[PATCH] blkparse: improve skip detection / logging

[blktrace.git] / blkparse.c

diff --git a/blkparse.c b/blkparse.c
index 4e02111f0d1c9c6b225399a7bac725545e727fb1..4a603d26eb6d2217379758c9ad50b325cb29cf93 100644 (file)
--- a/blkparse.c
+++ b/blkparse.c
@@ -37,6 +37,11 @@
 
 static char blkparse_version[] = "0.99";
 
+struct skip_info {
+       unsigned long start, end;
+       struct skip_info *prev, *next;
+};
+
 struct per_dev_info {
        dev_t dev;
        char *name;
@@ -63,6 +68,8 @@ struct per_dev_info {
        unsigned int cpu_map_max;
 
        struct per_cpu_info *cpus;
+       struct skip_info *skips_head;
+       struct skip_info *skips_tail;
 };
 
 struct per_process_info {
@@ -258,6 +265,95 @@ static volatile int done;
 #define CPU_IDX(cpu)   ((cpu) / CPUS_PER_LONG)
 #define CPU_BIT(cpu)   ((cpu) & (CPUS_PER_LONG - 1))
 
+static void insert_skip(struct per_dev_info *pdi, unsigned long start,
+                       unsigned long end)
+{
+       struct skip_info *sip;
+
+       for (sip = pdi->skips_tail; sip != NULL; sip = sip->prev) {
+               if (end == (sip->start - 1)) {
+                       sip->start = start;
+                       return;
+               } else if (start == (sip->end + 1)) {
+                       sip->end = end;
+                       return;
+               }
+       }
+
+       sip = malloc(sizeof(struct skip_info));
+       sip->start = start;
+       sip->end = end;
+       sip->prev = sip->next = NULL;
+       if (pdi->skips_tail == NULL)
+               pdi->skips_head = pdi->skips_tail = sip;
+       else {
+               sip->prev = pdi->skips_tail;
+               pdi->skips_tail->next = sip;
+               pdi->skips_tail = sip;
+       }
+}
+
+static void remove_sip(struct per_dev_info *pdi, struct skip_info *sip)
+{
+       if (sip->prev == NULL) {
+               if (sip->next == NULL)
+                       pdi->skips_head = pdi->skips_tail = NULL;
+               else {
+                       pdi->skips_head = sip->next;
+                       sip->next->prev = NULL;
+               }
+       } else if (sip->next == NULL) {
+               pdi->skips_tail = sip->prev;
+               sip->prev->next = NULL;
+       } else {
+               sip->prev->next = sip->next;
+               sip->next->prev = sip->prev;
+       }
+
+       sip->prev = sip->next = NULL;
+       free(sip);
+}
+
+#define IN_SKIP(sip,seq) (((sip)->start <= (seq)) && ((seq) <= sip->end))
+static int check_current_skips(struct per_dev_info *pdi, unsigned long seq)
+{
+       struct skip_info *sip;
+
+       for (sip = pdi->skips_tail; sip != NULL; sip = sip->prev) {
+               if (IN_SKIP(sip,seq)) {
+                       if (sip->start == seq) {
+                               if (sip->end == seq)
+                                       remove_sip(pdi,sip);
+                               else
+                                       sip->start += 1;
+                       } else if (sip->end == seq)
+                               sip->end -= 1;
+                       else {
+                               sip->end = seq - 1;
+                               insert_skip(pdi,seq+1,sip->end);
+                       }
+                       return 1;
+               }
+       }
+       return 0;
+}
+
+static void collect_pdi_skips(struct per_dev_info *pdi)
+{
+       struct skip_info *sip;
+
+       pdi->skips = 0;
+       pdi->seq_skips = 0;
+       for (sip = pdi->skips_tail; sip != NULL; sip = sip->prev) {
+               pdi->skips += 1;
+               pdi->seq_skips += (sip->end - sip->start + 1);
+               if (verbose)
+                       fprintf(stderr, "(%d,%d): skipping %lu -> %lu\n",
+                               MAJOR(pdi->dev), MINOR(pdi->dev),
+                               sip->start, sip->end);
+       }
+}
+
 static void cpu_mark_online(struct per_dev_info *pdi, unsigned int cpu)
 {
        if (cpu >= pdi->cpu_map_max || !pdi->cpu_map) {
@@ -458,7 +554,7 @@ static struct trace *trace_rb_find(dev_t device, unsigned long sequence,
 
                while (((n = rb_next(prev)) != NULL) && max--) {
                        __t = rb_entry(n, struct trace, rb_node);
-                       
+
                        if (__t->bit->device == device &&
                            __t->bit->sequence == sequence)
                                return __t;
@@ -466,7 +562,7 @@ static struct trace *trace_rb_find(dev_t device, unsigned long sequence,
                        prev = n;
                }
        }
-                       
+
        return NULL;
 }
 
@@ -781,6 +877,9 @@ static struct per_dev_info *get_dev_info(dev_t dev)
        pdi->last_read_time = 0;
        memset(&pdi->rb_last, 0, sizeof(pdi->rb_last));
        pdi->rb_last_entries = 0;
+
+       pdi->skips_head = pdi->skips_tail = NULL;
+
        return pdi;
 }
 
@@ -1308,12 +1407,11 @@ static void show_device_and_cpu_stats(void)
                        rrate, wrate);
                fprintf(ofp, "Events (%s): %'Lu entries\n",
                        get_dev_name(pdi, line, sizeof(line)), pdi->events);
-               fprintf(ofp, "Skips: %'lu forward (%'llu - %5.1lf%%) %'lu backward (%'llu - %5.1lf%%)\n",
+
+               collect_pdi_skips(pdi);
+               fprintf(ofp, "Skips: %'lu forward (%'llu - %5.1lf%%)\n",
                        pdi->skips,pdi->seq_skips,
                        100.0 * ((double)pdi->seq_skips /
-                               (double)(pdi->events + pdi->seq_skips)),
-                       pdi->nskips,pdi->seq_nskips,
-                       100.0 * ((double)pdi->seq_nskips /
                                (double)(pdi->events + pdi->seq_skips)));
        }
 }
@@ -1501,7 +1599,7 @@ static int check_sequence(struct per_dev_info *pdi, struct trace *t, int force)
        unsigned long expected_sequence = pdi->last_sequence + 1;
        struct blk_io_trace *bit = t->bit;
        struct trace *__t;
-       
+
        if (!expected_sequence) {
                /*
                 * 1 should be the first entry, just allow it
@@ -1530,18 +1628,10 @@ static int check_sequence(struct per_dev_info *pdi, struct trace *t, int force)
                return 1;
        } else {
 skip:
-               if (verbose) {
-                       fprintf(stderr, "(%d,%d): skipping %lu -> %u\n",
-                               MAJOR(pdi->dev), MINOR(pdi->dev),
-                               pdi->last_sequence, bit->sequence);
-               }
-               if (bit->sequence > pdi->last_sequence) {
-                       pdi->skips++;
-                       pdi->seq_skips += (bit->sequence - pdi->last_sequence);
-               } else {
-                       pdi->nskips++;
-                       pdi->seq_nskips += (pdi->last_sequence - bit->sequence);
-               }
+               if (check_current_skips(pdi,bit->sequence))
+                       return 0;
+
+               insert_skip(pdi,expected_sequence,bit->sequence-1);
                return 0;
        }
 }