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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-02-02 20:29:21 -0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-02-03 14:03:52 +0100 |
| commit | c4a8e8be2d43cc22b371e8e9c05c253409759d94 (patch) | |
| tree | 274962a78a082a11550d07c6cc088817d6558db5 /kernel/trace/trace_output.h | |
| parent | dc573f9b20c8710105ac35c08ed0fe1da5160ecd (diff) | |
| download | lwn-c4a8e8be2d43cc22b371e8e9c05c253409759d94.tar.gz lwn-c4a8e8be2d43cc22b371e8e9c05c253409759d94.zip | |
trace: better manage the context info for events
Impact: make trace_event more convenient for tracers
All tracers (for the moment) that use the struct trace_event want to
have the context info printed before their own output: the pid/cmdline,
cpu, and timestamp.
But some other tracers that want to implement their trace_event
callbacks will not necessary need these information or they may want to
format them as they want.
This patch adds a new default-enabled trace option:
TRACE_ITER_CONTEXT_INFO When disabled through:
echo nocontext-info > /debugfs/tracing/trace_options
The pid, cpu and timestamps headers will not be printed.
IE with the sched_switch tracer with context-info (default):
bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle>
<idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0
<idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0
events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle>
Without context-info:
2935:120:S ==> [001] 0:140:R <idle>
0:140:R + [000] 11:115:S events/0
0:140:R ==> [000] 11:115:R events/0
11:115:S ==> [000] 0:140:R <idle>
A tracer can disable it at runtime by clearing the bit
TRACE_ITER_CONTEXT_INFO in trace_flags.
The print routines were renamed to trace_print_context and
trace_print_lat_context, so that they can be used by tracers if they
want to use them for one of the trace_event callbacks.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace_output.h')
| -rw-r--r-- | kernel/trace/trace_output.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index 1cbab5e3dc99..ec2ed90f10f0 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -33,6 +33,9 @@ int seq_print_userip_objs(const struct userstack_entry *entry, int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm, unsigned long ip, unsigned long sym_flags); +int trace_print_context(struct trace_iterator *iter); +int trace_print_lat_context(struct trace_iterator *iter); + struct trace_event *ftrace_find_event(int type); int register_ftrace_event(struct trace_event *event); int unregister_ftrace_event(struct trace_event *event); |