perf script: Add more documentation about the -f/--fields parameters
Using the commit log for 2c9e45f.
Cc: David Ahern <daahern@cisco.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index 66f040b..86c87e2 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -113,13 +113,61 @@
Do various checks like samples ordering and lost events.
-f::
---fields
+--fields::
Comma separated list of fields to print. Options are:
comm, tid, pid, time, cpu, event, trace, sym. Field
- list must be prepended with the type, trace, sw or hw,
+ list can be prepended with the type, trace, sw or hw,
to indicate to which event type the field list applies.
e.g., -f sw:comm,tid,time,sym and -f trace:time,cpu,trace
+ perf script -f <fields>
+
+ is equivalent to:
+
+ perf script -f trace:<fields> -f sw:<fields> -f hw:<fields>
+
+ i.e., the specified fields apply to all event types if the type string
+ is not given.
+
+ The arguments are processed in the order received. A later usage can
+ reset a prior request. e.g.:
+
+ -f trace: -f comm,tid,time,sym
+
+ The first -f suppresses trace events (field list is ""), but then the
+ second invocation sets the fields to comm,tid,time,sym. In this case a
+ warning is given to the user:
+
+ "Overriding previous field request for all events."
+
+ Alternativey, consider the order:
+
+ -f comm,tid,time,sym -f trace:
+
+ The first -f sets the fields for all events and the second -f
+ suppresses trace events. The user is given a warning message about
+ the override, and the result of the above is that only S/W and H/W
+ events are displayed with the given fields.
+
+ For the 'wildcard' option if a user selected field is invalid for an
+ event type, a message is displayed to the user that the option is
+ ignored for that type. For example:
+
+ $ perf script -f comm,tid,trace
+ 'trace' not valid for hardware events. Ignoring.
+ 'trace' not valid for software events. Ignoring.
+
+ Alternatively, if the type is given an invalid field is specified it
+ is an error. For example:
+
+ perf script -v -f sw:comm,tid,trace
+ 'trace' not valid for software events.
+
+ At this point usage is displayed, and perf-script exits.
+
+ Finally, a user may not set fields to none for all event types.
+ i.e., -f "" is not allowed.
+
-k::
--vmlinux=<file>::
vmlinux pathname
