This patch is generated from the rttpeer branch of HEAD in squid
Tue Aug 17 18:58:44 2004 GMT
See http://devel.squid-cache.org/
Index: squid/src/cf.data.pre
diff -u squid/src/cf.data.pre:1.78 squid/src/cf.data.pre:1.78.4.1
--- squid/src/cf.data.pre:1.78 Wed Aug 28 14:45:43 2002
+++ squid/src/cf.data.pre Sun Sep 1 07:18:43 2002
@@ -2795,6 +2795,24 @@
which are no more than this many rtt milliseconds away.
DOC_END
+NAME: minimum_direct_rtt_diff
+TYPE: int
+DEFAULT: 15
+LOC: Config.minDirectRttDiff
+DOC_START
+ If using the ICMP pinging stuff, do direct fetches for sites
+ which difference of RTT are no more than this many rtt milliseconds away.
+ The Difference of RTT is the difference between SOURCE RTT and PARENT FULL RTT(OR PARENT RTT when HIT).
+DOC_END
+
+NAME: minimum_fast_peer_rtt
+TYPE: int
+DEFAULT: 90
+LOC: Config.minFastPeerRtt
+DOC_START
+ if 0 < neighbor's RTT <= minimum_fast_peer_rtt, we consider this neighbor is the FAST neighbor.
+DOC_END
+
NAME: cachemgr_passwd
TYPE: cachemgrpasswd
DEFAULT: none
Index: squid/src/neighbors.c
diff -u squid/src/neighbors.c:1.19 squid/src/neighbors.c:1.19.4.1
--- squid/src/neighbors.c:1.19 Wed Aug 28 14:45:44 2002
+++ squid/src/neighbors.c Sun Sep 1 07:18:44 2002
@@ -682,7 +682,7 @@
choice_count++;
if (lookup == LOOKUP_MISS)
continue;
- p_rtt = netdbHostRtt(p->host);
+ p_rtt = p->stats.rtt; /* Change here! use RTT from local cache to peer when Cache Digest Hit, rather than RTT from parent cache to destination*/
debug(15, 5) ("neighborsDigestSelect: peer %s rtt: %d\n",
p->host, p_rtt);
/* is this peer better than others in terms of rtt ? */
@@ -1438,3 +1438,27 @@
mem->ping_reply_callback(p, ntype, PROTO_HTCP, htcp, mem->ircb_data);
}
#endif
+
+peer *
+getFastUpParent(request_t * request)
+{ /* This NEW public function perform getting the fastest Up Parent according to Parent's RTT */
+ peer *p = NULL, *p_min = NULL;
+ int rtt_min = 0;
+
+ for (p = Config.peers; p; p = p->next) {
+ if (!neighborUp(p))
+ continue;
+ if (neighborType(p, request) != PEER_PARENT)
+ continue;
+ if (!peerHTTPOkay(p, request))
+ continue;
+ if (p->stats.rtt == 0)
+ continue;
+
+ if (p->stats.rtt < rtt_min || rtt_min == 0) {
+ rtt_min = p->stats.rtt; /* get New Parent Peer with minimum RTT */
+ p_min = p;
+ }
+ }
+ return p_min;
+}
\ No newline at end of file
Index: squid/src/net_db.c
diff -u squid/src/net_db.c:1.15 squid/src/net_db.c:1.15.8.1
--- squid/src/net_db.c:1.15 Wed Jun 26 10:28:32 2002
+++ squid/src/net_db.c Sun Sep 1 07:18:44 2002
@@ -1091,11 +1091,13 @@
netdbClosestParent(request_t * request)
{
#if USE_ICMP
- peer *p = NULL;
+ peer *p = NULL, *p_min_rtt = NULL;
netdbEntry *n;
const ipcache_addrs *ia;
net_db_peer *h;
int i;
+ double rtt_min = 0, hops_min, full_rtt;
+
n = netdbLookupHost(request->host);
if (NULL == n) {
/* try IP addr */
@@ -1108,24 +1110,60 @@
if (0 == n->n_peers)
return NULL;
/*
- * Find the parent with the least RTT to the origin server.
+ * Find the parent with the least FULL RTT to the origin server.
* Make sure we don't return a parent who is farther away than
* we are. Note, the n->peers list is pre-sorted by RTT.
*/
for (i = 0; i < n->n_peers; i++) {
h = &n->peers[i];
- if (n->rtt > 0)
- if (n->rtt < h->rtt)
- break;
p = peerFindByName(h->peername);
if (NULL == p) /* not found */
continue;
+ if (p->stats.logged_state == PEER_DEAD) continue; /* a dead cache peer cannot be chosen */
if (neighborType(p, request) != PEER_PARENT)
continue;
if (!peerHTTPOkay(p, request)) /* not allowed */
continue;
- return p;
+ if (p->stats.rtt == 0) continue; /* cache peer RTT cannot be 0*/
+
+ full_rtt = p->stats.rtt + h->rtt; /* Note: full_rtt is always greater than Zero */
+ if (rtt_min && full_rtt > rtt_min) continue; /* cache peer FULL RTT is not minimum, search again*/
+ if (full_rtt == rtt_min) /* Peer with least hops is preferable, if both FULL RTT are equal */
+ if (h->hops >= hops_min) continue;
+
+ rtt_min = full_rtt; /* we get the NEW minimum FULL RTT */
+ hops_min = h->hops; /* we get new hops to source site */
+ p_min_rtt = p; /* we get the NEW peer with minimum FULL RTT */
}
-#endif
+ return p_min_rtt; /* choose the closest cache peer*/
+#else
return NULL;
+#endif
+}
+
+int
+netdbRtt(struct in_addr addr)
+{ /* Add New Public Function in net_db.c,it allow look up Host RTT by IP Address in Network DB*/
+#if USE_ICMP
+ netdbEntry *n = netdbLookupAddr(addr);
+ if (n) {
+ n->last_use_time = squid_curtime;
+ return (int) (n->rtt + 0.5);
+ }
+#endif
+ return 0;
+}
+
+int
+netdbPeerRtt(struct in_addr addr, peer * p)
+{ /* Add New Public Function in net_db.c,it allow look up Peer RTT by Host's IP Address in Network DB*/
+#if USE_ICMP
+ const netdbEntry *n = netdbLookupAddr(addr);
+ if (n) {
+ const net_db_peer *np = netdbPeerByName(n, p->host);
+ if (np && np->expires >= squid_curtime)
+ return (int) (np->rtt + 0.5);
+ }
+#endif
+ return 0;
}
Index: squid/src/peer_select.c
diff -u squid/src/peer_select.c:1.15 squid/src/peer_select.c:1.15.8.1
--- squid/src/peer_select.c:1.15 Sun Jun 23 07:57:13 2002
+++ squid/src/peer_select.c Sun Sep 1 07:18:44 2002
@@ -85,6 +85,7 @@
static void peerHandleHtcpReply(peer *, peer_t, htcpReplyData *, void *);
#endif
static int peerCheckNetdbDirect(ps_state * psstate);
+static int peerCheckNetdbDirectAgain(ps_state *, peer*, hier_code);
static void peerGetSomeNeighbor(ps_state *);
static void peerGetSomeNeighborReplies(ps_state *);
static void peerGetSomeDirect(ps_state *);
@@ -233,6 +234,83 @@
return 0;
}
+static int
+peerCheckNetdbDirectAgain(ps_state * ps, peer* p, hier_code code)
+{/* Check netdb again to make sure: whether peer is faster than direct access or not
+ Note: This function cannot be used for DIRECT_YES */
+ request_t *request = ps->request;
+ int n_rtt, h_rtt, full_rtt;
+ const ipcache_addrs *ia;
+ if (ps->direct == DIRECT_MAYBE) {
+ if (p->stats.logged_state == PEER_DEAD) return 1;
+ n_rtt = netdbHostRtt(request->host);
+ if (n_rtt == 0) { /* try IP addr again */
+ ia = ipcache_gethostbyname(request->host, 0);
+ if (NULL != ia) n_rtt = netdbRtt(ia->in_addrs[ia->cur]);
+ }
+
+ if (n_rtt) {
+ switch (code) {
+ case CLOSEST_PARENT:
+ case CLOSEST_PARENT_MISS:
+ case FIRST_PARENT_MISS:
+ case SOURCE_FASTEST:
+ h_rtt = netdbHostPeerRtt(request->host, p);
+ if (h_rtt == 0) { /* try IP addr again */
+ ia = ipcache_gethostbyname(request->host, 0);
+ if (NULL != ia) h_rtt = netdbPeerRtt(ia->in_addrs[ia->cur], p);
+ }
+ full_rtt = p->stats.rtt + h_rtt;
+ if (n_rtt <= full_rtt)
+ return 1; /* DIRECT ACCESS is preferable, by comparing FULL RTT with DIRECT RTT, and the smaller one will be preferable. */
+ if (full_rtt == 0) { /* Squid just start up AND no RTT data is found in netdb */
+ if (Config.onoff.prefer_direct) return 1;
+ } else if ((n_rtt - full_rtt) <= Config.minDirectRttDiff)
+ return 1; /* the difference is small enough to access source directly */
+ else if (h_rtt == 0 || p->stats.rtt == 0) /* full_rtt is actually HALF RTT, DIRECT ACCESS is preferable by Cache Administrator */
+ if (Config.onoff.prefer_direct) return 1;
+ break;
+ case CD_PARENT_HIT:
+ case CD_SIBLING_HIT:
+ case PARENT_HIT:
+ case SIBLING_HIT:
+ if (n_rtt <= p->stats.rtt)
+ return 1; /* DIRECT ACCESS is preferable, by comparing Peer RTT with DIRECT RTT, the smaller one will be preferable */
+ if (p->stats.rtt == 0) { /* Squid just start up */
+ if (Config.onoff.prefer_direct) return 1; /* DIRECT ACCESS is preferable by Cache Administrator */
+ } else if ((n_rtt - p->stats.rtt) <= Config.minDirectRttDiff)
+ return 1; /* the difference is small enough to access source directly */
+ default:
+ }
+ } else { /* when n_rtt == 0 , there are three reasons: 1. network is not reachable. 2. network admin of destination shut down ICMP echo. 3. no record is found in netdb */
+ switch (code) {
+ case CLOSEST_PARENT:
+ case CLOSEST_PARENT_MISS:
+ case FIRST_PARENT_MISS:
+ case SOURCE_FASTEST:
+ h_rtt = netdbHostPeerRtt(request->host, p);
+ if (h_rtt == 0) { /* try IP addr again */
+ ia = ipcache_gethostbyname(request->host, 0);
+ if (NULL != ia) h_rtt = netdbPeerRtt(ia->in_addrs[ia->cur], p);
+ }
+ if (h_rtt == 0)
+ if (Config.onoff.prefer_direct)
+ return 1; /* DIRECT ACCESS is preferable by Cache Administrator. */
+ break;
+ case CD_PARENT_HIT:
+ case CD_SIBLING_HIT:
+ case PARENT_HIT:
+ case SIBLING_HIT:
+ if (p->stats.rtt == 0 || p->stats.rtt > Config.minFastPeerRtt)
+ if (Config.onoff.prefer_direct)
+ return 1; /* If this HIT peer is not fast enough, DIRECT ACCESS is preferable by Cache Administrator */
+ default:
+ }
+ }
+ }
+ return 0;
+}
+
static void
peerSelectFoo(ps_state * ps)
{
@@ -293,12 +371,22 @@
peerGetAllParents(ps);
break;
default:
- if (Config.onoff.prefer_direct)
- peerGetSomeDirect(ps);
+ if (Config.onoff.prefer_direct) {
+ if (ps->servers) { /* avoid add DIRECT forward twice */
+ if (ps->servers->code != CLOSEST_DIRECT)
+ peerGetSomeDirect(ps);
+ }
+ else peerGetSomeDirect(ps);
+ }
if (request->flags.hierarchical || !Config.onoff.nonhierarchical_direct)
peerGetSomeParent(ps);
- if (!Config.onoff.prefer_direct)
- peerGetSomeDirect(ps);
+ if (!Config.onoff.prefer_direct) {
+ if (ps->servers) { /* avoid add DIRECT forward twice */
+ if (ps->servers->code != CLOSEST_DIRECT)
+ peerGetSomeDirect(ps);
+ }
+ else peerGetSomeDirect(ps);
+ }
break;
}
peerSelectCallback(ps);
@@ -361,6 +449,13 @@
}
if (code != HIER_NONE) {
assert(p);
+ if (ps->direct == DIRECT_MAYBE
+ #if USE_CARP
+ && code != CARP
+ #endif
+ )
+ if (peerCheckNetdbDirectAgain(ps, p, code))
+ peerAddFwdServer(&ps->servers, NULL, CLOSEST_DIRECT); /* Try Direct access First if possible*/
debug(44, 3) ("peerSelect: %s/%s\n", hier_strings[code], p->host);
peerAddFwdServer(&ps->servers, p, code);
}
@@ -402,6 +497,9 @@
code = FIRST_PARENT_MISS;
}
if (p && code != HIER_NONE) {
+ if (ps->direct == DIRECT_MAYBE)
+ if (peerCheckNetdbDirectAgain(ps, p, code))
+ peerAddFwdServer(&ps->servers, NULL, CLOSEST_DIRECT); /* try Direct Access First */
debug(44, 3) ("peerSelect: %s/%s\n", hier_strings[code], p->host);
peerAddFwdServer(&ps->servers, p, code);
}
@@ -432,6 +530,8 @@
peer *p;
request_t *request = ps->request;
hier_code code = HIER_NONE;
+ int n_rtt;
+ const ipcache_addrs *ia;
debug(44, 3) ("peerGetSomeParent: %s %s\n",
RequestMethodStr[request->method],
request->host);
@@ -447,12 +547,29 @@
code = ROUNDROBIN_PARENT;
} else if ((p = getWeightedRoundRobinParent(request))) {
code = ROUNDROBIN_PARENT;
+ } else if ((p = getFastUpParent(request))) {
+ code = CLOSEST_PARENT; /* the Fastest Parent we found */
} else if ((p = getFirstUpParent(request))) {
code = FIRSTUP_PARENT;
} else if ((p = getAnyParent(request))) {
code = ANY_OLD_PARENT;
}
if (code != HIER_NONE) {
+ if (ps->direct == DIRECT_MAYBE)
+ if (!ps->servers) {
+ /* Foward list is NULL, check which is better ? DIRECT ACCESS or Parent Peer*/
+ n_rtt = netdbHostRtt(request->host);
+ if (n_rtt == 0) { /* try IP addr again */
+ ia = ipcache_gethostbyname(request->host, 0);
+ if (NULL != ia) n_rtt = netdbRtt(ia->in_addrs[ia->cur]);
+ }
+ if (n_rtt) {
+ if (n_rtt <= p->stats.rtt)
+ peerAddFwdServer(&ps->servers, NULL, CLOSEST_DIRECT); /* DIRECT ACCESS is the First option*/
+ else if (p->stats.rtt && (n_rtt - p->stats.rtt) <= Config.minDirectRttDiff)
+ peerAddFwdServer(&ps->servers, NULL, CLOSEST_DIRECT); /* DIRECT ACCESS is the First option*/
+ }
+ }
debug(44, 3) ("peerSelect: %s/%s\n", hier_strings[code], p->host);
peerAddFwdServer(&ps->servers, p, code);
}
Index: squid/src/protos.h
diff -u squid/src/protos.h:1.59 squid/src/protos.h:1.59.8.1
--- squid/src/protos.h:1.59 Sat Jul 20 05:33:16 2002
+++ squid/src/protos.h Sun Sep 1 07:18:44 2002
@@ -644,7 +644,7 @@
/* Labels for hierachical log file */
/* put them all here for easier reference when writing a logfile analyzer */
-
+extern peer *getFastUpParent(request_t *);
extern peer *getFirstPeer(void);
extern peer *getFirstUpParent(request_t *);
extern peer *getNextPeer(peer *);
@@ -689,6 +689,8 @@
extern void netdbPingSite(const char *hostname);
extern void netdbDump(StoreEntry *);
extern int netdbHops(struct in_addr);
+extern int netdbRtt(struct in_addr);
+extern int netdbPeerRtt(struct in_addr, peer *);
extern void netdbFreeMemory(void);
extern int netdbHostHops(const char *host);
extern int netdbHostRtt(const char *host);
Index: squid/src/structs.h
diff -u squid/src/structs.h:1.64 squid/src/structs.h:1.64.4.1
--- squid/src/structs.h:1.64 Wed Aug 28 14:45:44 2002
+++ squid/src/structs.h Sun Sep 1 07:18:44 2002
@@ -535,6 +535,8 @@
} fqdncache;
int minDirectHops;
int minDirectRtt;
+ int minDirectRttDiff; /* minimum difference between SOURCE RTT and FULL RTT(OR parent RTT) */
+ int minFastPeerRtt;
cachemgr_passwd *passwd_list;
struct {
int objectsPerBucket;