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Proxy balancer lbmethods are now registered as providers and not

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via hooks. Move various find() functions back to mod_proxy_balancer
where they belong :)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@279752 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Jim Jagielski
2005-09-09 12:28:02 +00:00
parent cb68a807de
commit 22c5cb4728
4 changed files with 196 additions and 220 deletions
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200
modules/proxy/mod_proxy_balancer.c
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@@ -516,15 +516,9 @@ static int balancer_handler(request_rec *r)
bsel->max_attempts_set = 1;
}
if ((val = apr_table_get(params, "lm"))) {
struct proxy_balancer_method *ent =
(struct proxy_balancer_method *) conf->lbmethods->elts;
int i;
for (i = 0; i < conf->lbmethods->nelts; i++) {
if (!strcasecmp(val, ent->name)) {
bsel->lbmethod = ent;
break;
}
ent++;
proxy_balancer_method *provider;
if (provider = ap_lookup_provider(PROXY_LBMETHOD, val, "0")) {
bsel->lbmethod = provider;
}
}
}
@@ -695,14 +689,16 @@ static int balancer_handler(request_rec *r)
bsel->max_attempts);
ap_rputs("<tr><td>LB Method:</td><td><select name=\"lm\">", r);
{
struct proxy_balancer_method *ent =
(struct proxy_balancer_method *) conf->lbmethods->elts;
apr_array_header_t *methods;
ap_list_provider_names_t *method;
int i;
for (i = 0; i < conf->lbmethods->nelts; i++) {
ap_rprintf(r, "<option value=\"%s\" %s>%s</option>", ent->name,
(!strcasecmp(bsel->lbmethod->name, ent->name)) ? "selected" : "",
ent->name);
ent++;
methods = ap_list_provider_names(r->pool, PROXY_LBMETHOD, "0");
method = (ap_list_provider_names_t *)methods->elts;
for (i = 0; i < methods->nelts; i++) {
ap_rprintf(r, "<option value=\"%s\" %s>%s</option>", method->provider_name,
(!strcasecmp(bsel->lbmethod->name, method->provider_name)) ? "selected" : "",
method->provider_name);
method++;
}
}
ap_rputs("</select></td></tr>\n", r);
@@ -738,6 +734,176 @@ static void child_init(apr_pool_t *p, server_rec *s)
}
/*
* The idea behind the find_best_byrequests scheduler is the following:
*
* lbfactor is "how much we expect this worker to work", or "the worker's
* normalized work quota".
*
* lbstatus is "how urgent this worker has to work to fulfill its quota
* of work".
*
* We distribute each worker's work quota to the worker, and then look
* which of them needs to work most urgently (biggest lbstatus). This
* worker is then selected for work, and its lbstatus reduced by the
* total work quota we distributed to all workers. Thus the sum of all
* lbstatus does not change.(*)
*
* If some workers are disabled, the others will
* still be scheduled correctly.
*
* If a balancer is configured as follows:
*
* worker a b c d
* lbfactor 25 25 25 25
*
* And b gets disabled, the following schedule is produced:
*
* a c d a c d a c d ...
*
* Note that the above lbfactor setting is the *exact* same as:
*
* worker a b c d
* lbfactor 1 1 1 1
*
* Asymmetric configurations work as one would expect. For
* example:
*
* worker a b c d
* lbfactor 1 1 1 2
*
* would have a, b and c all handling about the same
* amount of load with d handling twice what a or b
* or c handles individually. So we could see:
*
* b a d c d a c d b d ...
*
*/
static proxy_worker *find_best_byrequests(proxy_balancer *balancer,
request_rec *r)
{
int i;
int total_factor = 0;
proxy_worker *worker = (proxy_worker *)balancer->workers->elts;
proxy_worker *mycandidate = NULL;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: Entering byrequests for BALANCER (%s)",
balancer->name);
/* First try to see if we have available candidate */
for (i = 0; i < balancer->workers->nelts; i++) {
/* If the worker is in error state run
* retry on that worker. It will be marked as
* operational if the retry timeout is elapsed.
* The worker might still be unusable, but we try
* anyway.
*/
if (!PROXY_WORKER_IS_USABLE(worker))
ap_proxy_retry_worker("BALANCER", worker, r->server);
/* Take into calculation only the workers that are
* not in error state or not disabled.
*/
if (PROXY_WORKER_IS_USABLE(worker)) {
worker->s->lbstatus += worker->s->lbfactor;
total_factor += worker->s->lbfactor;
if (!mycandidate || worker->s->lbstatus > mycandidate->s->lbstatus)
mycandidate = worker;
}
worker++;
}
if (mycandidate) {
mycandidate->s->lbstatus -= total_factor;
mycandidate->s->elected++;
}
return mycandidate;
}
/*
* The idea behind the find_best_bytraffic scheduler is the following:
*
* We know the amount of traffic (bytes in and out) handled by each
* worker. We normalize that traffic by each workers' weight. So assuming
* a setup as below:
*
* worker a b c
* lbfactor 1 1 3
*
* the scheduler will allow worker c to handle 3 times the
* traffic of a and b. If each request/response results in the
* same amount of traffic, then c would be accessed 3 times as
* often as a or b. If, for example, a handled a request that
* resulted in a large i/o bytecount, then b and c would be
* chosen more often, to even things out.
*/
static proxy_worker *find_best_bytraffic(proxy_balancer *balancer,
request_rec *r)
{
int i;
apr_off_t mytraffic = 0;
apr_off_t curmin = 0;
proxy_worker *worker = (proxy_worker *)balancer->workers->elts;
proxy_worker *mycandidate = NULL;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: Entering bytraffic for BALANCER (%s)",
balancer->name);
/* First try to see if we have available candidate */
for (i = 0; i < balancer->workers->nelts; i++) {
/* If the worker is in error state run
* retry on that worker. It will be marked as
* operational if the retry timeout is elapsed.
* The worker might still be unusable, but we try
* anyway.
*/
if (!PROXY_WORKER_IS_USABLE(worker))
ap_proxy_retry_worker("BALANCER", worker, r->server);
/* Take into calculation only the workers that are
* not in error state or not disabled.
*/
if (PROXY_WORKER_IS_USABLE(worker)) {
mytraffic = (worker->s->transferred/worker->s->lbfactor) +
(worker->s->read/worker->s->lbfactor);
if (!mycandidate || mytraffic < curmin) {
mycandidate = worker;
curmin = mytraffic;
}
}
worker++;
}
if (mycandidate) {
mycandidate->s->elected++;
}
return mycandidate;
}
/*
* How to add additional lbmethods:
* 1. Create func which determines "best" candidate worker
* (eg: find_best_bytraffic, above)
* 2. Register it as a provider.
*/
static const proxy_balancer_method byrequests =
{
"byrequests",
&find_best_byrequests,
NULL
};
static const proxy_balancer_method bytraffic =
{
"bytraffic",
&find_best_bytraffic,
NULL
};
static void ap_proxy_balancer_register_hook(apr_pool_t *p)
{
/* Only the mpm_winnt has child init hook handler.
@@ -751,6 +917,8 @@ static void ap_proxy_balancer_register_hook(apr_pool_t *p)
proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
ap_register_provider(p, PROXY_LBMETHOD, "bytraffic", "0", &bytraffic);
ap_register_provider(p, PROXY_LBMETHOD, "byrequests", "0", &byrequests);
}
module AP_MODULE_DECLARE_DATA proxy_balancer_module = {