[PATCH] blkparse: improve skip detection

diff --git a/blkparse.c b/blkparse.c
index 70516189b3d0066f9f700c6ae96b4db3e7978fac..12cb8ed64885a295f6accbe55de1cd591540e31b 100644 (file)
--- a/blkparse.c
+++ b/blkparse.c
@@ -153,7 +153,6 @@ struct trace {
        struct blk_io_trace *bit;
        struct rb_node rb_node;
        struct trace *next;
-       int skipped;
 };
 
 static struct rb_root rb_sort_root;
@@ -438,7 +437,9 @@ static void log_track_frontmerge(struct blk_io_trace *t)
 
        iot = __find_track(t->device, t->sector + (t->bytes >> 9));
        if (!iot) {
-               fprintf(stderr, "failed to find mergeable event\n");
+               fprintf(stderr, "merge not found for (%d,%d): %llu\n",
+                       MAJOR(t->device), MINOR(t->device),
+                       t->sector + (t->bytes >> 9));
                return;
        }
 
@@ -458,7 +459,6 @@ static void log_track_getrq(struct blk_io_trace *t)
        iot->allocation_time = t->time;
 }
 
-
 /*
  * return time between rq allocation and insertion
  */
@@ -472,6 +472,10 @@ static unsigned long long log_track_insert(struct blk_io_trace *t)
 
        iot = find_track(t->pid, t->comm, t->device, t->sector);
        iot->queue_time = t->time;
+
+       if (!iot->allocation_time)
+               return -1;
+
        elapsed = iot->queue_time - iot->allocation_time;
 
        if (per_process_stats) {
@@ -500,7 +504,8 @@ static unsigned long long log_track_issue(struct blk_io_trace *t)
 
        iot = __find_track(t->device, t->sector);
        if (!iot) {
-               fprintf(stderr, "failed to find issue event\n");
+               fprintf(stderr, "issue not found for (%d,%d): %llu\n",
+                       MAJOR(t->device), MINOR(t->device), t->sector);
                return -1;
        }
 
@@ -533,7 +538,8 @@ static unsigned long long log_track_complete(struct blk_io_trace *t)
 
        iot = __find_track(t->device, t->sector);
        if (!iot) {
-               fprintf(stderr, "failed to find complete event\n");
+               fprintf(stderr, "complete not found for (%d,%d): %llu\n",
+                       MAJOR(t->device), MINOR(t->device), t->sector);
                return -1;
        }
 
@@ -1250,26 +1256,28 @@ static void show_entries_rb(int force)
                 * on SMP systems. to prevent stalling on lost events,
                 * only allow an event to skip us a few times
                 */
-               if (bit->sequence > (pdi->last_sequence + 1) && !force) {
-                       struct trace *__t;
-
-                       /*
-                        * the wanted sequence is really there, continue
-                        * because this means that the log time is earlier
-                        * on the trace we have now
-                        */
-                       __t = trace_rb_find(pdi->id, pdi->last_sequence + 1);
-                       if (__t)
-                               goto ok;
-
-                       if (t->skipped < 5) {
-                               t->skipped++;
-                               break;
-                       } else
+               if (bit->sequence != (pdi->last_sequence + 1)) {
+                       if (!force) {
+                               struct trace *__t;
+
+                               /*
+                                * the wanted sequence is really there,
+                                * continue because this means that the
+                                * log time is earlier on the trace we have
+                                * now
+                                */
+                               __t = trace_rb_find(pdi->id,
+                                                       pdi->last_sequence + 1);
+                               if (__t == NULL)
+                                       break;
+                       } else {
+                               fprintf(stderr, "(%d,%d): skipping %lu -> %u\n",
+                                       MAJOR(pdi->id), MINOR(pdi->id),
+                                       pdi->last_sequence, bit->sequence);
                                pdi->skips++;
+                       }
                }
 
-ok:
                if (!force && bit->time > last_allowed_time)
                        break;