Follow-up on php#8914, usage comments addition.

Author: devnexen

ext/opcache/jit/zend_jit_perf_dump.c

@@ -279,6 +279,14 @@ static void zend_jit_perf_map_register(const char *name, void *start, size_t siz
 #include <os/log.h>
 #include <os/signpost.h>
 
+/*
+ * 1) To generate an Instrument tracing data:
+ * xcrun xctrace record --template <Template name> --launch -- php
+ * xcrun xctrace record --template Logging --launch -- php -dopcache.jit=1255 -dopcache.jit_debug=32 bench.php
+ * 2) An instrument trace folder is created:
+ * e.g. open Launch_php_2022-07-03_15.41.05_5F96D825.trace
+ */
+
 static os_log_t jitdump_fd;
 static os_signpost_id_t jitdump_sp = OS_SIGNPOST_ID_NULL;