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| author | Zhaolei <zhaolei@cn.fujitsu.com> | 2009-05-25 12:11:59 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2009-05-26 03:03:21 +0200 |
| commit | b11c53e12f94a46b50bccc7a1a953d7ca1d54a31 (patch) | |
| tree | a0d658e31ffd7f05834c6026874cd4120a35dd29 | |
| parent | kmemtrace: fix kernel parameter documentation (diff) | |
| download | linux-b11c53e12f94a46b50bccc7a1a953d7ca1d54a31.tar.xz linux-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>
| -rw-r--r-- | kernel/trace/Kconfig | 9 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 6 |
2 files changed, 13 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. diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 9e91c4ad7c8b..9b246eb01d5f 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -85,6 +85,7 @@ static void ftrace_clear_events(void) if (call->enabled) { call->enabled = 0; + tracing_stop_cmdline_record(); call->unregfunc(); } } @@ -99,12 +100,14 @@ static void ftrace_event_enable_disable(struct ftrace_event_call *call, case 0: if (call->enabled) { call->enabled = 0; + tracing_stop_cmdline_record(); call->unregfunc(); } break; case 1: if (!call->enabled) { call->enabled = 1; + tracing_start_cmdline_record(); call->regfunc(); } break; @@ -1058,6 +1061,7 @@ static void trace_module_remove_events(struct module *mod) found = true; if (call->enabled) { call->enabled = 0; + tracing_stop_cmdline_record(); call->unregfunc(); } if (call->event) @@ -1262,11 +1266,13 @@ static __init void event_trace_self_tests(void) } call->enabled = 1; + tracing_start_cmdline_record(); call->regfunc(); event_test_stuff(); call->unregfunc(); + tracing_stop_cmdline_record(); call->enabled = 0; pr_cont("OK\n"); |