From 83e99914c9e2677d8a80f2a23eca0d215d5bfb0f Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 3 Mar 2016 12:54:46 -0600 Subject: tracing: Add hist trigger support for pausing and continuing a trace Allow users to append 'pause' or 'continue' to an existing trigger in order to have it paused or to have a paused trace continue. This expands the hist trigger syntax from this: # echo hist:keys=xxx:vals=yyy:sort=zzz.descending \ [ if filter] >> event/trigger to this: # echo hist:keys=xxx:vals=yyy:sort=zzz.descending:pause or cont \ [ if filter] >> event/trigger Link: http://lkml.kernel.org/r/b672a92c14702cb924cdf6fc27ea1809bed04907.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Tested-by: Masami Hiramatsu Reviewed-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d16fa8e1cdbf..7d5c63dd410a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3837,6 +3837,7 @@ static const char readme_msg[] = "\t [:values=]\n" "\t [:sort=]\n" "\t [:size=#entries]\n" + "\t [:pause][:continue]\n" "\t [if ]\n\n" "\t When a matching event is hit, an entry is added to a hash\n" "\t table using the key(s) and value(s) named, and the value of a\n" @@ -3851,7 +3852,11 @@ static const char readme_msg[] = "\t used to specify more or fewer than the default 2048 entries\n" "\t for the hashtable size.\n\n" "\t Reading the 'hist' file for the event will dump the hash\n" - "\t table in its entirety to stdout." + "\t table in its entirety to stdout.\n\n" + "\t The 'pause' parameter can be used to pause an existing hist\n" + "\t trigger or to start a hist trigger but not log any events\n" + "\t until told to do so. 'continue' can be used to start or\n" + "\t restart a paused hist trigger.\n\n" #endif ; -- cgit v1.2.3