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-rw-r--r--runtime/stat-common.c199
1 files changed, 122 insertions, 77 deletions
diff --git a/runtime/stat-common.c b/runtime/stat-common.c
index 9ca045c9..80ced30d 100644
--- a/runtime/stat-common.c
+++ b/runtime/stat-common.c
@@ -12,6 +12,28 @@
#define _STAT_COMMON_C_
#include "stat.h"
+static int _stp_stat_calc_buckets(int stop, int start, int interval)
+{
+ int buckets;
+
+ if (interval == 0) {
+ _stp_warn("histogram: interval cannot be zero.\n");
+ return 0;
+ }
+ buckets = (stop - start) / interval;
+ if ((stop - start) % interval)
+ buckets++;
+
+ if (buckets > STP_MAX_BUCKETS || buckets <= 0) {
+ _stp_warn("histogram: Number of buckets must be between 1 and %d\n"
+ "Number_of_buckets = (stop - start) / interval.\n"
+ "Please adjust your start, stop, and interval values.\n",
+ STP_MAX_BUCKETS);
+ return 0;
+ }
+ return buckets;
+}
+
static int needed_space(int64_t v)
{
int space = 0;
@@ -39,57 +61,72 @@ static void reprint (int num, char *s)
}
}
-/* implements a log base 2 function, or Most Significant Bit */
-/* with bits from 1 (lsb) to 64 (msb) */
-/* msb64(0) = 0 */
-/* msb64(1) = 1 */
-/* msb64(8) = 4 */
-/* msb64(512) = 10 */
+/* Given a bucket number for a log histogram, return the value. */
+static int64_t _stp_bucket_to_val(int num)
+{
+ if (num == HIST_LOG_BUCKET0)
+ return 0;
+ if (num < HIST_LOG_BUCKET0) {
+ int64_t val = 0x8000000000000000LL;
+ return val >> num;
+ } else
+ return 1LL << (num - HIST_LOG_BUCKET0 - 1);
+}
-static int msb64(int64_t val)
+/* Implements a log base 2 function. Returns a bucket
+ * number from 0 to HIST_LOG_BUCKETS.
+ */
+static int _stp_val_to_bucket(int64_t val)
{
- int res = 64;
-
- if (val == 0)
- return 0;
-
- /* shortcut. most values will be 16-bit */
- if (val & 0xffffffffffff0000ull) {
- if (!(val & 0xffffffff00000000ull)) {
- val <<= 32;
- res -= 32;
- }
-
- if (!(val & 0xffff000000000000ull)) {
- val <<= 16;
- res -= 16;
- }
- } else {
- val <<= 48;
- res -= 48;
- }
-
- if (!(val & 0xff00000000000000ull)) {
- val <<= 8;
- res -= 8;
- }
-
- if (!(val & 0xf000000000000000ull)) {
- val <<= 4;
- res -= 4;
- }
-
- if (!(val & 0xc000000000000000ull)) {
- val <<= 2;
- res -= 2;
- }
-
- if (!(val & 0x8000000000000000ull)) {
- val <<= 1;
- res -= 1;
- }
-
- return res;
+ int neg = 0, res = HIST_LOG_BUCKETS;
+
+ if (val == 0)
+ return HIST_LOG_BUCKET0;
+
+ if (val < 0) {
+ val = -val;
+ neg = 1;
+ }
+
+ /* shortcut. most values will be 16-bit */
+ if (unlikely(val & 0xffffffffffff0000ull)) {
+ if (!(val & 0xffffffff00000000ull)) {
+ val <<= 32;
+ res -= 32;
+ }
+
+ if (!(val & 0xffff000000000000ull)) {
+ val <<= 16;
+ res -= 16;
+ }
+ } else {
+ val <<= 48;
+ res -= 48;
+ }
+
+ if (!(val & 0xff00000000000000ull)) {
+ val <<= 8;
+ res -= 8;
+ }
+
+ if (!(val & 0xf000000000000000ull)) {
+ val <<= 4;
+ res -= 4;
+ }
+
+ if (!(val & 0xc000000000000000ull)) {
+ val <<= 2;
+ res -= 2;
+ }
+
+ if (!(val & 0x8000000000000000ull)) {
+ val <<= 1;
+ res -= 1;
+ }
+ if (neg)
+ res = HIST_LOG_BUCKETS - res;
+
+ return res;
}
#ifndef HIST_WIDTH
@@ -119,8 +156,14 @@ static void _stp_stat_print_histogram (Hist st, stat *sd)
/* Touch up the bucket margin to show up to two zero-slots on
either side of the data range, seems aesthetically pleasant. */
for (i = 0; i < 2; i++) {
- if (low_bucket > 0)
- low_bucket--;
+ if (st->type == HIST_LOG) {
+ /* For log histograms, don't go negative */
+ /* unless there are negative values. */
+ if (low_bucket != HIST_LOG_BUCKET0 && low_bucket > 0)
+ low_bucket--;
+ } else
+ if (low_bucket > 0)
+ low_bucket--;
if (high_bucket < (st->buckets-1))
high_bucket++;
@@ -138,8 +181,12 @@ static void _stp_stat_print_histogram (Hist st, stat *sd)
cnt_space = needed_space (max);
if (st->type == HIST_LINEAR)
val_space = needed_space (st->start + st->interval * high_bucket);
- else
- val_space = needed_space (((int64_t)1) << high_bucket);
+ else {
+ int tmp = needed_space(_stp_bucket_to_val(high_bucket));
+ val_space = needed_space(_stp_bucket_to_val(low_bucket));
+ if (tmp > val_space)
+ val_space = tmp;
+ }
//dbug ("max=%lld scale=%d val_space=%d\n", max, scale, val_space);
/* print header */
@@ -153,30 +200,22 @@ static void _stp_stat_print_histogram (Hist st, stat *sd)
_stp_print("value |");
reprint (HIST_WIDTH, "-");
_stp_print(" count\n");
- if (st->type == HIST_LINEAR)
- val = st->start;
- else
- val = 0;
- for (i = 0; i < st->buckets; i++) {
- if (i >= low_bucket && i <= high_bucket) {
- reprint (val_space - needed_space(val), " ");
- _stp_printf("%lld", val);
- _stp_print(" |");
-
- /* v = s->histogram[i] / scale; */
- v = sd->histogram[i];
- do_div (v, scale);
-
- reprint (v, "@");
- reprint (HIST_WIDTH - v + 1 + cnt_space - needed_space(sd->histogram[i]), " ");
- _stp_printf ("%lld\n", sd->histogram[i]);
- }
- if (st->type == HIST_LINEAR)
- val += st->interval;
- else if (val == 0)
- val = 1;
+ for (i = low_bucket; i <= high_bucket; i++) {
+ if (st->type == HIST_LINEAR)
+ val = st->start + i * st->interval;
else
- val *= 2;
+ val = _stp_bucket_to_val(i);
+ reprint (val_space - needed_space(val), " ");
+ _stp_printf("%lld", val);
+ _stp_print(" |");
+
+ /* v = s->histogram[i] / scale; */
+ v = sd->histogram[i];
+ do_div (v, scale);
+
+ reprint (v, "@");
+ reprint (HIST_WIDTH - v + 1 + cnt_space - needed_space(sd->histogram[i]), " ");
+ _stp_printf ("%lld\n", sd->histogram[i]);
}
_stp_print_char('\n');
_stp_print_flush();
@@ -231,18 +270,24 @@ static void __stp_stat_add (Hist st, stat *sd, int64_t val)
}
switch (st->type) {
case HIST_LOG:
- n = msb64 (val);
+ n = _stp_val_to_bucket (val);
if (n >= st->buckets)
n = st->buckets - 1;
sd->histogram[n]++;
break;
case HIST_LINEAR:
val -= st->start;
+
+ /* underflow */
if (val < 0)
val = 0;
+
do_div (val, st->interval);
+
+ /* overflow */
if (val >= st->buckets)
val = st->buckets - 1;
+
sd->histogram[val]++;
default:
break;
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