rbd: initialize random number generator for bench-write

Without this, the same seed is used each time, so multiple runs
of bench-write with the same parameters have the same I/O pattern.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>

diff --git a/src/rbd.cc b/src/rbd.cc
index d776ef018cdf6fbda6f50576172b63ff0849c9b6..453ab4ec8944e1eca9d92e64ee1f9ffff46b8cb2 100644 (file)
--- a/src/rbd.cc
+++ b/src/rbd.cc
@@ -879,6 +879,8 @@ static int do_bench_write(librbd::Image& image, uint64_t io_size,
   if (pattern != "rand" && pattern != "seq")
     return -EINVAL;
 
+  srand(time(NULL) % (unsigned long) -1);
+
   bufferptr bp(io_size);
   memset(bp.c_str(), rand() & 0xff, io_size);
   bufferlist bl;