- rate = (td->this_io_bytes[ddir] - td->stat_io_bytes[ddir]) *
- 1000 / spent / 1024;
- add_stat_sample(&ts->bw_stat[ddir], rate);
+ /*
+ * Compute both read and write rates for the interval.
+ */
+ for (ddir = DDIR_READ; ddir <= DDIR_WRITE; ddir++) {
+ uint64_t delta;
+
+ delta = td->this_io_bytes[ddir] - td->stat_io_bytes[ddir];
+ if (!delta)
+ continue; /* No entries for interval */
+
+ rate = delta * 1000 / spent / 1024;
+ add_stat_sample(&ts->bw_stat[ddir], rate);