Steven Rostedt
352ad25aa4
ftrace: tracer for scheduler wakeup latency
...
This patch adds the tracer that tracks the wakeup latency of the
highest priority waking task.
"wakeup" is added to /debugfs/tracing/available_tracers
Also added to /debugfs/tracing
tracing_max_latency
holds the current max latency for the wakeup
wakeup_thresh
if set to other than zero, a log will be recorded
for every wakeup that takes longer than the number
entered in here (usecs for all counters)
(deletes previous trace)
Examples:
(with ftrace_enabled = 0)
============
preemption latency trace v1.1.5 on 2.6.24-rc8
Signed-off-by: Ingo Molnar <mingo@elte.hu>
--------------------------------------------------------------------
latency: 26 us, #2/2, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
-----------------
| task: migration/0-3 (uid:0 nice:-5 policy:1 rt_prio:99)
-----------------
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| /
||||| delay
cmd pid ||||| time | caller
\ / ||||| \ | /
quilt-8551 0d..3 0us+: wake_up_process+0x15/0x17 <ffffffff80233e80> (sched_exec+0xc9/0x100 <ffffffff80235343>)
quilt-8551 0d..4 26us : sched_switch_callback+0x73/0x81 <ffffffff80338d2f> (schedule+0x483/0x6d5 <ffffffff8048b3ee>)
vim:ft=help
============
(with ftrace_enabled = 1)
============
preemption latency trace v1.1.5 on 2.6.24-rc8
--------------------------------------------------------------------
latency: 36 us, #45/45, CPU#0 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2)
-----------------
| task: migration/1-5 (uid:0 nice:-5 policy:1 rt_prio:99)
-----------------
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| /
||||| delay
cmd pid ||||| time | caller
\ / ||||| \ | /
bash-10653 1d..3 0us : wake_up_process+0x15/0x17 <ffffffff80233e80> (sched_exec+0xc9/0x100 <ffffffff80235343>)
bash-10653 1d..3 1us : try_to_wake_up+0x271/0x2e7 <ffffffff80233dcf> (sub_preempt_count+0xc/0x7a <ffffffff8023309e>)
bash-10653 1d..2 2us : try_to_wake_up+0x296/0x2e7 <ffffffff80233df4> (update_rq_clock+0x9/0x20 <ffffffff802303f3>)
bash-10653 1d..2 2us : update_rq_clock+0x1e/0x20 <ffffffff80230408> (__update_rq_clock+0xc/0x90 <ffffffff80230366>)
bash-10653 1d..2 3us : __update_rq_clock+0x1b/0x90 <ffffffff80230375> (sched_clock+0x9/0x29 <ffffffff80214529>)
bash-10653 1d..2 4us : try_to_wake_up+0x2a6/0x2e7 <ffffffff80233e04> (activate_task+0xc/0x3f <ffffffff8022ffca>)
bash-10653 1d..2 4us : activate_task+0x2d/0x3f <ffffffff8022ffeb> (enqueue_task+0xe/0x66 <ffffffff8022ff66>)
bash-10653 1d..2 5us : enqueue_task+0x5b/0x66 <ffffffff8022ffb3> (enqueue_task_rt+0x9/0x3c <ffffffff80233351>)
bash-10653 1d..2 6us : try_to_wake_up+0x2ba/0x2e7 <ffffffff80233e18> (check_preempt_wakeup+0x12/0x99 <ffffffff80234f84>)
[...]
bash-10653 1d..5 33us : tracing_record_cmdline+0xcf/0xd4 <ffffffff80338aad> (_spin_unlock+0x9/0x33 <ffffffff8048d3ec>)
bash-10653 1d..5 34us : _spin_unlock+0x19/0x33 <ffffffff8048d3fc> (sub_preempt_count+0xc/0x7a <ffffffff8023309e>)
bash-10653 1d..4 35us : wakeup_sched_switch+0x65/0x2ff <ffffffff80339f66> (_spin_lock_irqsave+0xc/0xa9 <ffffffff8048d08b>)
bash-10653 1d..4 35us : _spin_lock_irqsave+0x19/0xa9 <ffffffff8048d098> (add_preempt_count+0xe/0x77 <ffffffff8023311a>)
bash-10653 1d..4 36us : sched_switch_callback+0x73/0x81 <ffffffff80338d2f> (schedule+0x483/0x6d5 <ffffffff8048b3ee>)
vim:ft=help
============
The [...] was added here to not waste your email box space.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:32:36 +02:00
Steven Rostedt
35e8e302e5
ftrace: add tracing of context switches
...
This patch adds context switch tracing, of the format of:
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| /
||||| delay
cmd pid ||||| time | pid:prio:state
\ / ||||| \ | /
swapper-0 1d..3 137us+: 0:140:R --> 2912:120
sshd-2912 1d..3 216us+: 2912:120:S --> 0:140
swapper-0 1d..3 261us+: 0:140:R --> 2912:120
bash-2920 0d..3 267us+: 2920:120:S --> 0:140
sshd-2912 1d..3 330us!: 2912:120:S --> 0:140
swapper-0 1d..3 2389us+: 0:140:R --> 2847:120
yum-upda-2847 1d..3 2411us!: 2847:120:S --> 0:140
swapper-0 0d..3 11089us+: 0:140:R --> 3139:120
gdm-bina-3139 0d..3 11113us!: 3139:120:S --> 0:140
swapper-0 1d..3 102328us+: 0:140:R --> 2847:120
yum-upda-2847 1d..3 102348us!: 2847:120:S --> 0:140
"sched_switch" is added to /debugfs/tracing/available_tracers
[ Eugene Teo <eugeneteo@kernel.sg: remove unused tracing_sched_switch_enabled ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:32:27 +02:00
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
Steven Rostedt
bc0c38d139
ftrace: latency tracer infrastructure
...
This patch adds the latency tracer infrastructure. This patch
does not add anything that will select and turn it on, but will
be used by later patches.
If it were to be compiled, it would add the following files
to the debugfs:
The root tracing directory:
/debugfs/tracing/
This patch also adds the following files:
available_tracers
list of available tracers. Currently no tracers are
available. Looking into this file only shows
"none" which is used to unregister all tracers.
current_tracer
The trace that is currently active. Empty on start up.
To switch to a tracer simply echo one of the tracers that
are listed in available_tracers:
example: (used with later patches)
echo function > /debugfs/tracing/current_tracer
To disable the tracer:
echo disable > /debugfs/tracing/current_tracer
tracing_enabled
echoing "1" into this file starts the ftrace function tracing
(if sysctl kernel.ftrace_enabled=1)
echoing "0" turns it off.
latency_trace
This file is readonly and holds the result of the trace.
trace
This file outputs a easier to read version of the trace.
iter_ctrl
Controls the way the output of traces look.
So far there's two controls:
echoing in "symonly" will only show the kallsyms variables
without the addresses (if kallsyms was configured)
echoing in "verbose" will change the output to show
a lot more data, but not very easy to understand by
humans.
echoing in "nosymonly" turns off symonly.
echoing in "noverbose" turns off verbose.
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 20:32:06 +02:00
Arnaldo Carvalho de Melo
16444a8a40
ftrace: add basic support for gcc profiler instrumentation
...
If CONFIG_FTRACE is selected and /proc/sys/kernel/ftrace_enabled is
set to a non-zero value the ftrace routine will be called everytime
we enter a kernel function that is not marked with the "notrace"
attribute.
The ftrace routine will then call a registered function if a function
happens to be registered.
[ This code has been highly hacked by Steven Rostedt and Ingo Molnar,
so don't blame Arnaldo for all of this ;-) ]
Update:
It is now possible to register more than one ftrace function.
If only one ftrace function is registered, that will be the
function that ftrace calls directly. If more than one function
is registered, then ftrace will call a function that will loop
through the functions to call.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:31:58 +02:00
Steven Rostedt
Arnaldo Carvalho de Melo