tracing: Add support for named hist triggers
authorTom Zanussi <tom.zanussi@linux.intel.com>
Thu, 3 Mar 2016 18:54:59 +0000 (12:54 -0600)
committerSteven Rostedt <rostedt@goodmis.org>
Tue, 19 Apr 2016 22:56:01 +0000 (18:56 -0400)
commit5463bfda327b1f7310556ef3136533e27c774f13
tree2221e87e917ba0652329ef47c1f40c024b9e5697
parentdb1388b4ffa9e31e9ff0abacc3bdb121bec8c688
tracing: Add support for named hist triggers

Allow users to define 'named' hist triggers.  All triggers created
with the same 'name=xxx' option will update the same shared histogram
data.

This expands the hist trigger syntax from this:

    # echo hist:keys=xxx ... [ if filter] > event/trigger

to this:

    # echo hist:name=xxx:keys=xxx ... [ if filter] > event/trigger

Named histograms must use a 'compatible' set of keys and values, which
means each event added to a set of named triggers must have the same
names and types.

Reading the 'hist' file of any of the participating events will
produce the same output as any other participating event, which is to
be expected since they share the same data.

Link: http://lkml.kernel.org/r/1dbc84ee3322a75daaf5b3ef1d0cc0a2fb682fc7.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Documentation/trace/events.txt
kernel/trace/trace.c
kernel/trace/trace_events_hist.c