io_size vs. time_based discrepancy

I'm witnessing an annoying discrepancy between the outcome of the same
job when being run as io_size-based vs. time_based. In the former
mode, the job does exactly what I want it to do, writing the
prescribed amount of data randomly w/o being concerned whether that
total bytes written is in any way related to the target file size.

On the contrary, in the latter mode that same job, after writing the
file's size worth of bytes, resets random generator and essentially
restarts the just completed loop. The offending code is below, and the
suggested fix brings back home the io_size-like behavior when running
time-based. Nonetheless, I'm in doubt regarding whether the do_io loop
break-out below was intended to support the designed behavior (looks
unlikely to me, as looping like that is produced by the 'loops'
option, although time_based definition under HOWTO is rather unclear
in this regard) or is a bug worth fixing.

Regards,
Andrey

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

diff --git a/backend.c b/backend.c
index 1560749618a5a91ed6152849cba8f9124b73dc16..224736f4c963dcef68db671b39b83ec9ed763758 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -868,7 +868,7 @@ static uint64_t do_io(struct thread_data *td)
                if (flow_threshold_exceeded(td))
                        continue;
 
-               if (bytes_issued >= total_bytes)
+               if (!td->o.time_based && bytes_issued >= total_bytes)
                        break;
 
                io_u = get_io_u(td);