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authorMasami Hiramatsu <mhiramat@redhat.com>2009-09-14 16:49:37 -0400
committerFrederic Weisbecker <fweisbec@gmail.com>2009-09-17 04:04:01 +0200
commit5a0d9050db4d1147722b42afef9011251b2651ee (patch)
tree1d3b3e080d4b3d1bf34d0a551ee3c06be0852331 /Documentation/trace/kprobetrace.txt
parent74ebb63e7cd25f6fb02a45fc2ea7735bce1217c9 (diff)
downloadlwn-5a0d9050db4d1147722b42afef9011251b2651ee.tar.gz
lwn-5a0d9050db4d1147722b42afef9011251b2651ee.zip
tracing/kprobes: Disable kprobe events by default after creation
Disable newly created kprobe events by default, not to disturb another user using ftrace. "Disturb" means when someone is using ftrace and another user tries to use perf-tools, (in near future) if he defines new kprobe event via perf-tools, then new events will mess up the frace buffer. Fix this to allow proper and transparent kprobes events concurrent usage between ftrace users and perf users. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jason Baron <jbaron@redhat.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <20090914204937.18779.59422.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'Documentation/trace/kprobetrace.txt')
-rw-r--r--Documentation/trace/kprobetrace.txt11
1 files changed, 9 insertions, 2 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 6521681e7838..9b8f7c6040a7 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -122,8 +122,15 @@ print fmt: "(%lx) dfd=%lx filename=%lx flags=%lx mode=%lx", REC->ip, REC->dfd, R
echo > /sys/kernel/debug/tracing/kprobe_events
- This clears all probe points. and you can see the traced information via
-/sys/kernel/debug/tracing/trace.
+ This clears all probe points.
+
+ Right after definition, each event is disabled by default. For tracing these
+events, you need to enable it.
+
+ echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable
+ echo 1 > /sys/kernel/debug/tracing/events/kprobes/myretprobe/enable
+
+ And you can see the traced information via /sys/kernel/debug/tracing/trace.
cat /sys/kernel/debug/tracing/trace
# tracer: nop