Cache the binary generation of coinbase1 and 2 on stratum, avoiding a hex2bin of coinbase1 and 2 on each work generation.

cgminer.c

@@ -5611,10 +5611,10 @@ static void gen_stratum_work(struct pool *pool, struct work *work)
 	coinbase = calloc(alloc_len, 1);
 	if (unlikely(!coinbase))
 		quit(1, "Failed to calloc coinbase in gen_stratum_work");
-	hex2bin(coinbase, pool->swork.coinbase1, pool->swork.cb1_len);
+	memcpy(coinbase, pool->swork.cb1, pool->swork.cb1_len);
 	hex2bin(coinbase + pool->swork.cb1_len, pool->nonce1, pool->n1_len);
 	hex2bin(coinbase + pool->swork.cb1_len + pool->n1_len, work->nonce2, pool->n2size);
-	hex2bin(coinbase + pool->swork.cb1_len + pool->n1_len + pool->n2size, pool->swork.coinbase2, pool->swork.cb2_len);
+	memcpy(coinbase + pool->swork.cb1_len + pool->n1_len + pool->n2size, pool->swork.cb2, pool->swork.cb2_len);
 
 	/* Generate merkle root */
 	gen_hash(coinbase, merkle_root, pool->swork.cb_len);

miner.h

@@ -1066,6 +1066,8 @@ struct stratum_work {
 	char *nbit;
 	char *ntime;
 	bool clean;
+	unsigned char *cb1;
+	unsigned char *cb2;
 
 	size_t cb1_len;
 	size_t cb2_len;

util.c

@@ -1277,6 +1277,17 @@ static bool parse_notify(struct pool *pool, json_t *val)
 	/* workpadding */	 96;
 	pool->swork.header_len = pool->swork.header_len * 2 + 1;
 	align_len(&pool->swork.header_len);
+
+	free(pool->swork.cb1);
+	free(pool->swork.cb2);
+	pool->swork.cb1 = calloc(pool->swork.cb1_len, 1);
+	if (unlikely(!pool->swork.cb1))
+		quit(1, "Failed to calloc swork cb1 in parse_notify");
+	hex2bin(pool->swork.cb1, pool->swork.coinbase1, pool->swork.cb1_len);
+	pool->swork.cb2 = calloc(pool->swork.cb2_len, 1);
+	if (unlikely(!pool->swork.cb2))
+		quit(1, "Failed to calloc swork cb2 in parse_notify");
+	hex2bin(pool->swork.cb2, pool->swork.coinbase2, pool->swork.cb2_len);
 	cg_wunlock(&pool->data_lock);
 
 	if (opt_protocol) {