parse-events: Add filter on task comm

Add a 'COMM' special field to allow the filter in trace-cmd report
to filter on the task's comm.

Most records do not have data about what the comm is of the
task that recorded the record. But comms are stored in various
ways that parse-events can handle.

By adding a special field 'COMM' (all caps) the user can now
filter out tasks based on their name. This is useful when filtering
out (or in) a bunch of threads.

  -F 'COMM != "trace-cmd"'

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/trace-cmd-report.1.txt b/Documentation/trace-cmd-report.1.txt
index fbab3f4..86169f2 100644
--- a/Documentation/trace-cmd-report.1.txt
+++ b/Documentation/trace-cmd-report.1.txt
@@ -98,6 +98,14 @@ OPTIONS
 
     Although the output displays 'R', having 'prev_stat=="R"' will not work.
 
+    Note: You can also specify 'COMM' as an EVENT_FIELD. This will use the
+    task name (or comm) of the record to compare. For example, to filter out
+    all of the "trace-cmd" tasks:
+
+------------------------------------------
+    -F '.*:COMM != "trace-cmd"'
+------------------------------------------
+
 *-v*::
     This causes the following filters of *-F* to filter out the matching
     events.