/*
- * $Id: cache_cf.cc,v 1.401 2002/03/09 22:43:12 hno Exp $
+ * $Id: cache_cf.cc,v 1.402 2002/04/04 21:03:46 hno Exp $
*
* DEBUG: section 3 Configuration File Parsing
* AUTHOR: Harvest Derived
} else if (!strcasecmp(token, "no-netdb-exchange")) {
p->options.no_netdb_exchange = 1;
#if USE_CARP
- } else if (!strncasecmp(token, "carp-load-factor=", 17)) {
+ } else if (!strcasecmp(token, "carp")) {
if (p->type != PEER_PARENT)
- debug(3, 0) ("parse_peer: Ignoring carp-load-factor for non-parent %s/%d\n", p->host, p->http_port);
- else
- p->carp.load_factor = atof(token + 17);
+ fatalf("parse_peer: non-parent carp peer %s/%d\n", p->host, p->http_port);
+ p->options.carp = 1;
#endif
#if DELAY_POOLS
} else if (!strcasecmp(token, "no-delay")) {
p->icp.version = ICP_VERSION_CURRENT;
p->tcp_up = PEER_TCP_MAGIC_COUNT;
p->test_fd = -1;
-#if USE_CARP
-#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
- if (p->carp.load_factor) {
- /* calculate this peers hash for use in CARP */
- p->carp.hash = 0;
- for (token = p->host; *token != 0; token++)
- p->carp.hash += ROTATE_LEFT(p->carp.hash, 19) + (unsigned int) *token;
- p->carp.hash += p->carp.hash * 0x62531965;
- p->carp.hash = ROTATE_LEFT(p->carp.hash, 21);
- }
-#endif
#if USE_CACHE_DIGESTS
if (!p->options.no_digest) {
p->digest = peerDigestCreate(p);
/*
- * $Id: carp.cc,v 1.15 2001/01/12 00:37:15 wessels Exp $
+ * $Id: carp.cc,v 1.16 2002/04/04 21:03:46 hno Exp $
*
* DEBUG: section 39 Cache Array Routing Protocol
- * AUTHOR: Eric Stern
+ * AUTHOR: Henrik Nordstrom
+ * BASED ON: carp.c by Eric Stern and draft-vinod-carp-v1-03.txt
*
* SQUID Web Proxy Cache http://www.squid-cache.org/
* ----------------------------------------------------------
#if USE_CARP
+#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
+
+static int n_carp_peers = 0;
+static peer **carp_peers = NULL;
static OBJH carpCachemgr;
+static int
+peerSortWeight(const void *a, const void *b)
+{
+ const peer *const *p1 = a, *const *p2 = b;
+ return (*p1)->weight - (*p2)->weight;
+}
+
void
carpInit(void)
{
- /* calculate load factors */
- int K = 0;
- double a = 0.0;
- double dJ;
- double Xn;
- double P_last;
- double X_last;
+ int W = 0;
+ int K;
int k;
+ double P_last, X_last, Xn;
peer *p;
+ peer **P;
+ char *t;
+ /* Clean up */
+ for (k = 0; k < n_carp_peers; k++) {
+ cbdataUnlock(carp_peers[k]);
+ }
+ safe_free(carp_peers);
+ n_carp_peers = 0;
+ /* find out which peers we have */
for (p = Config.peers; p; p = p->next) {
- a += p->carp.load_factor;
- K++;
+ if (!p->options.carp)
+ continue;
+ assert(p->type == PEER_PARENT);
+ if (p->weight == 0)
+ continue;
+ n_carp_peers++;
+ W += p->weight;
}
- if (a == 0.0) {
- for (p = Config.peers; p; p = p->next)
- p->carp.load_multiplier = 1.0;
+ if (n_carp_peers == 0)
return;
+ carp_peers = xcalloc(n_carp_peers, sizeof(*carp_peers));
+ /* Build a list of the found peers and calculate hashes and load factors */
+ for (P = carp_peers, p = Config.peers; p; p = p->next) {
+ if (!p->options.carp)
+ continue;
+ if (p->weight == 0)
+ continue;
+ /* calculate this peers hash */
+ p->carp.hash = 0;
+ for (t = p->host; *t != 0; t++)
+ p->carp.hash += ROTATE_LEFT(p->carp.hash, 19) + (unsigned int) *t;
+ p->carp.hash += p->carp.hash * 0x62531965;
+ p->carp.hash = ROTATE_LEFT(p->carp.hash, 21);
+ /* and load factor */
+ p->carp.load_factor = ((double) p->weight) / (double) W;
+ if (floor(p->carp.load_factor * 1000.0) == 0.0)
+ p->carp.load_factor = 0.0;
+ /* add it to our list of peers */
+ *P++ = p;
+ cbdataLock(p);
}
- /*
- * sum of carp-load-factor's for all cache_peer's in squid.conf
- * must equal 1.0. If this doesn't work, see
- * http://www.eskimo.com/~scs/C-faq/q14.4.html
+ /* Sort our list on weight */
+ qsort(carp_peers, n_carp_peers, sizeof(*carp_peers), peerSortWeight);
+ /* Calculate the load factor multipliers X_k
+ *
+ * X_1 = pow ((K*p_1), (1/K))
+ * X_k = ([K-k+1] * [P_k - P_{k-1}])/(X_1 * X_2 * ... * X_{k-1})
+ * X_k += pow ((X_{k-1}, {K-k+1})
+ * X_k = pow (X_k, {1/(K-k+1)})
+ * simplified to have X_1 part of the loop
*/
- assert(1000 == (int) (1000.0 * a));
- k = 1;
- P_last = 0;
- p = Config.peers;
- p->carp.load_multiplier = pow(p->carp.load_factor * K, 1.0 / K);
- Xn = p->carp.load_multiplier;
- P_last = p->carp.load_factor;
- X_last = p->carp.load_multiplier;
- if (!p->next)
- return;
- for (p = p->next; p; p = p->next) {
- k++;
- dJ = (double) (K - k + 1);
- p->carp.load_multiplier = (dJ * (p->carp.load_factor - P_last)) / Xn;
- p->carp.load_multiplier += pow(X_last, dJ);
- p->carp.load_multiplier = pow(p->carp.load_multiplier, 1 / dJ);
+ K = n_carp_peers;
+ P_last = 0.0; /* Empty P_0 */
+ Xn = 1.0; /* Empty starting point of X_1 * X_2 * ... * X_{x-1} */
+ X_last = 0.0; /* Empty X_0, nullifies the first pow statement */
+ for (k = 1; k <= K; k++) {
+ double Kk1 = (double) (K - k + 1);
+ p = carp_peers[k - 1];
+ p->carp.load_multiplier = (Kk1 * (p->carp.load_factor - P_last)) / Xn;
+ p->carp.load_multiplier += pow(X_last, Kk1);
+ p->carp.load_multiplier = pow(p->carp.load_multiplier, 1.0 / Kk1);
Xn *= p->carp.load_multiplier;
X_last = p->carp.load_multiplier;
P_last = p->carp.load_factor;
peer *
carpSelectParent(request_t * request)
{
-#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (((sizeof(unsigned long)*8)-(n)))))
+ int k;
const char *c;
peer *p = NULL;
peer *tp;
- unsigned long url_hash = 0;
- unsigned long combined_hash;
- unsigned long high_score = 0;
- const char *url = urlCanonical(request);
- /* calculate url hash */
- debug(39, 2) ("carpSelectParent: CARP Calculating hash for %s\n", url);
- for (c = url; *c != 0; c++)
- url_hash += ROTATE_LEFT(url_hash, 19) + *c;
+ unsigned int user_hash = 0;
+ unsigned int combined_hash;
+ double score;
+ double high_score = 0;
+ char *key = NULL;
+
+ if (n_carp_peers == 0)
+ return NULL;
+
+ key = urlCanonical(url);
+
+ /* calculate hash key */
+ debug(39, 2) ("carpSelectParent: Calculating hash for %s\n", key);
+ for (c = key; *c != 0; c++)
+ user_hash += ROTATE_LEFT(user_hash, 19) + *c;
/* select peer */
- for (tp = Config.peers; tp; tp = tp->next) {
- if (0.0 == tp->carp.load_factor)
- continue;
- if (tp->tcp_up != PEER_TCP_MAGIC_COUNT)
- continue;
- assert(tp->type == PEER_PARENT);
- combined_hash = (url_hash ^ tp->carp.hash);
+ for (k = 0; k < n_carp_peers; k++) {
+ tp = carp_peers[k];
+ combined_hash = (user_hash ^ tp->carp.hash);
combined_hash += combined_hash * 0x62531965;
combined_hash = ROTATE_LEFT(combined_hash, 21);
- combined_hash = combined_hash * tp->carp.load_multiplier;
- debug(39, 3) ("carpSelectParent: %s combined_hash %d\n",
- tp->host, combined_hash);
- if ((combined_hash > high_score) && neighborUp(tp)) {
+ score = combined_hash * tp->carp.load_multiplier;
+ debug(39, 3) ("carpSelectParent: %s combined_hash %u score %.0f\n",
+ tp->host, combined_hash, score);
+ if ((score > high_score) && peerHTTPOkay(tp, request)) {
p = tp;
- high_score = combined_hash;
+ high_score = score;
}
}
if (p)
- debug(39, 3) ("carpSelectParent: selected CARP %s\n", p->host);
+ debug(39, 2) ("carpSelectParent: selected %s\n", p->host);
return p;
}
p->carp.load_factor,
sumfetches ? (double) p->stats.fetches / sumfetches : -1.0);
}
-
}
#endif
projects / thirdparty / squid.git / commitdiff
