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From: Brian Norris <computersforpeace@gmail.com>
To: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Jan Weitzel <j.weitzel@phytec.de>,
	Brian Norris <computersforpeace@gmail.com>,
	linux-mtd@lists.infradead.org
Subject: [PATCH v2] nandtest: seed random generator with time
Date: Fri,  2 Dec 2011 09:46:12 -0800	[thread overview]
Message-ID: <1322847972-26504-1-git-send-email-computersforpeace@gmail.com> (raw)
In-Reply-To: <1322730350.2332.28.camel@koala>

If a seed is not provided via --seed, we use the default rand() values,
which produces the same sequence of values every run. Since this is
undesirable, we should choose a random seed via the current time().

Note that this patch moves the srand() until after all the initial
options processing.

Cc: Jan Weitzel <j.weitzel@phytec.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
rebased on top of Jan's patch

 nandtest.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/nandtest.c b/nandtest.c
index b3aacaf..0187b87 100644
--- a/nandtest.c
+++ b/nandtest.c
@@ -140,6 +140,8 @@ int main(int argc, char **argv)
 	uint32_t offset = 0;
 	uint32_t length = -1;
 
+	seed = time(NULL);
+
 	for (;;) {
 		static const char *short_options="hkl:mo:p:s:";
 		static const struct option long_options[] = {
@@ -173,7 +175,6 @@ int main(int argc, char **argv)
 
 		case 's':
 			seed = atol(optarg);
-			srand(seed);
 			break;
 
 		case 'p':
@@ -244,6 +245,8 @@ int main(int argc, char **argv)
 	printf("Bad blocks     : %d\n", oldstats.badblocks);
 	printf("BBT blocks     : %d\n", oldstats.bbtblocks);
 
+	srand(seed);
+
 	for (pass = 0; pass < nr_passes; pass++) {
 		loff_t test_ofs;
 
-- 
1.7.5.4

  reply	other threads:[~2011-12-02 17:46 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-24 10:57 [PATCH] nandtest: use seed argument Jan Weitzel
2011-11-28 17:56 ` Brian Norris
2011-11-28 18:11   ` [PATCH] nandtest: seed random generator properly Brian Norris
2011-11-29  7:30     ` Antwort: " Jan Weitzel
2011-11-30 18:24       ` Brian Norris
2011-12-01  8:23         ` Jan Weitzel
2011-12-01  9:05         ` Artem Bityutskiy
2011-12-02 17:46           ` Brian Norris [this message]
2011-12-05  6:30             ` [PATCH v2] nandtest: seed random generator with time Artem Bityutskiy
2011-12-01  7:56 ` [PATCH] nandtest: use seed argument Artem Bityutskiy

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