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/*
* librdkafka - Apache Kafka C library
*
* Copyright (c) 2018 Magnus Edenhill
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _RDAVG_H_
#define _RDAVG_H_
#if WITH_HDRHISTOGRAM
#include "rdhdrhistogram.h"
#endif
typedef struct rd_avg_s {
struct {
int64_t maxv;
int64_t minv;
int64_t avg;
int64_t sum;
int cnt;
rd_ts_t start;
} ra_v;
mtx_t ra_lock;
int ra_enabled;
enum { RD_AVG_GAUGE,
RD_AVG_COUNTER,
} ra_type;
#if WITH_HDRHISTOGRAM
rd_hdr_histogram_t *ra_hdr;
#endif
/* Histogram results, calculated for dst in rollover().
* Will be all zeroes if histograms are not supported. */
struct {
/* Quantiles */
int64_t p50;
int64_t p75;
int64_t p90;
int64_t p95;
int64_t p99;
int64_t p99_99;
int64_t oor; /**< Values out of range */
int32_t hdrsize; /**< hdr.allocatedSize */
double stddev;
double mean;
} ra_hist;
} rd_avg_t;
/**
* @brief Add value \p v to averager \p ra.
*/
static RD_UNUSED void rd_avg_add(rd_avg_t *ra, int64_t v) {
mtx_lock(&ra->ra_lock);
if (!ra->ra_enabled) {
mtx_unlock(&ra->ra_lock);
return;
}
if (v > ra->ra_v.maxv)
ra->ra_v.maxv = v;
if (ra->ra_v.minv == 0 || v < ra->ra_v.minv)
ra->ra_v.minv = v;
ra->ra_v.sum += v;
ra->ra_v.cnt++;
#if WITH_HDRHISTOGRAM
rd_hdr_histogram_record(ra->ra_hdr, v);
#endif
mtx_unlock(&ra->ra_lock);
}
/**
* @brief Calculate the average
*/
static RD_UNUSED void rd_avg_calc(rd_avg_t *ra, rd_ts_t now) {
if (ra->ra_type == RD_AVG_GAUGE) {
if (ra->ra_v.cnt)
ra->ra_v.avg = ra->ra_v.sum / ra->ra_v.cnt;
else
ra->ra_v.avg = 0;
} else {
rd_ts_t elapsed = now - ra->ra_v.start;
if (elapsed)
ra->ra_v.avg = (ra->ra_v.sum * 1000000llu) / elapsed;
else
ra->ra_v.avg = 0;
ra->ra_v.start = elapsed;
}
}
/**
* @returns the quantile \q for \p ra, or 0 if histograms are not supported
* in this build.
*
* @remark ra will be not locked by this function.
*/
static RD_UNUSED int64_t rd_avg_quantile(const rd_avg_t *ra, double q) {
#if WITH_HDRHISTOGRAM
return rd_hdr_histogram_quantile(ra->ra_hdr, q);
#else
return 0;
#endif
}
/**
* @brief Rolls over statistics in \p src and stores the average in \p dst.
* \p src is cleared and ready to be reused.
*
* Caller must free avg internal members by calling rd_avg_destroy()
* on the \p dst.
*/
static RD_UNUSED void rd_avg_rollover(rd_avg_t *dst, rd_avg_t *src) {
rd_ts_t now;
mtx_lock(&src->ra_lock);
if (!src->ra_enabled) {
memset(dst, 0, sizeof(*dst));
dst->ra_type = src->ra_type;
mtx_unlock(&src->ra_lock);
return;
}
mtx_init(&dst->ra_lock, mtx_plain);
dst->ra_type = src->ra_type;
dst->ra_v = src->ra_v;
#if WITH_HDRHISTOGRAM
dst->ra_hdr = NULL;
dst->ra_hist.stddev = rd_hdr_histogram_stddev(src->ra_hdr);
dst->ra_hist.mean = rd_hdr_histogram_mean(src->ra_hdr);
dst->ra_hist.oor = src->ra_hdr->outOfRangeCount;
dst->ra_hist.hdrsize = src->ra_hdr->allocatedSize;
dst->ra_hist.p50 = rd_hdr_histogram_quantile(src->ra_hdr, 50.0);
dst->ra_hist.p75 = rd_hdr_histogram_quantile(src->ra_hdr, 75.0);
dst->ra_hist.p90 = rd_hdr_histogram_quantile(src->ra_hdr, 90.0);
dst->ra_hist.p95 = rd_hdr_histogram_quantile(src->ra_hdr, 95.0);
dst->ra_hist.p99 = rd_hdr_histogram_quantile(src->ra_hdr, 99.0);
dst->ra_hist.p99_99 = rd_hdr_histogram_quantile(src->ra_hdr, 99.99);
#else
memset(&dst->ra_hist, 0, sizeof(dst->ra_hist));
#endif
memset(&src->ra_v, 0, sizeof(src->ra_v));
now = rd_clock();
src->ra_v.start = now;
#if WITH_HDRHISTOGRAM
/* Adapt histogram span to fit future out of range entries
* from this period. */
if (src->ra_hdr->totalCount > 0) {
int64_t vmin = src->ra_hdr->lowestTrackableValue;
int64_t vmax = src->ra_hdr->highestTrackableValue;
int64_t mindiff, maxdiff;
mindiff = src->ra_hdr->lowestTrackableValue -
src->ra_hdr->lowestOutOfRange;
if (mindiff > 0) {
/* There were low out of range values, grow lower
* span to fit lowest out of range value + 20%. */
vmin = src->ra_hdr->lowestOutOfRange +
(int64_t)((double)mindiff * 0.2);
}
maxdiff = src->ra_hdr->highestOutOfRange -
src->ra_hdr->highestTrackableValue;
if (maxdiff > 0) {
/* There were high out of range values, grow higher
* span to fit highest out of range value + 20%. */
vmax = src->ra_hdr->highestOutOfRange +
(int64_t)((double)maxdiff * 0.2);
}
if (vmin == src->ra_hdr->lowestTrackableValue &&
vmax == src->ra_hdr->highestTrackableValue) {
/* No change in min,max, use existing hdr */
rd_hdr_histogram_reset(src->ra_hdr);
} else {
int sigfigs = (int)src->ra_hdr->significantFigures;
/* Create new hdr for adapted range */
rd_hdr_histogram_destroy(src->ra_hdr);
src->ra_hdr = rd_hdr_histogram_new(vmin, vmax, sigfigs);
}
} else {
/* No records, no need to reset. */
}
#endif
mtx_unlock(&src->ra_lock);
rd_avg_calc(dst, now);
}
/**
* Initialize an averager
*/
static RD_UNUSED void rd_avg_init(rd_avg_t *ra,
int type,
int64_t exp_min,
int64_t exp_max,
int sigfigs,
int enable) {
memset(ra, 0, sizeof(*ra));
mtx_init(&ra->ra_lock, 0);
ra->ra_enabled = enable;
if (!enable)
return;
ra->ra_type = type;
ra->ra_v.start = rd_clock();
#if WITH_HDRHISTOGRAM
/* Start off the histogram with expected min,max span,
* we'll adapt the size on each rollover. */
ra->ra_hdr = rd_hdr_histogram_new(exp_min, exp_max, sigfigs);
#endif
}
/**
* Destroy averager
*/
static RD_UNUSED void rd_avg_destroy(rd_avg_t *ra) {
#if WITH_HDRHISTOGRAM
if (ra->ra_hdr)
rd_hdr_histogram_destroy(ra->ra_hdr);
#endif
mtx_destroy(&ra->ra_lock);
}
#endif /* _RDAVG_H_ */
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