perf record: Extend -D,--delay option with -1 value

Extend -D,--delay option with -1 to start collection with events
disabled to be enabled later by 'enable' command provided via control
file descriptor.

Signed-off-by: Alexey Budankov <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Acked-by: Namhyung Kim <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-record.txt

···
 
 -D::
 --delay=::
-After starting the program, wait msecs before measuring. This is useful to
-filter out the startup phase of the program, which is often very different.
+After starting the program, wait msecs before measuring (-1: start with events
+disabled). This is useful to filter out the startup phase of the program, which
+is often very different.
 
 -I::
 --intr-regs::

tools/perf/builtin-record.c

···
 	}
 
 	if (opts->initial_delay) {
-		usleep(opts->initial_delay * USEC_PER_MSEC);
-		evlist__enable(rec->evlist);
+		pr_info(EVLIST_DISABLED_MSG);
+		if (opts->initial_delay > 0) {
+			usleep(opts->initial_delay * USEC_PER_MSEC);
+			evlist__enable(rec->evlist);
+			pr_info(EVLIST_ENABLED_MSG);
+		}
 	}
 
 	trigger_ready(&auxtrace_snapshot_trigger);
···
 	OPT_CALLBACK('G', "cgroup", &record.evlist, "name",
 		     "monitor event in cgroup name only",
 		     parse_cgroups),
-	OPT_UINTEGER('D', "delay", &record.opts.initial_delay,
-		  "ms to wait before starting measurement after program start"),
+	OPT_INTEGER('D', "delay", &record.opts.initial_delay,
+		  "ms to wait before starting measurement after program start (-1: start with events disabled)"),
 	OPT_BOOLEAN(0, "kcore", &record.opts.kcore, "copy /proc/kcore"),
 	OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
 		   "user to profile"),

tools/perf/builtin-trace.c

···
 			"per thread proc mmap processing timeout in ms"),
 	OPT_CALLBACK('G', "cgroup", &trace, "name", "monitor event in cgroup name only",
 		     trace__parse_cgroups),
-	OPT_UINTEGER('D', "delay", &trace.opts.initial_delay,
+	OPT_INTEGER('D', "delay", &trace.opts.initial_delay,
 		     "ms to wait before starting measurement after program "
 		     "start"),
 	OPTS_EVSWITCH(&trace.evswitch),

tools/perf/util/record.h

···
 	const char    *auxtrace_snapshot_opts;
 	const char    *auxtrace_sample_opts;
 	bool	      sample_transaction;
-	unsigned      initial_delay;
+	int	      initial_delay;
 	bool	      use_clockid;
 	clockid_t     clockid;
 	u64	      clockid_res_ns;