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| author | Zhaolei <zhaolei@cn.fujitsu.com> | 2009-05-25 18:11:59 +0800 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2009-05-26 03:03:21 +0200 |
| commit | b11c53e12f94a46b50bccc7a1a953d7ca1d54a31 (patch) | |
| tree | a0d658e31ffd7f05834c6026874cd4120a35dd29 /kernel/trace/Kconfig | |
| parent | 29fcefba8a2f0fea11e2b721fe174a1832801284 (diff) | |
| download | lwn-b11c53e12f94a46b50bccc7a1a953d7ca1d54a31.tar.gz lwn-b11c53e12f94a46b50bccc7a1a953d7ca1d54a31.zip | |
ftrace: Add task_comm support for trace_event
If we enable a trace event alone without any tracer running (such as
function tracer, sched switch tracer, etc...) it can't output enough
task command information.
We need to use the tracing_{start/stop}_cmdline_record() helpers
which are designed to keep track of cmdlines for any tasks that
were scheduled during the tracing.
Before this patch:
# echo 1 > debugfs/tracing/events/sched/sched_switch/enable
# cat debugfs/tracing/trace
# tracer: nop
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
<...>-2289 [000] 526276.724790: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
<...>-2287 [000] 526276.725231: sched_switch: task sshd:2287 [120] ==> bash:2289 [120]
<...>-2289 [000] 526276.725452: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
<...>-2287 [000] 526276.727181: sched_switch: task sshd:2287 [120] ==> swapper:0 [140]
<idle>-0 [000] 526277.032734: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
<...>-5 [000] 526277.032782: sched_switch: task events/0:5 [115] ==> swapper:0 [140]
...
After this patch:
# tracer: nop
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
bash-2269 [000] 527347.989229: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
sshd-2267 [000] 527347.990960: sched_switch: task sshd:2267 [120] ==> bash:2269 [120]
bash-2269 [000] 527347.991143: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
sshd-2267 [000] 527347.992959: sched_switch: task sshd:2267 [120] ==> swapper:0 [140]
<idle>-0 [000] 527348.531989: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
events/0-5 [000] 527348.532115: sched_switch: task events/0:5 [115] ==> swapper:0 [140]
...
Changelog:
v1->v2: Update Kconfig to select CONTEXT_SWITCH_TRACER in
ENABLE_EVENT_TRACING
v2->v3: v2 can solve problem that was caused by config EVENT_TRACING
alone, but when CONFIG_FTRACE is off and CONFIG_TRACING is
selected by other config, compile fail happened again.
This version solves it.
[ Impact: fix incomplete output of event tracing ]
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index f61be3015783..a508b9d2adb8 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -49,6 +49,11 @@ config FTRACE_NMI_ENTER default y config EVENT_TRACING + select CONTEXT_SWITCH_TRACER + bool + +config CONTEXT_SWITCH_TRACER + select MARKERS bool config TRACING @@ -176,10 +181,10 @@ config SCHED_TRACER This tracer tracks the latency of the highest priority task to be scheduled in, starting from the point it has woken up. -config CONTEXT_SWITCH_TRACER +config ENABLE_CONTEXT_SWITCH_TRACER bool "Trace process context switches" select TRACING - select MARKERS + select CONTEXT_SWITCH_TRACER help This tracer gets called from the context switch and records all switching of tasks. |