Fix skewed latencies for rate IOPS
- when -rate_iops is specified, FIO periodically calls usleep() to limit IOPS
- Before usleep(), FIO always wait until the completion of all pending I/O
- For all I/O completions, FIO shows erroneous behavior of logging their
latency, with that of the longest latency IO sample.
- w/ QD=8/ mixed R:W=33:66, up to 7 samples may get false latency log when
waiting all I/O completions => False report of latency distribution
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/io_u.c b/io_u.c
index e474b48..7941a6d 100644
--- a/io_u.c
+++ b/io_u.c
@@ -531,10 +531,10 @@
* io's that have been actually submitted to an async engine,
* and cur_depth is meaningless for sync engines.
*/
- if (td->io_u_in_flight) {
+ while (td->io_u_in_flight) {
int fio_unused ret;
- ret = io_u_queued_complete(td, td->io_u_in_flight, NULL);
+ ret = io_u_queued_complete(td, 1, NULL);
}
fio_gettime(&t, NULL);