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/* Copyright (C) 2009 Intel Corporation
Author: Andi Kleen
Leaky bucket algorithm. This is used for all error triggers.
mcelog is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; version
2.
mcelog is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should find a copy of v2 of the GNU General Public License somewhere
on your Linux system; if not, write to the Free Software Foundation,
Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#define _GNU_SOURCE 1
#include <stdio.h>
#include <ctype.h>
#include "memutil.h"
#include "leaky-bucket.h"
time_t __attribute__((weak)) bucket_time(void)
{
return time(NULL);
}
void bucket_age(const struct bucket_conf *c, struct leaky_bucket *b,
time_t now)
{
long diff;
diff = now - b->tstamp;
if (diff >= c->agetime) {
unsigned age = (diff / (double)c->agetime) * c->capacity;
b->tstamp = now;
if (age > b->count)
b->count = 0;
else
b->count -= age;
b->excess = 0;
}
}
/* Account increase in leaky bucket. Return 1 if bucket overflowed. */
int __bucket_account(const struct bucket_conf *c, struct leaky_bucket *b,
unsigned inc, time_t t)
{
if (c->capacity == 0)
return 0;
bucket_age(c, b, t);
b->count += inc;
if (b->count >= c->capacity) {
b->excess += b->count;
/* should disable overflow completely in the same time unit */
b->count = 0;
return 1;
}
return 0;
}
int bucket_account(const struct bucket_conf *c, struct leaky_bucket *b,
unsigned inc)
{
return __bucket_account(c, b, inc, bucket_time());
}
static int timeconv(char unit, int *out)
{
unsigned corr = 1;
switch (unit) {
case 'd': corr *= 24; /* FALL THROUGH */
case 'h': corr *= 60; /* FALL THROUGH */
case 'm': corr *= 60; /* FALL THROUGH */
case 0: break;
default:
*out = 1;
return -1;
}
*out = corr;
return 0;
}
/* Format leaky bucket as a string. Caller must free string */
char *bucket_output(const struct bucket_conf *c, struct leaky_bucket *b)
{
char *buf;
if (c->capacity == 0) {
xasprintf(&buf, "not enabled");
} else {
int unit = 0;
//bucket_age(c, b, bucket_time());
timeconv(c->tunit, &unit);
xasprintf(&buf, "%u in %u%c", b->count + b->excess,
c->agetime/unit, c->tunit);
}
return buf;
}
/* Parse user specified capacity / rate string */
/* capacity / time
time: number [hmds]
capacity: number [kmg] */
static int parse_rate(const char *rate, struct bucket_conf *c)
{
char cunit[2], tunit[2];
unsigned cap, t;
int n;
int unit;
cunit[0] = 0;
tunit[0] = 0;
n = sscanf(rate, "%u %1s / %u %1s", &cap, cunit, &t, tunit);
if (n != 4) {
cunit[0] = 0;
tunit[0] = 0;
if (n <= 2) {
n = sscanf(rate, "%u / %u %1s", &cap, &t, tunit);
if (n < 2)
return -1;
} else
return -1;
}
if (t == 0 || cap == 0)
return -1;
switch (tolower(cunit[0])) {
case 'g': cap *= 1000; /* FALL THROUGH */
case 'm': cap *= 1000; /* FALL THROUGH */
case 'k': cap *= 1000; /* FALL THROUGH */
case 0: break;
default: return -1;
}
c->tunit = tolower(tunit[0]);
if (timeconv(c->tunit, &unit) < 0)
return -1;
c->agetime = unit * t;
c->capacity = cap;
return 0;
}
/* Initialize leaky bucket conf for given user rate/capacity string. <0 on error */
int bucket_conf_init(struct bucket_conf *c, const char *rate)
{
if (parse_rate(rate, c) < 0)
return -1;
c->trigger = NULL;
return 0;
}
/* Initialize leaky bucket instance. */
void bucket_init(struct leaky_bucket *b)
{
b->count = 0;
b->excess = 0;
b->tstamp = bucket_time();
}
#ifdef TEST_LEAKY_BUCKET
/* Stolen from the cpp documentation */
#define xstr(_s) str(_s)
#define str(_s) #_s
#define THRESHOLD_EVENTS_PER_PERIOD 100
#define EVENTS_PER_LOGGED_EVENT 10
#define SECONDS_PER_EVENT 86
/* Needs to be SECONDS_PER_EVENT * EVENTS_PER_LOGGED_EVENT * THRESHOLD_EVENTS_PER_PERIOD */
#define THRESHOLD_PERIOD 86000
#if THRESHOLD_PERIOD != (SECONDS_PER_EVENT * EVENTS_PER_LOGGED_EVENT * THRESHOLD_EVENTS_PER_PERIOD)
# error THRESHOLD_PERIOD is Wrong!
#endif
#define RATE_STRING xstr(THRESHOLD_EVENTS_PER_PERIOD) " / " xstr(THRESHOLD_PERIOD)
#define EVENTS_PER_PERIOD_IN_TEST (THRESHOLD_EVENTS_PER_PERIOD * EVENTS_PER_LOGGED_EVENT)
#define PERIODS_TO_TEST 3
#define TOTAL_SECONDS_FOR_TEST (PERIODS_TO_TEST * THRESHOLD_PERIOD)
#define TOTAL_EVENTS (PERIODS_TO_TEST * EVENTS_PER_PERIOD_IN_TEST)
int main(int argc, char **argv)
{
struct bucket_conf c;
struct leaky_bucket b;
time_t start_time;
time_t event_time;
int ret;
int i;
#ifdef TEST_LEAKY_BUCKET_DEBUG
printf("Testing with a rate of " RATE_STRING "\n");
#endif
ret = bucket_conf_init(&c, RATE_STRING);
if (ret)
return ret;
bucket_init(&b);
start_time = b.tstamp;
for (i = 1; i <= TOTAL_EVENTS; i++) {
event_time = start_time + i * SECONDS_PER_EVENT;
ret = __bucket_account(&c, &b, 1, event_time);
#ifdef TEST_LEAKY_BUCKET_DEBUG
if (ret)
printf("Logging entry %d at %ld %ld\n", i, event_time - start_time, b.tstamp);
#else
if (i < THRESHOLD_EVENTS_PER_PERIOD) {
if (!ret){
fprintf(stderr, "Did not log initial events - FAIL.\n");
return -1;
}
} else {
if (!(i % EVENTS_PER_LOGGED_EVENT) && !ret) {
fprintf(stderr, "Did not log initial events - FAIL.\n");
return -1;
}
}
#endif
}
return 0;
}
#endif
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