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authorSteven Rostedt <rostedt@goodmis.org>2008-07-10 20:58:09 -0400
committerIngo Molnar <mingo@elte.hu>2008-07-11 15:49:18 +0200
commit007c05d4d2ce42fabd58cb54ed98e0a1714d9d86 (patch)
tree94873072975275a1e03ccc1dad27a15c41ee3cc4 /kernel
parent98a05ed4bd7774f533ab185fe0bf2fdc58292d7c (diff)
ftrace: move sched_switch enable after markers
We have two markers now that are enabled on sched_switch. One that records the context switching and the other that records task wake ups. Currently we enable the tracing first and then set the markers. This causes some confusing traces: # tracer: sched_switch # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | trace-cmd-3973 [00] 115.834817: 3973:120:R + 3: 0:S trace-cmd-3973 [01] 115.834910: 3973:120:R + 6: 0:S trace-cmd-3973 [02] 115.834910: 3973:120:R + 9: 0:S trace-cmd-3973 [03] 115.834910: 3973:120:R + 12: 0:S trace-cmd-3973 [02] 115.834910: 3973:120:R + 9: 0:S <idle>-0 [02] 115.834910: 0:140:R ==> 3973:120:R Here we see that trace-cmd with PID 3973 wakes up task 9 but the next line shows the idle task doing a context switch to task 3973. Enabling the tracing to _after_ the markers are set creates a much saner output: # tracer: sched_switch # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <idle>-0 [02] 7922.634225: 0:140:R ==> 4790:120:R trace-cmd-4789 [03] 7922.634225: 0:140:R + 4790:120:R Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_sched_switch.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 93a66200915..cb817a209aa 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -227,14 +227,14 @@ void tracing_stop_cmdline_record(void)
static void start_sched_trace(struct trace_array *tr)
{
sched_switch_reset(tr);
- tracer_enabled = 1;
tracing_start_cmdline_record();
+ tracer_enabled = 1;
}
static void stop_sched_trace(struct trace_array *tr)
{
- tracing_stop_cmdline_record();
tracer_enabled = 0;
+ tracing_stop_cmdline_record();
}
static void sched_switch_trace_init(struct trace_array *tr)