From: Jens Axboe <axboe@kernel.dk>
Date: Fri, 7 Jul 2017 14:33:57 +0000 (-0600)
Subject: io_u: sequence random buflen generation individually
X-Git-Tag: fio-2.99~2
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=2f282cecc27c58ed3aa1204f5bda98433502d7ff;hp=f25f4ef6d123173d7669553ec712419f95c1a3ea

io_u: sequence random buflen generation individually

For trimwrite, we rely on write+trim generating identical
buffer lengths, if they have identical settings. If we use
bssplit, then we generate them using a random generator
according to the percentages set. This means we may not get
the same offsets in sequence.

Split the seeding into separate random generators, and ensure
that we seed the write and trim ones identically, if we are
doing trim writes.

Fixes: https://github.com/axboe/fio/issues/399
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/fio.h b/fio.h
index d5d6bfe4..39d775c0 100644
--- a/fio.h
+++ b/fio.h
@@ -91,6 +91,8 @@ enum {
 
 enum {
 	FIO_RAND_BS_OFF		= 0,
+	FIO_RAND_BS1_OFF,
+	FIO_RAND_BS2_OFF,
 	FIO_RAND_VER_OFF,
 	FIO_RAND_MIX_OFF,
 	FIO_RAND_FILE_OFF,
@@ -214,7 +216,7 @@ struct thread_data {
 
 	unsigned long rand_seeds[FIO_RAND_NR_OFFS];
 
-	struct frand_state bsrange_state;
+	struct frand_state bsrange_state[DDIR_RWDIR_CNT];
 	struct frand_state verify_state;
 	struct frand_state trim_state;
 	struct frand_state delay_state;
diff --git a/init.c b/init.c
index a4b5adb8..1f1ceebf 100644
--- a/init.c
+++ b/init.c
@@ -921,7 +921,16 @@ static void td_fill_rand_seeds_internal(struct thread_data *td, bool use64)
 {
 	int i;
 
-	init_rand_seed(&td->bsrange_state, td->rand_seeds[FIO_RAND_BS_OFF], use64);
+	if (td_trimwrite(td)) {
+		init_rand_seed(&td->bsrange_state[DDIR_READ], td->rand_seeds[FIO_RAND_BS_OFF], use64);
+		init_rand_seed(&td->bsrange_state[DDIR_WRITE], td->rand_seeds[FIO_RAND_BS1_OFF], use64);
+		init_rand_seed(&td->bsrange_state[DDIR_TRIM], td->rand_seeds[FIO_RAND_BS1_OFF], use64);
+	} else {
+		init_rand_seed(&td->bsrange_state[DDIR_READ], td->rand_seeds[FIO_RAND_BS_OFF], use64);
+		init_rand_seed(&td->bsrange_state[DDIR_WRITE], td->rand_seeds[FIO_RAND_BS1_OFF], use64);
+		init_rand_seed(&td->bsrange_state[DDIR_TRIM], td->rand_seeds[FIO_RAND_BS2_OFF], use64);
+	}
+
 	td_fill_verify_state_seed(td);
 	init_rand_seed(&td->rwmix_state, td->rand_seeds[FIO_RAND_MIX_OFF], false);
 
diff --git a/io_u.c b/io_u.c
index 8d42d654..ed8e84ab 100644
--- a/io_u.c
+++ b/io_u.c
@@ -552,9 +552,9 @@ static unsigned int __get_next_buflen(struct thread_data *td, struct io_u *io_u,
 	if (!io_u_fits(td, io_u, minbs))
 		return 0;
 
-	frand_max = rand_max(&td->bsrange_state);
+	frand_max = rand_max(&td->bsrange_state[ddir]);
 	do {
-		r = __rand(&td->bsrange_state);
+		r = __rand(&td->bsrange_state[ddir]);
 
 		if (!td->o.bssplit_nr[ddir]) {
 			buflen = 1 + (unsigned int) ((double) maxbs *