diff --git a/src/utils_latency.c b/src/utils_latency.c
index 96ce8e31e64c4289a7f2c0fd8ce11e8765fb3fed..12fc9b82dfa6e1e3817184d6027ef7f4b724fbee 100644 (file)
--- a/src/utils_latency.c
+++ b/src/utils_latency.c
/**
* collectd - src/utils_latency.c
/**
* collectd - src/utils_latency.c
- * Copyright (C) 2013 Florian Forster
+ * Copyright (C) 2013 Florian Forster
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
#include "common.h"
#include <math.h>
#include "common.h"
#include <math.h>
+#include <limits.h>
+
+#ifndef LLONG_MAX
+# define LLONG_MAX 9223372036854775807LL
+#endif
#ifndef HISTOGRAM_NUM_BINS
# define HISTOGRAM_NUM_BINS 1000
#endif
#ifndef HISTOGRAM_NUM_BINS
# define HISTOGRAM_NUM_BINS 1000
#endif
-static const int HISTOGRAM_DEFAULT_BIN_WIDTH = 1;
+#ifndef HISTOGRAM_DEFAULT_BIN_WIDTH
+/* 1048576 = 2^20 ^= 1/1024 s */
+# define HISTOGRAM_DEFAULT_BIN_WIDTH 1048576
+#endif
struct latency_counter_s
{
struct latency_counter_s
{
cdtime_t min;
cdtime_t max;
cdtime_t min;
cdtime_t max;
- int bin_width;
+ cdtime_t bin_width;
int histogram[HISTOGRAM_NUM_BINS];
};
int histogram[HISTOGRAM_NUM_BINS];
};
*
* So, if the required bin width is 300, then new bin width will be 512 as it is
* the next nearest power of 2.
*
* So, if the required bin width is 300, then new bin width will be 512 as it is
* the next nearest power of 2.
-*
*/
*/
-void change_bin_width (latency_counter_t *lc, size_t val) /* {{{ */
+void change_bin_width (latency_counter_t *lc, cdtime_t latency) /* {{{ */
{
{
- int i=0;
/* This function is called because the new value is above histogram's range.
* First find the required bin width:
* requiredBinWidth = (value + 1) / numBins
* then get the next nearest power of 2
* newBinWidth = 2^(ceil(log2(requiredBinWidth)))
*/
/* This function is called because the new value is above histogram's range.
* First find the required bin width:
* requiredBinWidth = (value + 1) / numBins
* then get the next nearest power of 2
* newBinWidth = 2^(ceil(log2(requiredBinWidth)))
*/
- double required_bin_width = (double)(val + 1) / HISTOGRAM_NUM_BINS;
- double required_bin_width_logbase2 = log(required_bin_width) / log(2.0);
- int new_bin_width = (int)(pow(2.0, ceil( required_bin_width_logbase2)));
- int old_bin_width = lc->bin_width;
+ double required_bin_width = ((double) (latency + 1)) / ((double) HISTOGRAM_NUM_BINS);
+ double required_bin_width_logbase2 = log (required_bin_width) / log (2.0);
+ cdtime_t new_bin_width = (cdtime_t) (pow (2.0, ceil (required_bin_width_logbase2)) + .5);
+ cdtime_t old_bin_width = lc->bin_width;
+
lc->bin_width = new_bin_width;
lc->bin_width = new_bin_width;
- /*
- * bin width has been increased, now iterate through all bins and move the
- * old bin's count to new bin.
- */
+ /* bin_width has been increased, now iterate through all bins and move the
+ * old bin's count to new bin. */
if (lc->num > 0) // if the histogram has data then iterate else skip
{
if (lc->num > 0) // if the histogram has data then iterate else skip
{
- double width_change_ratio = old_bin_width / new_bin_width;
- for (i=0; i<HISTOGRAM_NUM_BINS; i++)
+ double width_change_ratio = ((double) old_bin_width) / ((double) new_bin_width);
+ size_t i;
+
+ for (i = 0; i < HISTOGRAM_NUM_BINS; i++)
{
{
- int new_bin = (int)(i * width_change_ratio);
+ size_t new_bin = (size_t) (((double) i) * width_change_ratio);
if (i == new_bin)
continue;
if (i == new_bin)
continue;
+ assert (new_bin < i);
+
lc->histogram[new_bin] += lc->histogram[i];
lc->histogram[i] = 0;
}
lc->histogram[new_bin] += lc->histogram[i];
lc->histogram[i] = 0;
}
- DEBUG("utils_latency: change_bin_width: fixed all bins");
}
}
- DEBUG("utils_latency: change_bin_width: val-[%zu], oldBinWidth-[%d], "
- "newBinWidth-[%d], required_bin_width-[%f], "
- "required_bin_width_logbase2-[%f]",
- val, old_bin_width, new_bin_width, required_bin_width,
- required_bin_width_logbase2);
-
+ DEBUG("utils_latency: change_bin_width: latency = %.3f; "
+ "old_bin_width = %.3f; new_bin_width = %.3f;",
+ CDTIME_T_TO_DOUBLE (latency),
+ CDTIME_T_TO_DOUBLE (old_bin_width),
+ CDTIME_T_TO_DOUBLE (new_bin_width));
} /* }}} void change_bin_width */
latency_counter_t *latency_counter_create () /* {{{ */
} /* }}} void change_bin_width */
latency_counter_t *latency_counter_create () /* {{{ */
lc = malloc (sizeof (*lc));
if (lc == NULL)
return (NULL);
lc = malloc (sizeof (*lc));
if (lc == NULL)
return (NULL);
+ memset (lc, 0, sizeof (*lc));
latency_counter_reset (lc);
lc->bin_width = HISTOGRAM_DEFAULT_BIN_WIDTH;
latency_counter_reset (lc);
lc->bin_width = HISTOGRAM_DEFAULT_BIN_WIDTH;
void latency_counter_add (latency_counter_t *lc, cdtime_t latency) /* {{{ */
{
void latency_counter_add (latency_counter_t *lc, cdtime_t latency) /* {{{ */
{
- size_t latency_ms;
+ cdtime_t bin;
- if ((lc == NULL) || (latency == 0))
+ if ((lc == NULL) || (latency == 0) || (latency > ((cdtime_t) LLONG_MAX)))
return;
lc->sum += latency;
return;
lc->sum += latency;
/* A latency of _exactly_ 1.0 ms should be stored in the buffer 0, so
* subtract one from the cdtime_t value so that exactly 1.0 ms get sorted
* accordingly. */
/* A latency of _exactly_ 1.0 ms should be stored in the buffer 0, so
* subtract one from the cdtime_t value so that exactly 1.0 ms get sorted
* accordingly. */
- latency_ms = (size_t) CDTIME_T_TO_MS (latency - 1);
-
- int bin = (int)(latency_ms / lc->bin_width);
+ bin = (latency - 1) / lc->bin_width;
if (bin >= HISTOGRAM_NUM_BINS)
{
if (bin >= HISTOGRAM_NUM_BINS)
{
- change_bin_width(lc, latency_ms);
- bin = (int)(latency_ms / lc->bin_width);
+ change_bin_width (lc, latency);
+ bin = (latency - 1) / lc->bin_width;
if (bin >= HISTOGRAM_NUM_BINS)
{
if (bin >= HISTOGRAM_NUM_BINS)
{
- ERROR("utils_latency: latency_counter_add: Invalid bin %d", bin);
+ ERROR ("utils_latency: latency_counter_add: Invalid bin: %"PRIu64, bin);
return;
}
}
return;
}
}
if (lc == NULL)
return;
if (lc == NULL)
return;
- int bin_width = lc->bin_width;
+ cdtime_t bin_width = lc->bin_width;
memset (lc, 0, sizeof (*lc));
/* preserve bin width */
memset (lc, 0, sizeof (*lc));
/* preserve bin width */
{
double average;
{
double average;
- if (lc == NULL)
+ if ((lc == NULL) || (lc->num == 0))
return (0);
average = CDTIME_T_TO_DOUBLE (lc->sum) / ((double) lc->num);
return (DOUBLE_TO_CDTIME_T (average));
} /* }}} cdtime_t latency_counter_get_average */
return (0);
average = CDTIME_T_TO_DOUBLE (lc->sum) / ((double) lc->num);
return (DOUBLE_TO_CDTIME_T (average));
} /* }}} cdtime_t latency_counter_get_average */
-cdtime_t latency_counter_get_percentile (latency_counter_t *lc,
+cdtime_t latency_counter_get_percentile (latency_counter_t *lc, /* {{{ */
double percent)
{
double percent_upper;
double percent_lower;
double percent)
{
double percent_upper;
double percent_lower;
- double ms_upper;
- double ms_lower;
- double ms_interpolated;
+ double p;
+ cdtime_t latency_lower;
+ cdtime_t latency_interpolated;
int sum;
size_t i;
int sum;
size_t i;
- if ((lc == NULL) || !((percent > 0.0) && (percent < 100.0)))
+ if ((lc == NULL) || (lc->num == 0) || !((percent > 0.0) && (percent < 100.0)))
return (0);
/* Find index i so that at least "percent" events are within i+1 ms. */
return (0);
/* Find index i so that at least "percent" events are within i+1 ms. */
assert (percent_upper >= percent);
assert (percent_lower < percent);
assert (percent_upper >= percent);
assert (percent_lower < percent);
- ms_upper = (double) ( (i + 1) * lc->bin_width );
- ms_lower = (double) ( i * lc->bin_width );
if (i == 0)
if (i == 0)
- return (MS_TO_CDTIME_T (ms_upper));
+ return (lc->bin_width);
+
+ latency_lower = ((cdtime_t) i) * lc->bin_width;
+ p = (percent - percent_lower) / (percent_upper - percent_lower);
- ms_interpolated = (((percent_upper - percent) * ms_lower)
- + ((percent - percent_lower) * ms_upper))
- / (percent_upper - percent_lower);
+ latency_interpolated = latency_lower
+ + DOUBLE_TO_CDTIME_T (p * CDTIME_T_TO_DOUBLE (lc->bin_width));
- return (MS_TO_CDTIME_T (ms_interpolated));
+ DEBUG ("latency_counter_get_percentile: latency_interpolated = %.3f",
+ CDTIME_T_TO_DOUBLE (latency_interpolated));
+ return (latency_interpolated);
} /* }}} cdtime_t latency_counter_get_percentile */
/* vim: set sw=2 sts=2 et fdm=marker : */
} /* }}} cdtime_t latency_counter_get_percentile */
/* vim: set sw=2 sts=2 et fdm=marker : */