[PATCH v2] rt-tests: pip_stress: Add option --usleep

[Shizhao Chen <shichen@redhat.com>]

Different hardwares have different threasholds for usleep_val to
reliably trigger an prio inversion, add option --usleep to allow
specifying it at runtime, to facilitate testing of prio inheritance
on different platforms.

Signed-off-by: Shizhao Chen <shichen@redhat.com>
---
 src/pi_tests/pip_stress.8 |  6 +++++-
 src/pi_tests/pip_stress.c | 10 ++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/pi_tests/pip_stress.8 b/src/pi_tests/pip_stress.8
index 0d06dd2..0f65ad1 100644
--- a/src/pi_tests/pip_stress.8
+++ b/src/pi_tests/pip_stress.8
@@ -5,7 +5,8 @@
 .B pip_stress \- Priority Inheritance with processes
 .SH SYNOPSIS
 .B pip_stress
-
+.RB [ \-u|\-\-usleep
+.IR TIME ]
 .SH DESCRIPTION
 This program demonstrates the technique of using priority inheritance (PI)
 mutexes with processes instead of threads.
@@ -41,6 +42,9 @@ merely increase the time that the low priority process sleeps while
 holding the lock. (usleep);
 Also note that you have to run as a user with permission to change
 scheduling priorities.
+.SH OPTIONS
+.IP "\-u TIME,\-\-usleep=TIME"
+Specify the sleep time in usec of the low priority process. Defaults to 500.
 .BR
 .SH AUTHOR
 pip_stress was written by John Kacur <jkacur at redhat.com>
diff --git a/src/pi_tests/pip_stress.c b/src/pi_tests/pip_stress.c
index fb0391b..9bd225f 100644
--- a/src/pi_tests/pip_stress.c
+++ b/src/pi_tests/pip_stress.c
@@ -72,7 +72,9 @@ static void usage(int error)
 	printf("pip_stress V %1.2f\n", VERSION);
 	printf("Usage:\n"
 	       "pip_stress <options>\n"\
-	       "-h	--help                  Show this help menu.\n"
+	       "-h       --help          Show this help menu.\n"\
+	       "-u TIME  --usleep=TIME   Specify the sleep time in usec of the low priority process.\n"\
+	       "                         Defaults to 500.\n"
 	       );
 	exit(error);
 }
@@ -88,16 +90,20 @@ int main(int argc, char *argv[])
 	for (;;) {
 		struct option long_options[] = {
 			{ "help",	no_argument,		NULL,	'h' },
+			{ "usleep",	required_argument,	NULL,	'u' },
 			{ NULL,		0,			NULL,	0 },
 		};
 
-		int c = getopt_long(argc, argv, "s:h", long_options, NULL);
+		int c = getopt_long(argc, argv, "hu:", long_options, NULL);
 		if (c == -1)
 			break;
 		switch (c) {
 		case 'h':
 			usage(0);
 			break;
+		case 'u':
+			usleep_val = strtoul(optarg, NULL, 10);
+			break;
 		default:
 			usage(1);
 			break;
-- 
2.47.1