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All lbmethods are now ind submodules...
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git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@722952 13f79535-47bb-0310-9956-ffa450edef68
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Jim Jagielski committed Dec 3, 2008
1 parent c8536a7 commit 6d28430
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Showing 2 changed files with 1 addition and 308 deletions.
2 changes: 1 addition & 1 deletion modules/proxy/Makefile.in
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
# a modules Makefile has no explicit targets -- they will be defined by
# whatever modules are enabled. just grab special.mk to deal with this.
#SUBDIRS = balancers
SUBDIRS = balancers
include $(top_srcdir)/build/special.mk
307 changes: 0 additions & 307 deletions modules/proxy/mod_proxy_balancer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -941,310 +941,6 @@ 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 *mycandidate = NULL;
int cur_lbset = 0;
int max_lbset = 0;
int checking_standby;
int checked_standby;

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 */
do {
checking_standby = checked_standby = 0;
while (!mycandidate && !checked_standby) {
worker = (proxy_worker *)balancer->workers->elts;
for (i = 0; i < balancer->workers->nelts; i++, worker++) {
if (!checking_standby) { /* first time through */
if (worker->s->lbset > max_lbset)
max_lbset = worker->s->lbset;
}
if (worker->s->lbset > cur_lbset)
continue;
if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
continue;
/* 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;
}
}
checked_standby = checking_standby++;
}
cur_lbset++;
} while (cur_lbset <= max_lbset && !mycandidate);

if (mycandidate) {
mycandidate->s->lbstatus -= total_factor;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: byrequests selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d",
mycandidate->name, mycandidate->s->busy, mycandidate->s->lbstatus);

}

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 *mycandidate = NULL;
int cur_lbset = 0;
int max_lbset = 0;
int checking_standby;
int checked_standby;

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 */
do {
checking_standby = checked_standby = 0;
while (!mycandidate && !checked_standby) {
worker = (proxy_worker *)balancer->workers->elts;
for (i = 0; i < balancer->workers->nelts; i++, worker++) {
if (!checking_standby) { /* first time through */
if (worker->s->lbset > max_lbset)
max_lbset = worker->s->lbset;
}
if (worker->s->lbset > cur_lbset)
continue;
if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
continue;
/* 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;
}
}
}
checked_standby = checking_standby++;
}
cur_lbset++;
} while (cur_lbset <= max_lbset && !mycandidate);

if (mycandidate) {
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: bytraffic selected worker \"%s\" : busy %" APR_SIZE_T_FMT,
mycandidate->name, mycandidate->s->busy);

}

return mycandidate;
}

static proxy_worker *find_best_bybusyness(proxy_balancer *balancer,
request_rec *r)
{

int i;
proxy_worker *worker;
proxy_worker *mycandidate = NULL;
int cur_lbset = 0;
int max_lbset = 0;
int checking_standby;
int checked_standby;

int total_factor = 0;

ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: Entering bybusyness for BALANCER (%s)",
balancer->name);

/* First try to see if we have available candidate */
do {

checking_standby = checked_standby = 0;
while (!mycandidate && !checked_standby) {

worker = (proxy_worker *)balancer->workers->elts;
for (i = 0; i < balancer->workers->nelts; i++, worker++) {
if (!checking_standby) { /* first time through */
if (worker->s->lbset > max_lbset)
max_lbset = worker->s->lbset;
}

if (worker->s->lbset > cur_lbset)
continue;

if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
continue;

/* 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->busy < mycandidate->s->busy
|| (worker->s->busy == mycandidate->s->busy && worker->s->lbstatus > mycandidate->s->lbstatus))
mycandidate = worker;

}

}

checked_standby = checking_standby++;

}

cur_lbset++;

} while (cur_lbset <= max_lbset && !mycandidate);

if (mycandidate) {
mycandidate->s->lbstatus -= total_factor;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: bybusyness selected worker \"%s\" : busy %" APR_SIZE_T_FMT " : lbstatus %d",
mycandidate->name, mycandidate->s->busy, mycandidate->s->lbstatus);

}

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 const proxy_balancer_method bybusyness =
{
"bybusyness",
&find_best_bybusyness,
NULL
};


static void ap_proxy_balancer_register_hook(apr_pool_t *p)
{
/* Only the mpm_winnt has child init hook handler.
Expand All @@ -1259,9 +955,6 @@ 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);
ap_register_provider(p, PROXY_LBMETHOD, "bybusyness", "0", &bybusyness);
}

module AP_MODULE_DECLARE_DATA proxy_balancer_module = {
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