perf script: Add comm filtering option

Allows collecting events system wide and then pulling out events for a
specific task name(s). e.g,

    perf script -c gnome-shell,gnome-terminal

Applies on top of:
    https://lkml.org/lkml/2011/11/13/74

v2->v3
- update Documentation

v1->v2
- use comm_list from symbol_conf

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1321894972-24246-1-git-send-email-dsahern@gmail.comSigned-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-script.txt

@@ -188,6 +188,11 @@ OPTIONS
 	CPUs are specified with -: 0-2. Default is to report samples on all
 	CPUs.
 
+-c::
+--comms=::
+	Only display events for these comms. CSV that understands
+	file://filename entries.
+
 -I::
 --show-info::
 	Display extended information about the perf.data file. This adds

tools/perf/builtin-script.c

@@ -441,6 +441,7 @@ static int process_sample_event(struct perf_tool *tool __used,
 				struct perf_evsel *evsel,
 				struct machine *machine)
 {
+	struct addr_location al;
 	struct thread *thread = machine__findnew_thread(machine, event->ip.pid);
 
 	if (thread == NULL) {
@@ -460,6 +461,15 @@ static int process_sample_event(struct perf_tool *tool __used,
 		return 0;
 	}
 
+	if (perf_event__preprocess_sample(event, machine, &al, sample, 0) < 0) {
+		pr_err("problem processing %d event, skipping it.\n",
+		       event->header.type);
+		return -1;
+	}
+
+	if (al.filtered)
+		return 0;
+
 	if (cpu_list && !test_bit(sample->cpu, cpu_bitmap))
 		return 0;
 
@@ -1086,6 +1096,8 @@ static const struct option options[] = {
 		     "comma separated output fields prepend with 'type:'. Valid types: hw,sw,trace,raw. Fields: comm,tid,pid,time,cpu,event,trace,ip,sym,dso,addr",
 		     parse_output_fields),
 	OPT_STRING('C', "cpu", &cpu_list, "cpu", "list of cpus to profile"),
+	OPT_STRING('c', "comms", &symbol_conf.comm_list_str, "comm[,comm...]",
+		   "only display events for these comms"),
 	OPT_BOOLEAN('I', "show-info", &show_full_info,
 		    "display extended information from perf.data file"),
 	OPT_END()