Semi-feature port form 2.6/2.7.
This is a direct port of Marks logic changes to clear round-robin
counters periodically and after a peering change.
ref: http://www.squid-cache.org/bugs/show_bug.cgi?id=2376
Amos
--
Please use Squid 2.7.STABLE3 or 3.0.STABLE7
=== modified file 'src/cache_cf.cc'
--- src/cache_cf.cc 2008-07-11 19:32:10 +0000
+++ src/cache_cf.cc 2008-07-13 13:18:41 +0000
@@ -1850,7 +1850,7 @@
*head = p;
- peerClearRR(p);
+ peerClearRRStart();
}
static void
=== modified file 'src/neighbors.cc'
--- src/neighbors.cc 2008-06-12 12:49:29 +0000
+++ src/neighbors.cc 2008-07-13 12:52:56 +0000
@@ -384,19 +384,67 @@
return q;
}
-/* This gets called every 5 minutes to clear the round-robin counter. */
-void
-peerClearRR(void *data)
-{
- peer *p = (peer *)data;
- p->rr_count -= p->rr_lastcount;
-
- if (p->rr_count < 0)
+/**
+ * This gets called every 5 minutes to clear the round-robin counter.
+ * The exact timing is an arbitrary default, set on estimate timing of a
+ * large number of requests in a high-performance environment during the
+ * period. The larger the number of requests between cycled resets the
+ * more balanced the operations.
+ *
+ \param data unused.
+ \todo Make the reset timing a selectable parameter in squid.conf
+ */
+static void
+peerClearRRLoop(void *data)
+{
+ peerClearRR();
+ eventAdd("peerClearRR", peerClearRRLoop, data, 5 * 60.0, 0);
+}
+
+/**
+ * This gets called on startup and restart to kick off the peer round-robin
+ * maintenance event. It ensures that no matter how many times its called
+ * no more than one event is scheduled.
+ */
+void
+peerClearRRStart(void)
+{
+ static int event_added = 0;
+ if (!event_added) {
+ peerClearRRLoop(NULL);
+ }
+}
+
+/**
+ * Called whenever the round-robin counters need to be reset to a sane state.
+ * So far those times are:
+ \item On startup and reconfigure - to set the counters to sane initial settings.
+ \item When a peer has revived from dead, to prevent the revived peer being
+ * flooded with requests which it has 'missed' during the down period.
+ */
+void
+peerClearRR()
+{
+ peer *p = NULL;
+ for (p = Config.peers; p; p = p->next) {
p->rr_count = 0;
-
- p->rr_lastcount = p->rr_count;
-
- eventAdd("peerClearRR", peerClearRR, p, 5 * 60.0, 0);
+ }
+}
+
+/**
+ * Perform all actions when a peer is detected revived.
+ */
+void
+peerAlive(peer *p)
+{
+ if (p->stats.logged_state == PEER_DEAD && p->tcp_up) {
+ debugs(15, 1, "Detected REVIVED " << neighborTypeStr(p) << ": " << p->name);
+ p->stats.logged_state = PEER_ALIVE;
+ peerClearRR();
+ }
+
+ p->stats.last_reply = squid_curtime;
+ p->stats.probe_start = 0;
}
peer *
@@ -862,13 +910,7 @@
static void
neighborAlive(peer * p, const MemObject * mem, const icp_common_t * header)
{
- if (p->stats.logged_state == PEER_DEAD && p->tcp_up) {
- debugs(15, 1, "Detected REVIVED " << neighborTypeStr(p) << ": " << p->name);
- p->stats.logged_state = PEER_ALIVE;
- }
-
- p->stats.last_reply = squid_curtime;
- p->stats.probe_start = 0;
+ peerAlive(p);
p->stats.pings_acked++;
if ((icp_opcode) header->opcode <= ICP_END)
@@ -906,14 +948,7 @@
static void
neighborAliveHtcp(peer * p, const MemObject * mem, const htcpReplyData * htcp)
{
- if (p->stats.logged_state == PEER_DEAD && p->tcp_up) {
- debugs(15, 1, "Detected REVIVED " << neighborTypeStr(p) << ": " << p->name);
- p->stats.logged_state = PEER_ALIVE;
- }
-
- p->stats.last_reply = squid_curtime;
- p->stats.probe_start = 0;
- p->stats.pings_acked++;
+ peerAlive(p);
p->htcp.counts[htcp->hit ? 1 : 0]++;
p->htcp.version = htcp->version;
}
@@ -1322,13 +1357,13 @@
{
if (!p->tcp_up) {
debugs(15, 2, "TCP connection to " << p->host << "/" << p->http_port << " succeded");
- debugs(15, 1, "Detected REVIVED " << neighborTypeStr(p) << ": " << p->name);
- p->stats.logged_state = PEER_ALIVE;
+ p->tcp_up = PEER_TCP_MAGIC_COUNT; // NP: so peerAlive(p) works properly.
+ peerAlive(p);
if (!p->n_addresses)
ipcache_nbgethostbyname(p->host, peerDNSConfigure, p);
}
-
- p->tcp_up = PEER_TCP_MAGIC_COUNT;
+ else
+ p->tcp_up = PEER_TCP_MAGIC_COUNT;
}
static void
=== modified file 'src/protos.h'
--- src/protos.h 2008-07-11 19:32:10 +0000
+++ src/protos.h 2008-07-13 12:54:28 +0000
@@ -397,7 +397,8 @@
SQUIDCEXTERN peer *getDefaultParent(HttpRequest * request);
SQUIDCEXTERN peer *getRoundRobinParent(HttpRequest * request);
SQUIDCEXTERN peer *getWeightedRoundRobinParent(HttpRequest * request);
-SQUIDCEXTERN void peerClearRR(void *);
+SQUIDCEXTERN void peerClearRRStart(void);
+SQUIDCEXTERN void peerClearRR(void);
SQUIDCEXTERN peer *getAnyParent(HttpRequest * request);
SQUIDCEXTERN lookup_t peerDigestLookup(peer * p, HttpRequest * request);
SQUIDCEXTERN peer *neighborsDigestSelect(HttpRequest * request);
=== modified file 'src/structs.h'
--- src/structs.h 2008-07-11 19:32:10 +0000
+++ src/structs.h 2008-07-13 12:47:40 +0000
@@ -961,7 +961,6 @@
IPAddress addresses[10];
int n_addresses;
int rr_count;
- int rr_lastcount;
peer *next;
int test_fd;
