A few people have asked for this in the past, and I finally got around to implementing it. What this does is to allow writes into trace_marker to initiate a trigger. The trace_marker event is described in: tracefs/events/ftrace/print Thus the trigger file is added there: tracefs/events/ftrace/print/trigger As there's already a "hist" file there, everything appears to work just like any other trigger to an event. See the last patch for documentation on how to use the triggers to a trace_marker write. By the way, the patch: tracing: Prevent further users of zero size static arrays in trace events May prevent your kernel from building if you include Xen. You will need to add this patch to make it work. http://lkml.kernel.org/r/20180509144605.5a220327@xxxxxxxxxxxxxxxxxx -- Steve Steven Rostedt (VMware) (10): tracing: Do not reference event data in post call triggers tracing: Add __find_event_file() to find event files without restrictions tracing: Have event_trace_init() called by trace_init_tracefs() tracing: Add brackets in ftrace event dynamic arrays tracing: Do not show filter file for ftrace internal events tracing: Add trigger file for trace_markers tracefs/ftrace/print tracing: Have zero size length in filter logic be full string tracing: Prevent further users of zero size static arrays in trace events tracing: Allow histogram triggers to access ftrace internal events tracing: Document trace_marker triggers ---- Documentation/trace/events.rst | 6 +- Documentation/trace/ftrace.rst | 5 + Documentation/trace/histogram.txt | 546 +++++++++++++++++++++++++++++++++++- include/linux/trace_events.h | 3 +- include/trace/trace_events.h | 1 + kernel/trace/trace.c | 19 ++ kernel/trace/trace.h | 9 +- kernel/trace/trace_entries.h | 6 +- kernel/trace/trace_events.c | 36 ++- kernel/trace/trace_events_filter.c | 23 +- kernel/trace/trace_events_hist.c | 2 +- kernel/trace/trace_events_trigger.c | 6 +- kernel/trace/trace_export.c | 9 +- 13 files changed, 634 insertions(+), 37 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
