[PATCH] rt-tests: hachbench: Update the usage and man page for -F|--fifo option

[John Kacur <jkacur@redhat.com>]

From: Yunfeng Ye <yeyunfeng@huawei.com>

The commit 6c0c79b5152a ("hackbench mods to work better under stress")
add -F|--fifo option, but not update the usage and man page, so this
patch fix it.

Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>

Signed-off-by: John Kacur <jkacur@redhat.com>
- Fixed-up rejected patch hunk in man page
- Changed the wording in the man page
---
 src/hackbench/hackbench.8 | 6 +++++-
 src/hackbench/hackbench.c | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/hackbench/hackbench.8 b/src/hackbench/hackbench.8
index d86c52f27a2e..aaf572359704 100644
--- a/src/hackbench/hackbench.8
+++ b/src/hackbench/hackbench.8
@@ -7,7 +7,7 @@ hackbench \- scheduler benchmark/stress test
 .RI "[\-l|\-\-loops " <num\-loops> "] "
 .RI "[\-g|\-\-groups "<num\-groups> "] "
 .RI "[\-f|\-\-fds <num\-fds>] "
-.RI "[\-T|\-\-threads] [\-P|\-\-process] [\-\-help]"
+.RI "[\-T|\-\-threads] [\-P|\-\-process] [\-F|\-\-fifo] [\-\-help]"
 
 .SH "DESCRIPTION"
 Hackbench is both a benchmark and a stress test for the Linux kernel
@@ -45,6 +45,10 @@ Each sender/receiver child will be a POSIX thread of the parent.
 .TP 
 .B \-P, \-\-process
 Hackbench will use fork() on all children (default behaviour)
+.TP
+.B \-F,\-\-fifo
+Change the main thread to SCHED_FIFO after creating workers.
+This allows the management thread to run after many workers are created.
 .TP 
 .B \-\-help
 .br 
diff --git a/src/hackbench/hackbench.c b/src/hackbench/hackbench.c
index 5a883d341f2e..2cddff654df6 100644
--- a/src/hackbench/hackbench.c
+++ b/src/hackbench/hackbench.c
@@ -92,7 +92,7 @@ static void print_usage_exit()
 {
 	printf("Usage: hackbench [-p|--pipe] [-s|--datasize <bytes>] [-l|--loops <num loops>]\n"
 	       "\t\t [-g|--groups <num groups] [-f|--fds <num fds>]\n"
-	       "\t\t [-T|--threads] [-P|--process] [--help]\n");
+	       "\t\t [-T|--threads] [-P|--process] [-F|--fifo] [--help]\n");
 	exit(1);
 }
 
-- 
2.21.3