Implement a new pool strategy, BALANCE, which monitors work performed per pool as a rolling average every 10 minutes to try and distribute work evenly over all the pools.

Do this by monitoring diff1 solutions to allow different difficulty target pools to be treated equally, along with solo mining.
Update the documentation to describe this strategy and more accurately describe the load-balance one.

README

@@ -141,12 +141,13 @@ Options for both config file and command line:
 --api-port          Port number of miner API (default: 4028)
 --auto-fan          Automatically adjust all GPU fan speeds to maintain a target temperature
 --auto-gpu          Automatically adjust all GPU engine clock speeds to maintain a target temperature
+--balance           Change multipool strategy from failover to even share balance
 --benchmark         Run cgminer in benchmark mode - produces no shares
 --debug|-D          Enable debug output
 --expiry|-E <arg>   Upper bound on how many seconds after getting work we consider a share from it stale (default: 120)
 --failover-only     Don't leak work to backup pools when primary pool is lagging
 --kernel-path|-K <arg> Specify a path to where bitstream and kernel files are (default: "/usr/local/bin")
---load-balance      Change multipool strategy from failover to even load balance
+--load-balance      Change multipool strategy from failover to efficiency based balance
 --log|-l <arg>      Interval in seconds between log output (default: 5)
 --monitor|-m <arg>  Use custom pipe cmd for output messages
 --net-delay         Impose small delays in networking to not overload slow routers
@@ -425,8 +426,14 @@ This strategy moves at user-defined intervals from one active pool to the next,
 skipping pools that are idle.
 
 LOAD BALANCE:
-This strategy sends work in equal amounts to all the pools specified. If any
+This strategy sends work to all the pools to maintain optimum load. The most
-pool falls idle, the rest will take up the slack keeping the miner busy.
+efficient pools will tend to get a lot more shares. If any pool falls idle, the
+rest will tend to take up the slack keeping the miner busy.
+
+BALANCE:
+This strategy monitors the amount of difficulty 1 shares solved for each pool
+and uses it to try to end up doing the same amount of work for all pools.
+
 
 ---
 LOGGING

cgminer.c

@@ -78,6 +78,7 @@ struct strategies strategies[] = {
 	{ "Round Robin" },
 	{ "Rotate" },
 	{ "Load Balance" },
+	{ "Balance" },
 };
 
 static char packagename[255];
@@ -513,6 +514,12 @@ static char *set_devices(char *arg)
 	return NULL;
 }
 
+static char *set_balance(enum pool_strategy *strategy)
+{
+	*strategy = POOL_BALANCE;
+	return NULL;
+}
+
 static char *set_loadbalance(enum pool_strategy *strategy)
 {
 	*strategy = POOL_LOADBALANCE;
@@ -783,6 +790,9 @@ static struct opt_table opt_config_table[] = {
 			opt_set_bool, &opt_autoengine,
 			"Automatically adjust all GPU engine clock speeds to maintain a target temperature"),
 #endif
+	OPT_WITHOUT_ARG("--balance",
+		     set_balance, &pool_strategy,
+		     "Change multipool strategy from failover to even share balance"),
 	OPT_WITHOUT_ARG("--benchmark",
 			opt_set_bool, &opt_benchmark,
 			"Run cgminer in benchmark mode - produces no shares"),
@@ -889,7 +899,7 @@ static struct opt_table opt_config_table[] = {
 #endif
 	OPT_WITHOUT_ARG("--load-balance",
 		     set_loadbalance, &pool_strategy,
-		     "Change multipool strategy from failover to even load balance"),
+		     "Change multipool strategy from failover to efficiency based balance"),
 	OPT_WITH_ARG("--log|-l",
 		     set_int_0_to_9999, opt_show_intval, &opt_log_interval,
 		     "Interval in seconds between log output"),
@@ -1455,7 +1465,7 @@ static void curses_print_status(void)
 		global_queued(), total_staged(), total_stale, total_discarded, new_blocks,
 		local_work, total_go, total_ro);
 	wclrtoeol(statuswin);
-	if (pool_strategy == POOL_LOADBALANCE && total_pools > 1)
+	if ((pool_strategy == POOL_LOADBALANCE  || pool_strategy == POOL_BALANCE) && total_pools > 1)
 		mvwprintw(statuswin, 4, 0, " Connected to multiple pools with%s LP",
 			have_longpoll ? "": "out");
 	else
@@ -1905,6 +1915,31 @@ out_nofree:
 static const char *rpc_req =
 	"{\"method\": \"getwork\", \"params\": [], \"id\":0}\r\n";
 
+/* In balanced mode, the amount of diff1 solutions per pool is monitored as a
+ * rolling average per 10 minutes and if pools start getting more, it biases
+ * away from them to distribute work evenly. The share count is reset to the
+ * rolling average every 10 minutes to not send all work to one pool after it
+ * has been disabled/out for an extended period. */
+static struct pool *select_balanced(struct pool *cp)
+{
+	int i, lowest = cp->shares;
+	struct pool *ret = cp;
+
+	for (i = 0; i < total_pools; i++) {
+		struct pool *pool = pools[i];
+
+		if (pool->idle || pool->enabled != POOL_ENABLED)
+			continue;
+		if (pool->shares < lowest) {
+			lowest = pool->shares;
+			ret = pool;
+		}
+	}
+
+	ret->shares++;
+	return ret;
+}
+
 /* Select any active pool in a rotating fashion when loadbalance is chosen */
 static inline struct pool *select_pool(bool lagging)
 {
@@ -1913,6 +1948,9 @@ static inline struct pool *select_pool(bool lagging)
 
 	cp = current_pool();
 
+	if (pool_strategy == POOL_BALANCE)
+		return select_balanced(cp);
+
 	if (pool_strategy != POOL_LOADBALANCE && (!lagging || opt_fail_only))
 		pool = cp;
 	else
@@ -2248,7 +2286,7 @@ static inline bool should_roll(struct work *work)
 	struct timeval now;
 	time_t expiry;
 
-	if (work->pool != current_pool() && pool_strategy != POOL_LOADBALANCE)
+	if (work->pool != current_pool() && pool_strategy != POOL_LOADBALANCE && pool_strategy != POOL_BALANCE)
 		return false;
 
 	if (work->rolltime > opt_scantime)
@@ -2468,7 +2506,8 @@ static bool stale_work(struct work *work, bool share)
 		return true;
 	}
 
-	if (opt_fail_only && !share && pool != current_pool() && !work->mandatory) {
+	if (opt_fail_only && !share && pool != current_pool() && !work->mandatory &&
+	    pool_strategy != POOL_LOADBALANCE && pool_strategy != POOL_BALANCE) {
 		applog(LOG_DEBUG, "Work stale due to fail only pool mismatch");
 		return true;
 	}
@@ -2609,6 +2648,7 @@ void switch_pools(struct pool *selected)
 
 	switch (pool_strategy) {
 		/* Both of these set to the master pool */
+		case POOL_BALANCE:
 		case POOL_FAILOVER:
 		case POOL_LOADBALANCE:
 			for (i = 0; i < total_pools; i++) {
@@ -3171,6 +3211,8 @@ void write_config(FILE *fcfg)
 
 	/* Special case options */
 	fprintf(fcfg, ",\n\"shares\" : \"%d\"", opt_shares);
+	if (pool_strategy == POOL_BALANCE)
+		fputs(",\n\"balance\" : true", fcfg);
 	if (pool_strategy == POOL_LOADBALANCE)
 		fputs(",\n\"load-balance\" : true", fcfg);
 	if (pool_strategy == POOL_ROUNDROBIN)
@@ -4160,6 +4202,8 @@ bool test_nonce(struct work *work, uint32_t nonce)
 
 bool submit_nonce(struct thr_info *thr, struct work *work, uint32_t nonce)
 {
+	work->pool->diff1++;
+
 	/* Do one last check before attempting to submit the work */
 	/* Side effect: sets work->data for us */
 	if (!test_nonce(work, nonce)) {
@@ -4447,10 +4491,10 @@ static struct pool *select_longpoll_pool(struct pool *cp)
  */
 static void wait_lpcurrent(struct pool *pool)
 {
-	if (pool->enabled == POOL_REJECTING || pool_strategy == POOL_LOADBALANCE)
+	if (pool->enabled == POOL_REJECTING || pool_strategy == POOL_LOADBALANCE || pool_strategy == POOL_BALANCE)
 		return;
 
-	while (pool != current_pool() && pool_strategy != POOL_LOADBALANCE) {
+	while (pool != current_pool() && pool_strategy != POOL_LOADBALANCE && pool_strategy != POOL_BALANCE) {
 		mutex_lock(&lp_lock);
 		pthread_cond_wait(&lp_cond, &lp_lock);
 		mutex_unlock(&lp_lock);
@@ -4588,12 +4632,16 @@ static void reap_curl(struct pool *pool)
 
 static void *watchpool_thread(void __maybe_unused *userdata)
 {
+	int intervals = 0;
+
 	pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
 
 	while (42) {
 		struct timeval now;
 		int i;
 
+		if (++intervals > 20)
+			intervals = 0;
 		gettimeofday(&now, NULL);
 
 		for (i = 0; i < total_pools; i++) {
@@ -4610,6 +4658,15 @@ static void *watchpool_thread(void __maybe_unused *userdata)
 				if (pool_active(pool, true) && pool_tclear(pool, &pool->idle))
 					pool_resus(pool);
 			}
+
+			/* Get a rolling utility per pool over 10 mins */
+			if (intervals > 19) {
+				int shares = pool->diff1 - pool->last_shares;
+
+				pool->last_shares = pool->diff1;
+				pool->utility = (pool->utility + (double)shares * 0.63) / 1.63;
+				pool->shares = pool->utility;
+			}
 		}
 
 		if (pool_strategy == POOL_ROTATE && now.tv_sec - rotate_tv.tv_sec > 60 * opt_rotate_period) {
@@ -4618,6 +4675,7 @@ static void *watchpool_thread(void __maybe_unused *userdata)
 		}
 
 		sleep(30);
+			
 	}
 	return NULL;
 }

miner.h

@@ -173,9 +173,10 @@ enum pool_strategy {
 	POOL_ROUNDROBIN,
 	POOL_ROTATE,
 	POOL_LOADBALANCE,
+	POOL_BALANCE,
 };
 
-#define TOP_STRATEGY (POOL_LOADBALANCE)
+#define TOP_STRATEGY (POOL_BALANCE)
 
 struct strategies {
 	const char *s;
@@ -723,6 +724,7 @@ struct pool {
 	int accepted, rejected;
 	int seq_rejects;
 	int solved;
+	int diff1;
 
 	bool submit_fail;
 	bool idle;
@@ -743,6 +745,9 @@ struct pool {
 	unsigned int remotefail_occasions;
 	struct timeval tv_idle;
 
+	double utility;
+	int last_shares, shares;
+
 	char *rpc_url;
 	char *rpc_userpass;
 	char *rpc_user, *rpc_pass;