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OPTIM/MINOR: config: Optimize fullconn automatic computation loading configuration

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The previous version used an O(number of proxies)^2 algo to get the sum of
the number of maxconns of frontends which reference a backend at least once.

This new version adds the frontend's maxconn number to the backend's
struct proxy member 'tot_fe_maxconn' when the backend name is resolved
for switching rules or default_backend statment.  At the end, the final
backend's fullconn is computed looping only one time for all on proxies O(n).

The load of a configuration using a large amount of backends (10 thousands)
without configured fullconn was reduced from several minutes to few seconds.
This commit is contained in:
Emeric Brun 2017-01-12 11:21:28 +01:00 committed by Willy Tarreau
parent 3eb5b3fdd3
commit 3f78357066
2 changed files with 29 additions and 39 deletions
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1
include/types/proxy.h
View File

@ -326,6 +326,7 @@ struct proxy {
struct freq_ctr be_sess_per_sec; /* sessions per second on the backend */
unsigned int fe_sps_lim; /* limit on new sessions per second on the frontend */
unsigned int fullconn; /* #conns on backend above which servers are used at full load */
unsigned int tot_fe_maxconn; /* #maxconn of frontends linked to that backend, it is used to compute fullconn */
struct in_addr except_net, except_mask; /* don't x-forward-for for this address. FIXME: should support IPv6 */
struct in_addr except_to; /* don't x-original-to for this address. */
struct in_addr except_mask_to; /* the netmask for except_to. */

67
src/cfgparse.c
View File

@ -7542,7 +7542,8 @@ int check_config_validity()
} else {
free(curproxy->defbe.name);
curproxy->defbe.be = target;
/* Update tot_fe_maxconn for a further fullconn's computation */
target->tot_fe_maxconn += curproxy->maxconn;
/* Emit a warning if this proxy also has some servers */
if (curproxy->srv) {
Warning("In proxy '%s', the 'default_backend' rule always has precedence over the servers, which will never be used.\n",
@ -7552,6 +7553,14 @@ int check_config_validity()
}
}
if (!curproxy->defbe.be && (curproxy->cap & PR_CAP_LISTEN) == PR_CAP_LISTEN) {
/* Case of listen without default backend
* The curproxy will be its own default backend
* so we update tot_fe_maxconn for a further
* fullconn's computation */
curproxy->tot_fe_maxconn += curproxy->maxconn;
}
/* find the target proxy for 'use_backend' rules */
list_for_each_entry(rule, &curproxy->switching_rules, list) {
struct proxy *target;
@ -7613,6 +7622,23 @@ int check_config_validity()
} else {
free((void *)rule->be.name);
rule->be.backend = target;
/* For each target of switching rules, we update
* their tot_fe_maxconn, except if a previous rule point
* on the same backend or on the default backend */
if (rule->be.backend != curproxy->defbe.be) {
struct switching_rule *swrule;
list_for_each_entry(swrule, &curproxy->switching_rules, list) {
if (rule == swrule) {
target->tot_fe_maxconn += curproxy->maxconn;
break;
}
else if (!swrule->dynamic && swrule->be.backend == rule->be.backend) {
/* there is multiple ref of this backend */
break;
}
}
}
}
}
@ -8869,48 +8895,11 @@ out_uri_auth_compat:
* the possible incoming frontend's maxconns.
*/
if (!curproxy->fullconn && (curproxy->cap & PR_CAP_BE)) {
struct proxy *fe;
int total = 0;
/* sum up the number of maxconns of frontends which
* reference this backend at least once or which are
* the same one ('listen').
*/
for (fe = proxy; fe; fe = fe->next) {
struct switching_rule *rule;
int found = 0;
if (!(fe->cap & PR_CAP_FE))
continue;
if (fe == curproxy) /* we're on a "listen" instance */
found = 1;
if (fe->defbe.be == curproxy) /* "default_backend" */
found = 1;
/* check if a "use_backend" rule matches */
if (!found) {
list_for_each_entry(rule, &fe->switching_rules, list) {
if (!rule->dynamic && rule->be.backend == curproxy) {
found = 1;
break;
}
}
}
/* now we've checked all possible ways to reference a backend
* from a frontend.
*/
if (!found)
continue;
total += fe->maxconn;
}
/* we have the sum of the maxconns in <total>. We only
* keep 10% of that sum to set the default fullconn, with
* a hard minimum of 1 (to avoid a divide by zero).
*/
curproxy->fullconn = (total + 9) / 10;
curproxy->fullconn = (curproxy->tot_fe_maxconn + 9) / 10;
if (!curproxy->fullconn)
curproxy->fullconn = 1;
}