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 d5d6bfe42fcde0d1dcb8711cc31e4e774a673fd4..39d775c0677dfadbda23c25b68b55014149b44ff 100644 (file)
--- a/fio.h
+++ b/fio.h
@@ -91,6 +91,8 @@ enum {
 
 enum {
        FIO_RAND_BS_OFF         = 0,
 
 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,
        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];
 
 
        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;
        struct frand_state verify_state;
        struct frand_state trim_state;
        struct frand_state delay_state;

diff --git a/init.c b/init.c
index a4b5adb8e2f30bf7e20100b34db12cd4b8a8a341..1f1ceebf33a7d432ad29825a106c5759d0d9bcc8 100644 (file)
--- 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;
 
 {
        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);
 
        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 8d42d6541f7dbb9592639619874295153101bd91..ed8e84aba41f2a5c48e7d2cc66c79efd849a5c75 100644 (file)
--- 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;
 
        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 {
        do {

-               r = __rand(&td->bsrange_state);
+               r = __rand(&td->bsrange_state[ddir]);

 
                if (!td->o.bssplit_nr[ddir]) {
                        buflen = 1 + (unsigned int) ((double) maxbs *
 
                if (!td->o.bssplit_nr[ddir]) {
                        buflen = 1 + (unsigned int) ((double) maxbs *