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authorFrederic Weisbecker <fweisbec@gmail.com>2009-02-02 20:29:21 -0200
committerIngo Molnar <mingo@elte.hu>2009-02-03 14:03:52 +0100
commitc4a8e8be2d43cc22b371e8e9c05c253409759d94 (patch)
tree274962a78a082a11550d07c6cc088817d6558db5 /kernel/trace/trace_output.h
parentdc573f9b20c8710105ac35c08ed0fe1da5160ecd (diff)
downloadlwn-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.h3
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);