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authorZhaolei <zhaolei@cn.fujitsu.com>2009-05-25 18:11:59 +0800
committerFrederic Weisbecker <fweisbec@gmail.com>2009-05-26 03:03:21 +0200
commitb11c53e12f94a46b50bccc7a1a953d7ca1d54a31 (patch)
treea0d658e31ffd7f05834c6026874cd4120a35dd29 /kernel/trace
parent29fcefba8a2f0fea11e2b721fe174a1832801284 (diff)
downloadop-kernel-dev-b11c53e12f94a46b50bccc7a1a953d7ca1d54a31.zip
op-kernel-dev-b11c53e12f94a46b50bccc7a1a953d7ca1d54a31.tar.gz
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')
-rw-r--r--kernel/trace/Kconfig9
-rw-r--r--kernel/trace/trace_events.c6
2 files changed, 13 insertions, 2 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index f61be30..a508b9d 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 9e91c4a..9b246eb 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");
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