Tari: more efficient polling

Use `GetTipInfo` gRPC call to quickly check for changes

src/merge_mining_client_tari.cpp

@@ -499,16 +499,47 @@ void MergeMiningClientTari::run()
 
 	using namespace std::chrono;
 
-	auto last_update_time = high_resolution_clock::now();
+	TipInfoResponse prev_tip_info{};
+	auto prev_tip_info_update_time = high_resolution_clock::now();
+
+	auto same_tip = [](const TipInfoResponse& a, const TipInfoResponse& b) -> bool {
+		return
+			(a.metadata().best_block_height() == b.metadata().best_block_height()) &&
+			(a.metadata().best_block_hash() == b.metadata().best_block_hash()) &&
+			(a.metadata().accumulated_difficulty() == b.metadata().accumulated_difficulty()) &&
+			(a.initial_sync_achieved() == b.initial_sync_achieved()) &&
+			(a.base_node_state() == b.base_node_state()) &&
+			(a.failed_checkpoints() == b.failed_checkpoints());
+	};
 
 	for (;;) {
-		const auto t1 = high_resolution_clock::now();
+		const auto start_time = high_resolution_clock::now();
+
+		// Force frequent enough updates (at least every 30 seconds)
+		if (duration_cast<seconds>(start_time - prev_tip_info_update_time).count() >= 30) {
+			prev_tip_info.mutable_metadata()->set_best_block_height(0);
+		}
 
 		MutexLock lock(m_workerLock);
 
-		GetNewBlockTemplateWithCoinbasesRequest request;
+		grpc::ClientContext get_tip_info_ctx{};
+		Empty get_tip_info_request{};
+		TipInfoResponse cur_tip_info{};
+
+		const grpc::Status get_tip_info_status = m_TariNode->GetTipInfo(&get_tip_info_ctx, get_tip_info_request, &cur_tip_info);
+
+		if (!get_tip_info_status.ok()) {
+			LOGWARN(4, "GetTipInfo failed: " << get_tip_info_status.error_message());
+			if (!get_tip_info_status.error_details().empty()) {
+				LOGWARN(4, "GetTipInfo failed: " << get_tip_info_status.error_details());
+			}
+		}
+		else if (!same_tip(cur_tip_info, prev_tip_info)) {
+			GetNewBlockTemplateWithCoinbasesRequest request{};
+
 			PowAlgo* algo = new PowAlgo();
 			algo->set_pow_algo(PowAlgo_PowAlgos_POW_ALGOS_RANDOMX);
+
 			request.clear_algo();
 			request.set_allocated_algo(algo);
 			request.set_max_weight(0);
@@ -523,8 +554,8 @@ void MergeMiningClientTari::run()
 			coinbase->set_revealed_value_proof(true);
 			coinbase->clear_coinbase_extra();
 
-		grpc::ClientContext ctx;
-		GetNewBlockResult response;
+			grpc::ClientContext ctx{};
+			GetNewBlockResult response{};
 
 			const grpc::Status status = m_TariNode->GetNewBlockTemplateWithCoinbases(&ctx, request, &response);
 
@@ -535,6 +566,9 @@ void MergeMiningClientTari::run()
 				}
 			}
 			else {
+				prev_tip_info = cur_tip_info;
+				prev_tip_info_update_time = start_time;
+
 				const std::string& id = response.tari_unique_id();
 				const std::string& mm_hash = response.merge_mining_hash();
 
@@ -563,16 +597,7 @@ void MergeMiningClientTari::run()
 						WriteLock lock2(m_chainParamsLock);
 
 						if (job_params != m_tariJobParams) {
-						// Don't update if only fees changed and it's been less than 10 seconds since the last update
-						if ((job_params.height == m_tariJobParams.height) &&
-							(job_params.diff == m_tariJobParams.diff) &&
-							(job_params.reward == m_tariJobParams.reward) &&
-							(duration_cast<milliseconds>(t1 - last_update_time).count() < 10'000)) {
-							break;
-						}
-
 							m_tariJobParams = job_params;
-						last_update_time = t1;
 
 							if (m_chainParams.aux_id.empty()) {
 								LOGINFO(1, m_hostStr << " uses chain_id " << log::LightCyan() << log::hex_buf(id.data(), id.size()));
@@ -600,8 +625,13 @@ void MergeMiningClientTari::run()
 					}
 				}
 			}
+		}
 
-		const int64_t timeout = std::max<int64_t>(500'000'000 - duration_cast<nanoseconds>(high_resolution_clock::now() - t1).count(), 1'000'000);
+		auto dt = duration_cast<nanoseconds>(high_resolution_clock::now() - start_time).count();
+
+		LOGINFO(6, "Polling loop took " << (static_cast<double>(dt) * 1e-6) << " ms");
+
+		const int64_t timeout = std::max<int64_t>(500'000'000 - dt, 1'000'000);
 
 		if ((m_workerStop.load() != 0) || (uv_cond_timedwait(&m_workerCond, &m_workerLock, timeout) != UV_ETIMEDOUT)) {
 			return;