Switch to using our internal Tausworthe based random generator for offsets
It's both faster and more exhaustive than what is available on
glibc on my test systems. So no downsides, and the upside of having
the same offset generator across all platforms.
This will change the random series, so could alter performance for
your workload since the pattern will be different in sequence. There's
an option to revert to the OS generator, you can add use_us_rand=1
on your job files to retain the old generator offsets.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/fio.h b/fio.h
index 08f1733..e5607bc 100644
--- a/fio.h
+++ b/fio.h
@@ -34,6 +34,7 @@
#include "profile.h"
#include "time.h"
#include "lib/getopt.h"
+#include "lib/rand.h"
#ifdef FIO_HAVE_GUASI
#include <guasi.h>
@@ -206,6 +207,7 @@
unsigned int do_disk_util;
unsigned int override_sync;
unsigned int rand_repeatable;
+ unsigned int use_os_rand;
unsigned int write_lat_log;
unsigned int write_bw_log;
unsigned int norandommap;
@@ -416,6 +418,7 @@
* State for random io, a bitmap of blocks done vs not done
*/
os_random_state_t random_state;
+ struct frand_state __random_state;
struct timeval start; /* start of this loop */
struct timeval epoch; /* time job was started */