo Molnar <mingo@elte.hu>
--------------------------------------------------------------------
 latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4)
    -----------------
    | task: -0 (uid:0 nice:0 policy:0 rt_prio:0)
    -----------------

                 _------=> CPU#
                / _-----=> irqs-off
               | / _----=> need-resched
               || / _---=> hardirq/softirq
               ||| / _--=> preempt-depth
               |||| /
               |||||     delay
   cmd     pid ||||| time  |   caller
      \   /    |||||   \   |   /
 swapper-0     0d.h. 1595128us+: set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>)
 swapper-0     0d.h. 1595131us+: _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>)

Or with verbose turned on:

  "echo verbose > /debugfs/tracing/iter_ctrl"

preemption latency trace v1.1.5 on 2.6.24-rc7-tst
--------------------------------------------------------------------
 latency: 0 us, #419428/4361791, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4)
    -----------------
    | task: -0 (uid:0 nice:0 policy:0 rt_prio:0)
    -----------------

         swapper     0 0 9 00000000 00000000 [f3675f41] 1595.128ms (+0.003ms): set_normalized_timespec+0x8/0x2d <c043841d> (ktime_get_ts+0x4a/0x4e <c04499d4>)
         swapper     0 0 9 00000000 00000001 [f3675f45] 1595.131ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>)
         swapper     0 0 9 00000000 00000002 [f3675f48] 1595.135ms (+0.003ms): _spin_lock+0x8/0x18 <c0630690> (hrtimer_interrupt+0x6e/0x1b0 <c0449c56>)

The "trace" file is not affected by the verbose mode, but is by the symonly.

 echo "nosymonly" > /debugfs/tracing/iter_ctrl

tracer:
[   81.479967] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <ffffffff80337a4d> <-- _spin_unlock_irqrestore+0xe/0x5a <ffffffff8048cc8f>
[   81.479967] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <ffffffff8048ccbf> <-- sub_preempt_count+0xc/0x7a <ffffffff80233d7b>
[   81.479968] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <ffffffff80233d9f> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d>
[   81.479968] CPU 0: bash:3154 vfs_write+0x11d/0x155 <ffffffff8029a043> <-- dnotify_parent+0x12/0x78 <ffffffff802d54fb>
[   81.479968] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <ffffffff802d5516> <-- _spin_lock+0xe/0x70 <ffffffff8048c910>
[   81.479969] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <ffffffff8048c91d> <-- add_preempt_count+0xe/0x77 <ffffffff80233df7>
[   81.479969] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <ffffffff80233e27> <-- in_lock_functions+0x9/0x24 <ffffffff8025a75d>

 echo "symonly" > /debugfs/tracing/iter_ctrl

tracer:
[   81.479913] CPU 0: bash:3154 register_ftrace_function+0x5f/0x66 <-- _spin_unlock_irqrestore+0xe/0x5a
[   81.479913] CPU 0: bash:3154 _spin_unlock_irqrestore+0x3e/0x5a <-- sub_preempt_count+0xc/0x7a
[   81.479913] CPU 0: bash:3154 sub_preempt_count+0x30/0x7a <-- in_lock_functions+0x9/0x24
[   81.479914] CPU 0: bash:3154 vfs_write+0x11d/0x155 <-- dnotify_parent+0x12/0x78
[   81.479914] CPU 0: bash:3154 dnotify_parent+0x2d/0x78 <-- _spin_lock+0xe/0x70
[   81.479914] CPU 0: bash:3154 _spin_lock+0x1b/0x70 <-- add_preempt_count+0xe/0x77
[   81.479914] CPU 0: bash:3154 add_preempt_count+0x3e/0x77 <-- in_lock_functions+0x9/0x24

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:32:13 +02:00
..
irq genirq: reenable a nobody cared disabled irq when a new driver arrives 2008-05-02 13:40:34 +02:00
power Merge branches 'release', 'acpica', 'bugzilla-10224', 'bugzilla-9772', 'bugzilla-9916', 'ec', 'eeepc', 'idle', 'misc', 'pm-legacy', 'sysfs-links-2.6.26', 'thermal', 'thinkpad' and 'video' into release 2008-04-30 13:58:00 -04:00
time clocksource: allow read access to available/current_clocksource 2008-05-03 18:11:48 +02:00
trace ftrace: function tracer 2008-05-23 20:32:13 +02:00
.gitignore Update kernel/.gitignore with new auto-generated files 2008-02-09 23:27:01 -08:00
acct.c bsd_acct: using task_struct->tgid is not right in pid-namespaces 2008-03-24 19:22:20 -07:00
audit_tree.c [PATCH] list_for_each_rcu must die: audit 2008-05-17 03:30:23 -04:00
audit.c [patch 1/1] audit_send_reply(): fix error-path memory leak 2008-05-17 03:30:22 -04:00
audit.h [PATCH 1/2] audit: move extern declarations to audit.h 2008-04-28 06:28:04 -04:00
auditfilter.c Merge branch 'audit.b50' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current 2008-04-29 11:41:22 -07:00
auditsc.c [PATCH] new predicate - AUDIT_FILETYPE 2008-04-28 06:28:37 -04:00
backtracetest.c x86: add a simple backtrace test module 2008-01-30 13:33:08 +01:00
bounds.c Add kbuild.h that contains common definitions for kbuild users 2008-04-29 08:06:29 -07:00
capability.c Add 64-bit capability support to the kernel 2008-02-05 09:44:20 -08:00
cgroup_debug.c CGroup API files: move "releasable" to cgroup_debug subsystem 2008-04-29 08:06:09 -07:00
cgroup.c mm: bdi: add separate writeback accounting capability 2008-04-30 08:29:50 -07:00
compat.c ntp: support for TAI 2008-05-01 08:03:59 -07:00
configs.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
cpu.c kernel: replace remaining __FUNCTION__ occurrences 2008-04-30 08:29:54 -07:00
cpuset.c Fix cpuset sched_relax_domain_level control file 2008-05-08 10:46:56 -07:00
delayacct.c
dma.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
exec_domain.c
exit.c [PATCH] split linux/file.h 2008-05-01 13:08:16 -04:00
extable.c
fork.c [PATCH] dup_fd() fixes, part 1 2008-05-16 17:22:26 -04:00
futex_compat.c futex_compat __user annotation 2008-03-30 14:18:41 -07:00
futex.c Removal of FUTEX_FD 2008-05-05 08:18:45 -07:00
hrtimer.c hrtimer: remove duplicate helper function 2008-05-03 18:11:48 +02:00
itimer.c ITIMER_REAL: convert to use struct pid 2008-02-08 09:22:29 -08:00
kallsyms.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
Kconfig.hz
Kconfig.preempt rcu: move PREEMPT_RCU config option back under PREEMPT 2008-03-10 18:01:20 -07:00
kexec.c kexec: make extended crashkernel= syntax less confusing 2008-05-01 08:04:00 -07:00
kfifo.c
kgdb.c lib: create common ascii hex array 2008-05-14 19:11:14 -07:00
kmod.c [PATCH] split linux/file.h 2008-05-01 13:08:16 -04:00
kprobes.c kprobes: add (un)register_jprobes for batch registration 2008-04-28 08:58:32 -07:00
ksysfs.c
kthread.c Deprecate find_task_by_pid() 2008-04-30 08:29:48 -07:00
latencytop.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
lockdep_internals.h
lockdep_proc.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
lockdep.c Subject: lockdep: include all lock classes in all_lock_classes 2008-02-25 23:03:02 +01:00
Makefile ftrace: latency tracer infrastructure 2008-05-23 20:32:06 +02:00
marker.c make marker_debug static 2008-04-30 08:29:49 -07:00
module.c module: don't ignore vermagic string if module doesn't have modversions 2008-05-09 07:45:18 -07:00
mutex-debug.c kernel: remove fastcall in kernel/* 2008-02-08 09:22:31 -08:00
mutex-debug.h
mutex.c kernel: remove fastcall in kernel/* 2008-02-08 09:22:31 -08:00
mutex.h
notifier.c ipc: re-enable msgmni automatic recomputing msgmni if set to negative 2008-04-29 08:06:13 -07:00
ns_cgroup.c cgroups: kernel/ns_cgroup.c should #include <linux/nsproxy.h> 2008-04-29 08:06:07 -07:00
nsproxy.c ipc: sysvsem: refuse clone(CLONE_SYSVSEM|CLONE_NEWIPC) 2008-04-29 08:06:14 -07:00
panic.c Taint kernel after WARN_ON(condition) 2008-04-29 08:05:59 -07:00
params.c Add new string functions strict_strto* and convert kernel params to use them 2008-02-08 09:22:41 -08:00
pid_namespace.c pidns: make pid->level and pid_ns->level unsigned 2008-04-30 08:29:49 -07:00
pid.c pids: introduce change_pid() helper 2008-04-30 08:29:48 -07:00
pm_qos_params.c pm qos infrastructure and interface 2008-02-05 09:44:22 -08:00
posix-cpu-timers.c remove div_long_long_rem 2008-05-01 08:03:58 -07:00
posix-timers.c signals: join send_sigqueue() with send_group_sigqueue() 2008-04-30 08:29:36 -07:00
printk.c printk: don't read beyond string arguments' terminating zero 2008-04-30 08:29:52 -07:00
profile.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
ptrace.c make generic sys_ptrace unconditional 2008-05-01 10:21:54 -07:00
rcuclassic.c
rcupdate.c rcupdate: fix comment 2008-02-13 16:21:18 -08:00
rcupreempt_trace.c
rcupreempt.c generic: reduce stack pressure in sched_affinity 2008-04-19 19:44:59 +02:00
rcutorture.c kernel: explicitly include required header files under kernel/ 2008-04-29 08:06:04 -07:00
relay.c Revert "relay: fix splice problem" 2008-05-08 14:06:19 +02:00
res_counter.c memcgroup: add the max_usage member on the res_counter 2008-04-29 08:06:10 -07:00
resource.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
rtmutex_common.h Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
rtmutex-debug.c Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c hrtimer: more hrtimer_init_sleeper() fallout. 2008-02-13 15:45:36 +01:00
rtmutex.h
rwsem.c
sched_clock.c sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK 2008-05-05 23:56:18 +02:00
sched_debug.c sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK 2008-05-05 23:56:18 +02:00
sched_fair.c sched: fix weight calculations 2008-05-08 17:00:42 +02:00
sched_features.h sched: /debug/sched_features 2008-04-19 19:45:00 +02:00
sched_idletask.c sched: make rt_sched_class, idle_sched_class static 2008-05-05 23:56:17 +02:00
sched_rt.c sched: fix RT task-wakeup logic 2008-05-05 23:56:18 +02:00
sched_stats.h cpumask: use new cpus_scnprintf function 2008-04-19 19:44:59 +02:00
sched.c ftrace: make the task state char-string visible to all 2008-05-23 20:31:05 +02:00
seccomp.c
semaphore.c Revert "semaphore: fix" 2008-05-10 20:43:22 -07:00
signal.c signals: add set_restore_sigmask 2008-04-30 08:29:37 -07:00
softirq.c Fix cpu hotplug problem in softirq code 2008-05-01 08:03:58 -07:00
softlockup.c softlockup: fix task state setting 2008-02-29 18:46:53 +01:00
spinlock.c spinlock: lockbreak cleanup 2008-01-30 13:31:20 +01:00
srcu.c make srcu_readers_active() static 2008-02-06 10:41:02 -08:00
stacktrace.c
stop_machine.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/juhl/trivial 2008-04-21 16:36:46 -07:00
sys_ni.c timerfd: new timerfd API 2008-02-05 09:44:07 -08:00
sys.c pids: sys_getpgid: fix unsafe *pid usage, s/tasklist/rcu/ 2008-04-30 08:29:49 -07:00
sysctl_check.c constify tables in kernel/sysctl_check.c 2008-02-08 09:22:31 -08:00
sysctl.c [PATCH] avoid multiplication overflows and signedness issues for max_fds 2008-05-16 17:22:52 -04:00
taskstats.c Use find_task_by_vpid in taskstats 2008-04-30 08:29:48 -07:00
test_kprobes.c kprobes: kretprobe user entry-handler 2008-02-06 10:41:11 -08:00
time.c Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timeconst.pl Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timer.c debugobjects: add timer specific object debugging code 2008-04-30 08:29:53 -07:00
tsacct.c
uid16.c asmlinkage_protect replaces prevent_tail_call 2008-04-10 17:28:26 -07:00
user_namespace.c eCryptfs: make key module subsystem respect namespaces 2008-04-29 08:06:07 -07:00
user.c alloc_uid: cleanup 2008-04-30 08:29:53 -07:00
utsname_sysctl.c
utsname.c kernel: explicitly include required header files under kernel/ 2008-04-29 08:06:04 -07:00
wait.c kernel: remove fastcall in kernel/* 2008-02-08 09:22:31 -08:00
workqueue.c workqueue: remove redundant function invocation 2008-05-01 08:04:02 -07:00