perf report: Add -q/--quiet option

The -q/--quiet option is to suppress any message. Sometimes users just
want to see the numbers and it can be used for that case.

Before:

$ perf report | head -15
Failed to open /lib/modules/3.19.3-3-ARCH/kernel/fs/ext4/ext4.ko.gz, continuing without symbols
Failed to open /lib/modules/3.19.3-3-ARCH/kernel/fs/jbd2/jbd2.ko.gz, continuing without symbols
Failed to open /tmp/perf-14507.map, continuing without symbols
...
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 39K of event 'cycles'
# Event count (approx.): 30444796573
#
# Overhead Command Shared Object Symbol
# ........ ........... ................... .........................
#
9.28% swapper [kernel.vmlinux] [k] intel_idle
5.64% swapper [kernel.vmlinux] [k] native_write_msr_safe
1.93% swapper [kernel.vmlinux] [k] __switch_to
1.89% swapper [kernel.vmlinux] [k] menu_select
1.75% sched-pipe [kernel.vmlinux] [k] __switch_to

After:

$ perf report -q | head
9.28% swapper [kernel.vmlinux] [k] intel_idle
5.64% swapper [kernel.vmlinux] [k] native_write_msr_safe
1.93% swapper [kernel.vmlinux] [k] __switch_to
1.89% swapper [kernel.vmlinux] [k] menu_select
1.75% sched-pipe [kernel.vmlinux] [k] __switch_to
1.67% swapper [kernel.vmlinux] [k] cpu_startup_entry
1.48% sched-pipe [kernel.vmlinux] [k] enqueue_entity
1.46% swapper [kernel.vmlinux] [k] __schedule
1.36% swapper [kernel.vmlinux] [k] native_read_tsc
1.34% sched-pipe [kernel.vmlinux] [k] __schedule

Signed-off-by: Namhyung Kim <[e-mail]>
Suggested-and-Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
[ Removed builtin-report.c verbose > 0 hunk added to the previous patch ]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-report.txt

···
 --verbose::
         Be more verbose. (show symbol address, etc)
 
+-q::
+--quiet::
+	Do not show any message.  (Suppress -v)
+
 -n::
 --show-nr-samples::
 	Show the number of samples for each symbol

tools/perf/builtin-report.c

···
 	size_t size = sizeof(buf);
 	int socked_id = hists->socket_filter;
 
+	if (quiet)
+		return 0;
+
 	if (symbol_conf.filter_relative) {
 		nr_samples = hists->stats.nr_non_filtered_samples;
 		nr_events = hists->stats.total_non_filtered_period;
···
 {
 	struct perf_evsel *pos;
 
-	fprintf(stdout, "#\n# Total Lost Samples: %" PRIu64 "\n#\n", evlist->stats.total_lost_samples);
+	if (!quiet) {
+		fprintf(stdout, "#\n# Total Lost Samples: %" PRIu64 "\n#\n",
+			evlist->stats.total_lost_samples);
+	}
+
 	evlist__for_each_entry(evlist, pos) {
 		struct hists *hists = evsel__hists(pos);
 		const char *evname = perf_evsel__name(pos);
···
 			continue;
 
 		hists__fprintf_nr_sample_events(hists, rep, evname, stdout);
-		hists__fprintf(hists, true, 0, 0, rep->min_percent, stdout,
+		hists__fprintf(hists, !quiet, 0, 0, rep->min_percent, stdout,
 			       symbol_conf.use_callchain);
 		fprintf(stdout, "\n\n");
 	}
···
 		    "input file name"),
 	OPT_INCR('v', "verbose", &verbose,
 		    "be more verbose (show symbol address, etc)"),
+	OPT_BOOLEAN('q', "quiet", &quiet, "Do not show any message"),
 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
 		    "dump raw trace in ASCII"),
 	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
···
 		report.symbol_filter_str = argv[0];
 	}
 
+	if (quiet)
+		perf_quiet_option();
+
 	if (symbol_conf.vmlinux_name &&
 	    access(symbol_conf.vmlinux_name, R_OK)) {
 		pr_err("Invalid file: %s\n", symbol_conf.vmlinux_name);
···
 		goto error;
 	}
 
-	if (report.header || report.header_only) {
+	if ((report.header || report.header_only) && !quiet) {
 		perf_session__fprintf_info(session, stdout,
 					   report.show_full_info);
 		if (report.header_only) {
 			ret = 0;
 			goto error;
 		}
-	} else if (use_browser == 0) {
+	} else if (use_browser == 0 && !quiet) {
 		fputs("# To display the perf.data header info, please use --header/--header-only options.\n#\n",
 		      stdout);
 	}