Store when the last getwork was retrieved and display it in the API summary.

api.c

@@ -1920,6 +1920,7 @@ static void summary(struct io_data *io_data, __maybe_unused SOCKETTYPE c, __mayb
 	double stalep = (total_diff_accepted + total_diff_rejected + total_diff_stale) ?
 			(double)(total_diff_stale) / (double)(total_diff_accepted + total_diff_rejected + total_diff_stale) : 0;
 	root = api_add_percent(root, "Pool Stale%", &stalep, false);
+	root = api_add_time(root, "Last getwork", &last_getwork, false);
 
 	mutex_unlock(&hash_lock);
 

miner.h

@@ -976,6 +976,7 @@ extern int opt_api_port;
 extern bool opt_api_listen;
 extern bool opt_api_network;
 extern bool opt_delaynet;
+extern time_t last_getwork;
 extern bool opt_restart;
 extern bool opt_worktime;
 extern int swork_id;

sgminer.c

@@ -95,6 +95,7 @@ int opt_expiry = 28;
 static const bool opt_time = true;
 unsigned long long global_hashrate;
 unsigned long global_quota_gcd = 1;
+time_t last_getwork;
 
 int nDevs;
 int opt_dynamic_interval = 7;
@@ -5899,6 +5900,7 @@ struct work *get_work(struct thr_info *thr, const int thr_id)
 			wake_gws();
 		}
 	}
+	last_getwork = time(NULL);
 	applog(LOG_DEBUG, "Got work from get queue to get work for thread %d", thr_id);
 
 	work->thr_id = thr_id;