Fix bug where measurements were not printed in the correct order when steady state...

ss->head points to the beginning of the buffer up through the point where the buffer is filled for the first time. afterwards, when a new element is added, ss->head is advanced to point to the second element in the buffer. if steady state is attained upon adding a new element, ss->head is not advanced so it actually does point to the head of the buffer.

diff --git a/stat.c b/stat.c
index 68a4a27609c5fcbec66b0fe55dda7c28f95120a0..4bfacf71dc7dcce0dc48bb2ba39c33475aadaa7c 100644 (file)
--- a/stat.c
+++ b/stat.c
@@ -1262,7 +1262,7 @@ static struct json_object *show_thread_status_json(struct thread_stat *ts,
                struct steadystate_data *ss = ts->ss;
                unsigned long long sum_iops, sum_bw;
                double mean_iops, mean_bw;
-               int i, x;
+               int i, j, k;
                char ss_buf[64];
 
                snprintf(ss_buf, sizeof(ss_buf), "%s%s:%f%s",
@@ -1287,12 +1287,23 @@ static struct json_object *show_thread_status_json(struct thread_stat *ts,
                json_object_add_value_object(tmp, "data", data);
                bw = json_create_array();
                iops = json_create_array();
+
+               /*
+               ** if ss was attained or the buffer is not full,
+               ** ss->head points to the first element in the list.
+               ** otherwise it actually points to the second element
+               ** in the list
+               */
+               if (ss->attained || ss->sum_y == 0)
+                       j = ss->head;
+               else
+                       j = ss->head == 0 ? ss->dur - 1 : ss->head - 1;
                for (i = 0, sum_iops = 0, sum_bw = 0; i < ss->dur; i++) {
-                       x = (ss->head + i) % ss->dur;
-                       sum_bw += ss->bw_data[x];
-                       sum_iops += ss->iops_data[x];
-                       json_array_add_value_int(bw, ss->bw_data[x]);
-                       json_array_add_value_int(iops, ss->iops_data[x]);
+                       k = (j + i) % ss->dur;
+                       sum_bw += ss->bw_data[k];
+                       sum_iops += ss->iops_data[k];
+                       json_array_add_value_int(bw, ss->bw_data[k]);
+                       json_array_add_value_int(iops, ss->iops_data[k]);
                }
                mean_bw = (double) sum_bw / ss->dur;
                mean_iops = (double) sum_iops / ss->dur;