Improve bsrange buflen generations

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/io_u.c b/io_u.c
index 92b707647cc17bf40805f6b7055a675374bf8b0b..0d24b189fece6ee48d11e4f3bf493af271f2731e 100644 (file)
--- a/io_u.c
+++ b/io_u.c
@@ -77,7 +77,6 @@ static void mark_random_map(struct thread_data *td, struct io_u *io_u)
                else
                        mask = ((1U << this_blocks) - 1) << bit;
 
-               fio_assert(td, !(f->file_map[idx] & mask));
                f->file_map[idx] |= mask;
                nr_blocks -= this_blocks;
                blocks += this_blocks;
@@ -228,20 +227,30 @@ static int get_next_offset(struct thread_data *td, struct io_u *io_u)
        return 0;
 }
 
+static inline int is_power_of_2(unsigned int val)
+{
+       return (val != 0 && ((val & (val - 1)) == 0));
+}
+
 static unsigned int get_next_buflen(struct thread_data *td, struct io_u *io_u)
 {
        const int ddir = io_u->ddir;
        unsigned int buflen = buflen; /* silence dumb gcc warning */
+       unsigned int minbs, maxbs;
        long r;
 
-       if (td->o.min_bs[ddir] == td->o.max_bs[ddir])
-               buflen = td->o.min_bs[ddir];
+       minbs = td->o.min_bs[ddir];
+       maxbs = td->o.max_bs[ddir];
+
+       if (minbs == maxbs)
+               buflen = minbs;
        else {
                r = os_random_long(&td->bsrange_state);
                if (!td->o.bssplit_nr) {
-                       buflen = (unsigned int)
-                                       (1 + (double) (td->o.max_bs[ddir] - 1)
-                                       * r / (OS_RAND_MAX + 1.0));
+                       buflen = 1 + (unsigned int) ((double) maxbs *
+                                       (r / (OS_RAND_MAX + 1.0)));
+                       if (buflen < minbs)
+                               buflen = minbs;
                } else {
                        long perc = 0;
                        unsigned int i;
@@ -251,20 +260,18 @@ static unsigned int get_next_buflen(struct thread_data *td, struct io_u *io_u)
 
                                buflen = bsp->bs;
                                perc += bsp->perc;
-                               if (r <= ((LONG_MAX / 100L) * perc))
+                               if (r <= ((OS_RAND_MAX / 100L) * perc))
                                        break;
                        }
                }
-               if (!td->o.bs_unaligned) {
-                       buflen = (buflen + td->o.min_bs[ddir] - 1)
-                                       & ~(td->o.min_bs[ddir] - 1);
-               }
+               if (!td->o.bs_unaligned && is_power_of_2(minbs))
+                       buflen = (buflen + minbs - 1) & ~(minbs - 1);
        }
 
        if (io_u->offset + buflen > io_u->file->real_file_size) {
                dprint(FD_IO, "lower buflen %u -> %u (ddir=%d)\n", buflen,
-                                               td->o.min_bs[ddir], ddir);
-               buflen = td->o.min_bs[ddir];
+                                               minbs, ddir);
+               buflen = minbs;
        }
 
        return buflen;