perf ftrace: Reuse target::initial_delay

Replace perf_ftrace::initial_delay with target::initial_delay.
Specifying a negative initial_delay is meaningless for ftrace in
practice but allowed here.
Signed-off-by: Changbin Du <changbin.du@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hui Wang <hw.huiwang@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230302031146.2801588-4-changbin.du@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-ftrace.c

@@ -623,7 +623,7 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace)
 	/* display column headers */
 	read_tracing_file_to_stdout("trace");
 
-	if (!ftrace->initial_delay) {
+	if (!ftrace->target.initial_delay) {
 		if (write_tracing_file("tracing_on", "1") < 0) {
 			pr_err("can't enable tracing\n");
 			goto out_close_fd;
@@ -632,8 +632,8 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace)
 
 	evlist__start_workload(ftrace->evlist);
 
-	if (ftrace->initial_delay) {
-		usleep(ftrace->initial_delay * 1000);
+	if (ftrace->target.initial_delay > 0) {
+		usleep(ftrace->target.initial_delay * 1000);
 		if (write_tracing_file("tracing_on", "1") < 0) {
 			pr_err("can't enable tracing\n");
 			goto out_close_fd;
@@ -1164,8 +1164,8 @@ int cmd_ftrace(int argc, const char **argv)
 		     "Size of per cpu buffer, needs to use a B, K, M or G suffix.", parse_buffer_size),
 	OPT_BOOLEAN(0, "inherit", &ftrace.inherit,
 		    "Trace children processes"),
-	OPT_UINTEGER('D', "delay", &ftrace.initial_delay,
-		     "Number of milliseconds to wait before starting tracing after program start"),
+	OPT_INTEGER('D', "delay", &ftrace.target.initial_delay,
+		    "Number of milliseconds to wait before starting tracing after program start"),
 	OPT_PARENT(common_options),
 	};
 	const struct option latency_options[] = {

tools/perf/util/ftrace.h

@@ -25,7 +25,6 @@ struct perf_ftrace {
 	int			graph_noirqs;
 	int			graph_verbose;
 	int			graph_thresh;
-	unsigned int		initial_delay;
 };
 
 struct filter_entry {