eta: Avoid adjustements to a negative value

In the case of zonemode=strided job with both zone_size and zone_skip
specified, thread_eta() calculates the upper bound of the number of
zones that will be processed, including skipped bytes between zones
(zone_skip). Adjusting bytes_total (i.e. total_io_size) by substracting
this number of zones times the amount of skipped bytes can result in
a negative value for bytes_total (a large number of bytes) when for
example the job operates on an entire disk with a capacity that is not
divisible exactly by zone_size+zone_skip or if the options --size is
used to limit the I/O range. In such case, use the lower bound of the
number of zones to obtain a better approximation of the job eta.

Additionnally, if --io_size was specified, bytes_total will indicate
this exact value, so adjusting that value for zonemode != none is not
necessary.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/eta.c b/eta.c
index 970a67dfd0ac8d6672758b99d528f32526f26e4e..b69dd19439712f3e597696dfffb0cdc57dcf5ff9 100644 (file)
--- a/eta.c
+++ b/eta.c
@@ -177,12 +177,27 @@ static unsigned long thread_eta(struct thread_data *td)
                bytes_total = td->fill_device_size;
        }
 
                bytes_total = td->fill_device_size;
        }
 

-       if (td->o.zone_size && td->o.zone_skip && bytes_total) {
+       /*
+        * If io_size is set, bytes_total is an exact value that does not need
+        * adjustment.
+        */
+       if (td->o.zone_size && td->o.zone_skip && bytes_total &&
+           !fio_option_is_set(&td->o, io_size)) {

                unsigned int nr_zones;
                uint64_t zone_bytes;
 
                unsigned int nr_zones;
                uint64_t zone_bytes;
 

-               zone_bytes = bytes_total + td->o.zone_size + td->o.zone_skip;
-               nr_zones = (zone_bytes - 1) / (td->o.zone_size + td->o.zone_skip);
+               /*
+                * Calculate the upper bound of the number of zones that will
+                * be processed, including skipped bytes between zones. If this
+                * is larger than total_io_size (e.g. when --io_size or --size
+                * specify a small value), use the lower bound to avoid
+                * adjustments to a negative value that would result in a very
+                * large bytes_total and an incorrect eta.
+                */
+               zone_bytes = td->o.zone_size + td->o.zone_skip;
+               nr_zones = (bytes_total + zone_bytes - 1) / zone_bytes;
+               if (bytes_total < nr_zones * td->o.zone_skip)
+                       nr_zones = bytes_total / zone_bytes;

                bytes_total -= nr_zones * td->o.zone_skip;
        }
 
                bytes_total -= nr_zones * td->o.zone_skip;
        }