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/*
* Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "coverage.h"
#include <inttypes.h>
#include <stdlib.h>
#include "dynamic-string.h"
#include "hash.h"
#include "svec.h"
#include "timeval.h"
#include "unixctl.h"
#include "util.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(coverage);
/* The coverage counters. */
static struct coverage_counter **coverage_counters = NULL;
static size_t n_coverage_counters = 0;
static size_t allocated_coverage_counters = 0;
static struct ovs_mutex coverage_mutex = OVS_MUTEX_INITIALIZER;
DEFINE_STATIC_PER_THREAD_DATA(long long int, coverage_clear_time, LLONG_MIN);
static long long int coverage_run_time = LLONG_MIN;
/* Index counter used to compute the moving average array's index. */
static unsigned int idx_count = 0;
static void coverage_read(struct svec *);
static unsigned int coverage_array_sum(const unsigned int *arr,
const unsigned int len);
/* Registers a coverage counter with the coverage core */
void
coverage_counter_register(struct coverage_counter* counter)
{
if (n_coverage_counters >= allocated_coverage_counters) {
coverage_counters = x2nrealloc(coverage_counters,
&allocated_coverage_counters,
sizeof(struct coverage_counter*));
}
coverage_counters[n_coverage_counters++] = counter;
}
static void
coverage_unixctl_show(struct unixctl_conn *conn, int argc OVS_UNUSED,
const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
{
struct svec lines;
char *reply;
svec_init(&lines);
coverage_read(&lines);
reply = svec_join(&lines, "\n", "\n");
unixctl_command_reply(conn, reply);
free(reply);
svec_destroy(&lines);
}
void
coverage_init(void)
{
unixctl_command_register("coverage/show", "", 0, 0,
coverage_unixctl_show, NULL);
}
/* Sorts coverage counters in descending order by total, within equal
* totals alphabetically by name. */
static int
compare_coverage_counters(const void *a_, const void *b_)
{
const struct coverage_counter *const *ap = a_;
const struct coverage_counter *const *bp = b_;
const struct coverage_counter *a = *ap;
const struct coverage_counter *b = *bp;
if (a->total != b->total) {
return a->total < b->total ? 1 : -1;
} else {
return strcmp(a->name, b->name);
}
}
static uint32_t
coverage_hash(void)
{
struct coverage_counter **c;
uint32_t hash = 0;
int n_groups, i;
/* Sort coverage counters into groups with equal totals. */
c = xmalloc(n_coverage_counters * sizeof *c);
ovs_mutex_lock(&coverage_mutex);
for (i = 0; i < n_coverage_counters; i++) {
c[i] = coverage_counters[i];
}
ovs_mutex_unlock(&coverage_mutex);
qsort(c, n_coverage_counters, sizeof *c, compare_coverage_counters);
/* Hash the names in each group along with the rank. */
n_groups = 0;
for (i = 0; i < n_coverage_counters; ) {
int j;
if (!c[i]->total) {
break;
}
n_groups++;
hash = hash_int(i, hash);
for (j = i; j < n_coverage_counters; j++) {
if (c[j]->total != c[i]->total) {
break;
}
hash = hash_string(c[j]->name, hash);
}
i = j;
}
free(c);
return hash_int(n_groups, hash);
}
static bool
coverage_hit(uint32_t hash)
{
enum { HIT_BITS = 1024, BITS_PER_WORD = 32 };
static uint32_t hit[HIT_BITS / BITS_PER_WORD];
BUILD_ASSERT_DECL(IS_POW2(HIT_BITS));
static long long int next_clear = LLONG_MIN;
unsigned int bit_index = hash & (HIT_BITS - 1);
unsigned int word_index = bit_index / BITS_PER_WORD;
unsigned int word_mask = 1u << (bit_index % BITS_PER_WORD);
/* Expire coverage hash suppression once a day. */
if (time_msec() >= next_clear) {
memset(hit, 0, sizeof hit);
next_clear = time_msec() + 60 * 60 * 24 * 1000LL;
}
if (hit[word_index] & word_mask) {
return true;
} else {
hit[word_index] |= word_mask;
return false;
}
}
/* Logs the coverage counters, unless a similar set of events has already been
* logged.
*
* This function logs at log level VLL_INFO. Use care before adjusting this
* level, because depending on its configuration, syslogd can write changes
* synchronously, which can cause the coverage messages to take several seconds
* to write. */
void
coverage_log(void)
{
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 3);
if (!VLOG_DROP_INFO(&rl)) {
uint32_t hash = coverage_hash();
if (coverage_hit(hash)) {
VLOG_INFO("Skipping details of duplicate event coverage for "
"hash=%08"PRIx32, hash);
} else {
struct svec lines;
const char *line;
size_t i;
svec_init(&lines);
coverage_read(&lines);
SVEC_FOR_EACH (i, line, &lines) {
VLOG_INFO("%s", line);
}
svec_destroy(&lines);
}
}
}
/* Adds coverage counter information to 'lines'. */
static void
coverage_read(struct svec *lines)
{
struct coverage_counter **c = coverage_counters;
unsigned long long int *totals;
size_t n_never_hit;
uint32_t hash;
size_t i;
hash = coverage_hash();
n_never_hit = 0;
svec_add_nocopy(lines,
xasprintf("Event coverage, avg rate over last: %d "
"seconds, last minute, last hour, "
"hash=%08"PRIx32":",
COVERAGE_RUN_INTERVAL/1000, hash));
totals = xmalloc(n_coverage_counters * sizeof *totals);
ovs_mutex_lock(&coverage_mutex);
for (i = 0; i < n_coverage_counters; i++) {
totals[i] = c[i]->total;
}
ovs_mutex_unlock(&coverage_mutex);
for (i = 0; i < n_coverage_counters; i++) {
if (totals[i]) {
/* Shows the averaged per-second rates for the last
* COVERAGE_RUN_INTERVAL interval, the last minute and
* the last hour. */
svec_add_nocopy(lines,
xasprintf("%-24s %5.1f/sec %9.3f/sec "
"%13.4f/sec total: %llu",
c[i]->name,
(c[i]->min[(idx_count - 1) % MIN_AVG_LEN]
* 1000.0 / COVERAGE_RUN_INTERVAL),
coverage_array_sum(c[i]->min, MIN_AVG_LEN) / 60.0,
coverage_array_sum(c[i]->hr, HR_AVG_LEN) / 3600.0,
totals[i]));
} else {
n_never_hit++;
}
}
svec_add_nocopy(lines, xasprintf("%"PRIuSIZE" events never hit", n_never_hit));
free(totals);
}
/* Runs approximately every COVERAGE_CLEAR_INTERVAL amount of time to
* synchronize per-thread counters with global counters. Every thread maintains
* a separate timer to ensure all counters are periodically aggregated. */
void
coverage_clear(void)
{
long long int now, *thread_time;
now = time_msec();
thread_time = coverage_clear_time_get();
/* Initialize the coverage_clear_time. */
if (*thread_time == LLONG_MIN) {
*thread_time = now + COVERAGE_CLEAR_INTERVAL;
}
if (now >= *thread_time) {
size_t i;
ovs_mutex_lock(&coverage_mutex);
for (i = 0; i < n_coverage_counters; i++) {
struct coverage_counter *c = coverage_counters[i];
c->total += c->count();
}
ovs_mutex_unlock(&coverage_mutex);
*thread_time = now + COVERAGE_CLEAR_INTERVAL;
}
}
/* Runs approximately every COVERAGE_RUN_INTERVAL amount of time to update the
* coverage counters' 'min' and 'hr' array. 'min' array is for cumulating
* per second counts into per minute count. 'hr' array is for cumulating per
* minute counts into per hour count. Every thread may call this function. */
void
coverage_run(void)
{
/* Defines the moving average array index variables. */
static unsigned int min_idx, hr_idx;
struct coverage_counter **c = coverage_counters;
long long int now;
ovs_mutex_lock(&coverage_mutex);
now = time_msec();
/* Initialize the coverage_run_time. */
if (coverage_run_time == LLONG_MIN) {
coverage_run_time = now + COVERAGE_RUN_INTERVAL;
}
if (now >= coverage_run_time) {
size_t i, j;
/* Computes the number of COVERAGE_RUN_INTERVAL slots, since
* it is possible that the actual run interval is multiple of
* COVERAGE_RUN_INTERVAL. */
int slots = (now - coverage_run_time) / COVERAGE_RUN_INTERVAL + 1;
for (i = 0; i < n_coverage_counters; i++) {
unsigned int count, portion;
unsigned int m_idx = min_idx;
unsigned int h_idx = hr_idx;
unsigned int idx = idx_count;
/* Computes the differences between the current total and the one
* recorded in last invocation of coverage_run(). */
count = c[i]->total - c[i]->last_total;
c[i]->last_total = c[i]->total;
/* The count over the time interval is evenly distributed
* among slots by calculating the portion. */
portion = count / slots;
for (j = 0; j < slots; j++) {
/* Updates the index variables. */
/* The m_idx is increased from 0 to MIN_AVG_LEN - 1. Every
* time the m_idx finishes a cycle (a cycle is one minute),
* the h_idx is incremented by 1. */
m_idx = idx % MIN_AVG_LEN;
h_idx = idx / MIN_AVG_LEN;
c[i]->min[m_idx] = portion + (j == (slots - 1)
? count % slots : 0);
c[i]->hr[h_idx] = m_idx == 0
? c[i]->min[m_idx]
: (c[i]->hr[h_idx] + c[i]->min[m_idx]);
/* This is to guarantee that h_idx ranges from 0 to 59. */
idx = (idx + 1) % (MIN_AVG_LEN * HR_AVG_LEN);
}
}
/* Updates the global index variables. */
idx_count = (idx_count + slots) % (MIN_AVG_LEN * HR_AVG_LEN);
min_idx = idx_count % MIN_AVG_LEN;
hr_idx = idx_count / MIN_AVG_LEN;
/* Updates the run time. */
coverage_run_time = now + COVERAGE_RUN_INTERVAL;
}
ovs_mutex_unlock(&coverage_mutex);
}
static unsigned int
coverage_array_sum(const unsigned int *arr, const unsigned int len)
{
unsigned int sum = 0;
size_t i;
ovs_mutex_lock(&coverage_mutex);
for (i = 0; i < len; i++) {
sum += arr[i];
}
ovs_mutex_unlock(&coverage_mutex);
return sum;
}
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