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scheduler: Remove hashtab usage.
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This is a first stab at tweaking the performance profile of the scheduler. Removing
the hashtab usage removes an extra memory allocation when scheduling something and
makes it so rescheduling does not incur any memory allocation at all.

Review: https://reviewboard.asterisk.org/r/3199/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@407958 65c4cc65-6c06-0410-ace0-fbb531ad65f3
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@jcolp
jcolp committed Feb 11, 2014
1 parent 0ebbeac commit 6bdf2c4
Showing 1 changed file with 41 additions and 62 deletions.
103 changes: 41 additions & 62 deletions main/sched.c
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Original file line number Diff line number Diff line change
Expand Up @@ -47,9 +47,6 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/channel.h"
#include "asterisk/lock.h"
#include "asterisk/utils.h"
#include "asterisk/linkedlists.h"
#include "asterisk/dlinkedlists.h"
#include "asterisk/hashtab.h"
#include "asterisk/heap.h"
#include "asterisk/threadstorage.h"

Expand Down Expand Up @@ -85,9 +82,7 @@ struct sched_thread {
struct ast_sched_context {
ast_mutex_t lock;
unsigned int eventcnt; /*!< Number of events processed */
unsigned int schedcnt; /*!< Number of outstanding schedule events */
unsigned int highwater; /*!< highest count so far */
struct ast_hashtab *schedq_ht; /*!< hash table for fast searching */
struct ast_heap *sched_heap;
struct sched_thread *sched_thread;

Expand Down Expand Up @@ -188,20 +183,6 @@ int ast_sched_start_thread(struct ast_sched_context *con)
return 0;
}

static int sched_cmp(const void *a, const void *b)
{
const struct sched *as = a;
const struct sched *bs = b;
return as->id != bs->id; /* return 0 on a match like strcmp would */
}

static unsigned int sched_hash(const void *obj)
{
const struct sched *s = obj;
unsigned int h = s->id;
return h;
}

static int sched_time_cmp(void *a, void *b)
{
return ast_tvcmp(((struct sched *) b)->when, ((struct sched *) a)->when);
Expand All @@ -218,8 +199,6 @@ struct ast_sched_context *ast_sched_context_create(void)
ast_mutex_init(&tmp->lock);
tmp->eventcnt = 1;

tmp->schedq_ht = ast_hashtab_create(23, sched_cmp, ast_hashtab_resize_java, ast_hashtab_newsize_java, sched_hash, 1);

if (!(tmp->sched_heap = ast_heap_create(8, sched_time_cmp,
offsetof(struct sched, __heap_index)))) {
ast_sched_context_destroy(tmp);
Expand Down Expand Up @@ -252,9 +231,6 @@ void ast_sched_context_destroy(struct ast_sched_context *con)
con->sched_heap = NULL;
}

ast_hashtab_destroy(con->schedq_ht, NULL);
con->schedq_ht = NULL;

ast_mutex_unlock(&con->lock);
ast_mutex_destroy(&con->lock);

Expand Down Expand Up @@ -330,14 +306,8 @@ static void schedule(struct ast_sched_context *con, struct sched *s)
{
ast_heap_push(con->sched_heap, s);

if (!ast_hashtab_insert_safe(con->schedq_ht, s)) {
ast_log(LOG_WARNING,"Schedule Queue entry %d is already in table!\n", s->id);
}

con->schedcnt++;

if (con->schedcnt > con->highwater) {
con->highwater = con->schedcnt;
if (ast_heap_size(con->sched_heap) > con->highwater) {
con->highwater = ast_heap_size(con->sched_heap);
}
}

Expand Down Expand Up @@ -419,16 +389,40 @@ int ast_sched_add(struct ast_sched_context *con, int when, ast_sched_cb callback
return ast_sched_add_variable(con, when, callback, data, 0);
}

const void *ast_sched_find_data(struct ast_sched_context *con, int id)
static struct sched *sched_find(struct ast_sched_context *con, int id)
{
struct sched tmp,*res;
tmp.id = id;
res = ast_hashtab_lookup(con->schedq_ht, &tmp);
if (res)
return res->data;
int x;
size_t heap_size;

heap_size = ast_heap_size(con->sched_heap);
for (x = 1; x <= heap_size; x++) {
struct sched *cur = ast_heap_peek(con->sched_heap, x);

if (cur->id == id) {
return cur;
}
}

return NULL;
}

const void *ast_sched_find_data(struct ast_sched_context *con, int id)
{
struct sched *s;
const void *data = NULL;

ast_mutex_lock(&con->lock);

s = sched_find(con, id);
if (s) {
data = s->data;
}

ast_mutex_unlock(&con->lock);

return data;
}

/*! \brief
* Delete the schedule entry with number
* "id". It's nearly impossible that there
Expand All @@ -441,9 +435,7 @@ int ast_sched_del(struct ast_sched_context *con, int id)
int _ast_sched_del(struct ast_sched_context *con, int id, const char *file, int line, const char *function)
#endif
{
struct sched *s, tmp = {
.id = id,
};
struct sched *s = NULL;
int *last_id = ast_threadstorage_get(&last_del_id, sizeof(int));

DEBUG(ast_debug(1, "ast_sched_del(%d)\n", id));
Expand All @@ -453,18 +445,13 @@ int _ast_sched_del(struct ast_sched_context *con, int id, const char *file, int
}

ast_mutex_lock(&con->lock);
s = ast_hashtab_lookup(con->schedq_ht, &tmp);

s = sched_find(con, id);
if (s) {
if (!ast_heap_remove(con->sched_heap, s)) {
ast_log(LOG_WARNING,"sched entry %d not in the sched heap?\n", s->id);
}

if (!ast_hashtab_remove_this_object(con->schedq_ht, s)) {
ast_log(LOG_WARNING,"Found sched entry %d, then couldn't remove it?\n", s->id);
}

con->schedcnt--;

sched_release(con, s);
}

Expand Down Expand Up @@ -506,7 +493,7 @@ void ast_sched_report(struct ast_sched_context *con, struct ast_str **buf, struc
size_t heap_size;

memset(countlist, 0, sizeof(countlist));
ast_str_set(buf, 0, " Highwater = %d\n schedcnt = %d\n", con->highwater, con->schedcnt);
ast_str_set(buf, 0, " Highwater = %d\n schedcnt = %zd\n", con->highwater, ast_heap_size(con->sched_heap));

ast_mutex_lock(&con->lock);

Expand Down Expand Up @@ -543,9 +530,9 @@ void ast_sched_dump(struct ast_sched_context *con)
int x;
size_t heap_size;
#ifdef SCHED_MAX_CACHE
ast_debug(1, "Asterisk Schedule Dump (%d in Q, %d Total, %d Cache, %d high-water)\n", con->schedcnt, con->eventcnt - 1, con->schedccnt, con->highwater);
ast_debug(1, "Asterisk Schedule Dump (%zd in Q, %d Total, %d Cache, %d high-water)\n", ast_heap_size(con->sched_heap), con->eventcnt - 1, con->schedccnt, con->highwater);
#else
ast_debug(1, "Asterisk Schedule Dump (%d in Q, %d Total, %d high-water)\n", con->schedcnt, con->eventcnt - 1, con->highwater);
ast_debug(1, "Asterisk Schedule Dump (%zd in Q, %d Total, %d high-water)\n", ast_heap_size(con->sched_heap), con->eventcnt - 1, con->highwater);
#endif

ast_debug(1, "=============================================================\n");
Expand Down Expand Up @@ -595,12 +582,6 @@ int ast_sched_runq(struct ast_sched_context *con)

current = ast_heap_pop(con->sched_heap);

if (!ast_hashtab_remove_this_object(con->schedq_ht, current)) {
ast_log(LOG_ERROR,"Sched entry %d was in the schedq list but not in the hashtab???\n", current->id);
}

con->schedcnt--;

/*
* At this point, the schedule queue is still intact. We
* have removed the first event and the rest is still there,
Expand Down Expand Up @@ -637,20 +618,18 @@ int ast_sched_runq(struct ast_sched_context *con)

long ast_sched_when(struct ast_sched_context *con,int id)
{
struct sched *s, tmp;
struct sched *s;
long secs = -1;
DEBUG(ast_debug(1, "ast_sched_when()\n"));

ast_mutex_lock(&con->lock);

/* these next 2 lines replace a lookup loop */
tmp.id = id;
s = ast_hashtab_lookup(con->schedq_ht, &tmp);

s = sched_find(con, id);
if (s) {
struct timeval now = ast_tvnow();
secs = s->when.tv_sec - now.tv_sec;
}

ast_mutex_unlock(&con->lock);

return secs;
Expand Down

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