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Diffstat (limited to 'Documentation/trace/ftrace.rst')
| -rw-r--r-- | Documentation/trace/ftrace.rst | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index 67d9c38e95eb..a20d34955333 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -224,6 +224,8 @@ of ftrace. Here is a list of some of the key files: has a side effect of enabling or disabling specific functions to be traced. Echoing names of functions into this file will limit the trace to only those functions. + This influences the tracers "function" and "function_graph" + and thus also function profiling (see "function_profile_enabled"). The functions listed in "available_filter_functions" are what can be written into this file. @@ -265,6 +267,8 @@ of ftrace. Here is a list of some of the key files: Functions listed in this file will cause the function graph tracer to only trace these functions and the functions that they call. (See the section "dynamic ftrace" for more details). + Note, set_ftrace_filter and set_ftrace_notrace still affects + what functions are being traced. set_graph_notrace: @@ -277,7 +281,8 @@ of ftrace. Here is a list of some of the key files: This lists the functions that ftrace has processed and can trace. These are the function names that you can pass to - "set_ftrace_filter" or "set_ftrace_notrace". + "set_ftrace_filter", "set_ftrace_notrace", + "set_graph_function", or "set_graph_notrace". (See the section "dynamic ftrace" below for more details.) dyn_ftrace_total_info: @@ -507,6 +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 |