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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-07 02:39:18 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-07 02:39:18 +0300
commit5eb6eed7e0fe880dc8de8da203cc888716bbf196 (patch)
tree05a7c83182b34a567c68b35c091cf31200d5ddec /Documentation/trace/ftrace.rst
parent8b5c6a3a49d9ebc7dc288870b9c56c4f946035d8 (diff)
parent591a033dc17ff6f684b6b6d1d7426e22d178194f (diff)
downloadlinux-5eb6eed7e0fe880dc8de8da203cc888716bbf196.tar.xz
Merge tag 'trace-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt: "One new feature was added to ftrace, which is the trace_marker now supports triggers. For example: # cd /sys/kernel/debug/tracing # echo 'snapshot' > events/ftrace/print/trigger # echo 'cause snapshot' > trace_marker The rest of the changes are various clean ups and also one stable fix that was added late in the cycle" * tag 'trace-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (21 commits) tracing: Use match_string() instead of open coding it in trace_set_options() branch-check: fix long->int truncation when profiling branches ring-buffer: Fix typo in comment ring-buffer: Fix a bunch of typos in comments tracing/selftest: Add test to test simple snapshot trigger for trace_marker tracing/selftest: Add test to test hist trigger between kernel event and trace_marker tracing/selftest: Add selftests to test trace_marker histogram triggers ftrace/selftest: Fix reset_trigger() to handle triggers with filters ftrace/selftest: Have the reset_trigger code be a bit more careful tracing: Document trace_marker triggers tracing: Allow histogram triggers to access ftrace internal events tracing: Prevent further users of zero size static arrays in trace events tracing: Have zero size length in filter logic be full string tracing: Add trigger file for trace_markers tracefs/ftrace/print tracing: Do not show filter file for ftrace internal events tracing: Add brackets in ftrace event dynamic arrays tracing: Have event_trace_init() called by trace_init_tracefs() tracing: Add __find_event_file() to find event files without restrictions tracing: Do not reference event data in post call triggers tracepoints: Fix the descriptions of tracepoint_probe_register{_prio} ...
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diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 6b80ac4bbaae..a20d34955333 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -512,6 +512,11 @@ of ftrace. Here is a list of some of the key files:
trace_fd = open("trace_marker", WR_ONLY);
+ Note: Writing into the trace_marker file can also initiate triggers
+ that are written into /sys/kernel/tracing/events/ftrace/print/trigger
+ See "Event triggers" in Documentation/trace/events.rst and an
+ example in Documentation/trace/histogram.rst (Section 3.)
+
trace_marker_raw:
This is similar to trace_marker above, but is meant for for binary data