Author: rjung
Date: Thu Sep 22 21:17:03 2011
New Revision: 1174394
URL: http://svn.apache.org/viewvc?rev=1174394&view=rev
Log:
New LB balancing method "Next" to distribute
sessions in a round-robin way.
Modified:
tomcat/jk/trunk/native/common/jk_lb_worker.c
tomcat/jk/trunk/native/common/jk_lb_worker.h
tomcat/jk/trunk/native/common/jk_status.c
tomcat/jk/trunk/xdocs/miscellaneous/changelog.xml
tomcat/jk/trunk/xdocs/reference/status.xml
tomcat/jk/trunk/xdocs/reference/workers.xml
Modified: tomcat/jk/trunk/native/common/jk_lb_worker.c
URL:
http://svn.apache.org/viewvc/tomcat/jk/trunk/native/common/jk_lb_worker.c?rev=1174394&r1=1174393&r2=1174394&view=diff
==============================================================================
--- tomcat/jk/trunk/native/common/jk_lb_worker.c (original)
+++ tomcat/jk/trunk/native/common/jk_lb_worker.c Thu Sep 22 21:17:03 2011
@@ -185,6 +185,8 @@ int jk_lb_get_method_code(const char *v)
return JK_LB_METHOD_BUSYNESS;
else if (*v == 's' || *v == 'S' || *v == '3')
return JK_LB_METHOD_SESSIONS;
+ else if (*v == 'n' || *v == 'N' || *v == '4')
+ return JK_LB_METHOD_NEXT;
else
return JK_LB_METHOD_DEF;
}
@@ -619,14 +621,21 @@ static jk_uint64_t decay_load(lb_worker_
{
unsigned int i;
jk_uint64_t curmax = 0;
+ jk_uint64_t curmin;
lb_sub_worker_t *w;
ajp_worker_t *aw;
JK_TRACE_ENTER(l);
+ curmin = (&p->lb_workers[0])->s->lb_value;
for (i = 0; i < p->num_of_workers; i++) {
w = &p->lb_workers[i];
if (p->lbmethod != JK_LB_METHOD_BUSYNESS) {
- w->s->lb_value >>= exponent;
+ if (p->lbmethod != JK_LB_METHOD_NEXT) {
+ w->s->lb_value >>= exponent;
+ }
+ if (w->s->lb_value < curmin) {
+ curmin = w->s->lb_value;
+ }
if (w->s->lb_value > curmax) {
curmax = w->s->lb_value;
}
@@ -634,6 +643,12 @@ static jk_uint64_t decay_load(lb_worker_
aw = (ajp_worker_t *)w->worker->worker_private;
aw->s->reply_timeouts >>= exponent;
}
+ if (p->lbmethod == JK_LB_METHOD_NEXT) {
+ for (i = 0; i < p->num_of_workers; i++) {
+ w = &p->lb_workers[i];
+ w->s->lb_value -= curmin;
+ }
+ }
JK_TRACE_EXIT(l);
return curmax;
}
@@ -1219,10 +1234,11 @@ static int JK_METHOD service(jk_endpoint
rec->s->busy++;
if (p->worker->s->busy > p->worker->s->max_busy)
p->worker->s->max_busy = p->worker->s->busy;
- if ( (p->worker->lbmethod == JK_LB_METHOD_REQUESTS) ||
- (p->worker->lbmethod == JK_LB_METHOD_BUSYNESS) ||
- (p->worker->lbmethod == JK_LB_METHOD_SESSIONS &&
- !sessionid) )
+ if (p->worker->lbmethod == JK_LB_METHOD_REQUESTS ||
+ p->worker->lbmethod == JK_LB_METHOD_BUSYNESS ||
+ (!sessionid &&
+ (p->worker->lbmethod == JK_LB_METHOD_SESSIONS ||
+ p->worker->lbmethod == JK_LB_METHOD_NEXT)))
rec->s->lb_value += rec->lb_mult;
if (p->worker->lblock == JK_LB_LOCK_PESSIMISTIC)
jk_shm_unlock();
Modified: tomcat/jk/trunk/native/common/jk_lb_worker.h
URL:
http://svn.apache.org/viewvc/tomcat/jk/trunk/native/common/jk_lb_worker.h?rev=1174394&r1=1174393&r2=1174394&view=diff
==============================================================================
--- tomcat/jk/trunk/native/common/jk_lb_worker.h (original)
+++ tomcat/jk/trunk/native/common/jk_lb_worker.h Thu Sep 22 21:17:03 2011
@@ -44,12 +44,14 @@ extern "C"
#define JK_LB_METHOD_TRAFFIC (1)
#define JK_LB_METHOD_BUSYNESS (2)
#define JK_LB_METHOD_SESSIONS (3)
+#define JK_LB_METHOD_NEXT (4)
#define JK_LB_METHOD_DEF (JK_LB_METHOD_REQUESTS)
-#define JK_LB_METHOD_MAX (JK_LB_METHOD_SESSIONS)
+#define JK_LB_METHOD_MAX (JK_LB_METHOD_NEXT)
#define JK_LB_METHOD_TEXT_REQUESTS ("Request")
#define JK_LB_METHOD_TEXT_TRAFFIC ("Traffic")
#define JK_LB_METHOD_TEXT_BUSYNESS ("Busyness")
#define JK_LB_METHOD_TEXT_SESSIONS ("Sessions")
+#define JK_LB_METHOD_TEXT_NEXT ("Next")
#define JK_LB_METHOD_TEXT_DEF (JK_LB_METHOD_TEXT_REQUESTS)
#define JK_LB_LOCK_OPTIMISTIC (0)
#define JK_LB_LOCK_PESSIMISTIC (1)
Modified: tomcat/jk/trunk/native/common/jk_status.c
URL:
http://svn.apache.org/viewvc/tomcat/jk/trunk/native/common/jk_status.c?rev=1174394&r1=1174393&r2=1174394&view=diff
==============================================================================
--- tomcat/jk/trunk/native/common/jk_status.c (original)
+++ tomcat/jk/trunk/native/common/jk_status.c Thu Sep 22 21:17:03 2011
@@ -2720,6 +2720,12 @@ static void form_worker(jk_ws_service_t
if (lb->lbmethod == JK_LB_METHOD_SESSIONS)
jk_puts(s, " checked=\"checked\"");
jk_puts(s, "/></td></tr>\n");
+ jk_putv(s, "<tr><td> Next</td><td><input name=\"",
+ JK_STATUS_ARG_LB_METHOD, "\" type=\"radio\"", NULL);
+ jk_printf(s, " value=\"%d\"", JK_LB_METHOD_NEXT);
+ if (lb->lbmethod == JK_LB_METHOD_NEXT)
+ jk_puts(s, " checked=\"checked\"");
+ jk_puts(s, "/></td></tr>\n");
jk_putv(s, "<tr><td>", JK_STATUS_ARG_LB_TEXT_LOCK,
":</td><td></td></tr>\n", NULL);
jk_putv(s, "<tr><td> Optimistic</td><td><input name=\"",
Modified: tomcat/jk/trunk/xdocs/miscellaneous/changelog.xml
URL:
http://svn.apache.org/viewvc/tomcat/jk/trunk/xdocs/miscellaneous/changelog.xml?rev=1174394&r1=1174393&r2=1174394&view=diff
==============================================================================
--- tomcat/jk/trunk/xdocs/miscellaneous/changelog.xml (original)
+++ tomcat/jk/trunk/xdocs/miscellaneous/changelog.xml Thu Sep 22 21:17:03 2011
@@ -53,6 +53,10 @@
variable JK_STICKY_IGNORE. This can be useful to break cookie
stickyness
for non-sticky requests like login forms. (rjung)
</add>
+ <add>
+ LB: New balancing method "Next" to distribute sessions in a round-robin
+ way. (rjung)
+ </add>
</changelog>
</subsection>
</section>
Modified: tomcat/jk/trunk/xdocs/reference/status.xml
URL:
http://svn.apache.org/viewvc/tomcat/jk/trunk/xdocs/reference/status.xml?rev=1174394&r1=1174393&r2=1174394&view=diff
==============================================================================
--- tomcat/jk/trunk/xdocs/reference/status.xml (original)
+++ tomcat/jk/trunk/xdocs/reference/status.xml Thu Sep 22 21:17:03 2011
@@ -487,7 +487,7 @@ contain the configuration information, y
<b>vlf</b>: sticky_session_force (0/f/n/off=off, 1/t/y/on=on; case insensitive)
</li>
<li>
-<b>vlm</b>: method (0/r="Requests", 1/t="Traffic", 2/b="Busyness",
3/s="Sessions"; case insensitive, only first character is used)
+<b>vlm</b>: method (0/r="Requests", 1/t="Traffic", 2/b="Busyness",
3/s="Sessions", 4/s="Next"; case insensitive, only first character is used)
</li>
<li>
<b>vll</b>: lock (0/o="Optimistic", 1/p="Pessimistic"; case insensitive, only
first character is used)
Modified: tomcat/jk/trunk/xdocs/reference/workers.xml
URL:
http://svn.apache.org/viewvc/tomcat/jk/trunk/xdocs/reference/workers.xml?rev=1174394&r1=1174393&r2=1174394&view=diff
==============================================================================
--- tomcat/jk/trunk/xdocs/reference/workers.xml (original)
+++ tomcat/jk/trunk/xdocs/reference/workers.xml Thu Sep 22 21:17:03 2011
@@ -536,13 +536,13 @@ setting of worker.maintain. The value of
using the status worker.
</p>
<p>
-If method is set to <b>R[equest]</b> the balancer will use number of requests
+If method is set to <b>R[equest]</b> the balancer will use the number of
requests
to find the best worker. Accesses will be distributed according to the
lbfactor in a sliding time window. This is the default value and should be
working well for most applications.
</p>
<p>
-If method is set to <b>S[ession]</b> the balancer will use number of sessions
+If method is set to <b>S[ession]</b> the balancer will use the number of
sessions
to find the best worker. Accesses will be distributed according to the
lbfactor in a sliding time window. Because the balancer does not keep any
state,
it actually does not know the number of sessions. Instead it counts each
request
@@ -553,6 +553,18 @@ if sessions are your limiting resource,
and your sessions need a lot of memory.
</p>
<p>
+If method is set to <b>N[ext]</b> the balancer will again use the number of
sessions
+to find the best worker. The difference to the <b>S[ession]</b> method is how
+the session count is handled in the sliding time window. The <b>N[ext]</b>
method
+does not divide by 2, instead it subtracts the minimum number. This should
effectively
+result in a round-robin session balancing, thus the name <b>N[ext]</b>.
+Under high load, the two session balancing
+methods will result in a similar distribution, but <b>N[ext]</b> will be better
+if you need to distribute small numbers of sessions. Again this method will
+neither know, when a session is being invalidated, nor will it correct its
load numbers
+according to session timeouts or worker failover.
+</p>
+<p>
If set to <b>T[raffic]</b> the balancer will use
the network traffic between JK and Tomcat to find the best worker.
Accesses will be distributed according to the lbfactor in a sliding time
window.
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