diff --git a/passes/techmap/extract_fa.cc b/passes/techmap/extract_fa.cc
index 1984f82f5..964ec99bc 100644
--- a/passes/techmap/extract_fa.cc
+++ b/passes/techmap/extract_fa.cc
@@ -19,7 +19,11 @@
 
 #include "kernel/yosys.h"
 #include "kernel/sigtools.h"
+#include "backends/rtlil/rtlil_backend.h"
 #include "kernel/consteval.h"
+#include <cstdio>
+#include <mutex>
+#include <thread>
 
 USING_YOSYS_NAMESPACE
 PRIVATE_NAMESPACE_BEGIN
@@ -66,9 +70,6 @@ struct ExtractFaWorker
 	dict<tuple<SigBit, SigBit>, dict<int, pool<SigBit>>> func2;
 	dict<tuple<SigBit, SigBit, SigBit>, dict<int, pool<SigBit>>> func3;
 
-	int count_func2;
-	int count_func3;
-
 	struct func2_and_info_t {
 		bool inv_a, inv_b, inv_y;
 	};
@@ -77,6 +78,26 @@ struct ExtractFaWorker
 		bool inv_a, inv_b, inv_c, inv_y;
 	};
 
+	struct Counters {
+		int count_func2;
+		int count_func3;
+	};
+
+	struct ThreadData {
+		size_t start;
+		size_t end;
+		Counters counters;
+		ExtractFaWorker* instance;
+		std::stringstream log_buffer;
+		std::vector<RTLIL::IdString> ports = {ID::A, ID::B, ID::C, ID::D};
+		pool<tuple<SigBit, SigBit>> tl_xorxnor2;
+		pool<tuple<SigBit, SigBit, SigBit>> tl_xorxnor3;
+		pool<tuple<tuple<SigBit, SigBit>, int, SigBit>> tl_func_2;
+		pool<tuple<tuple<SigBit, SigBit, SigBit>,int, SigBit>> tl_func_3;
+	};
+
+	std::mutex consteval_mtx;
+
 	dict<int, func2_and_info_t> func2_and_info;
 	dict<int, func3_maj_info_t> func3_maj_info;
 
@@ -153,7 +174,7 @@ struct ExtractFaWorker
 		}
 	}
 
-	void check_partition(SigBit root, pool<SigBit> &leaves)
+	void check_partition(SigBit root, pool<SigBit> &leaves, ThreadData& data)
 	{
 		if (config.enable_ha && GetSize(leaves) == 2)
 		{
@@ -163,35 +184,38 @@ struct ExtractFaWorker
 			SigBit B = SigSpec(leaves)[1];
 
 			int func = 0;
-			for (int i = 0; i < 4; i++)
 			{
-				bool a_value = (i & 1) != 0;
-				bool b_value = (i & 2) != 0;
+				std::lock_guard lock(consteval_mtx);
+				for (int i = 0; i < 4; i++)
+				{
+					bool a_value = (i & 1) != 0;
+					bool b_value = (i & 2) != 0;
 
-				ce.push();
-				ce.set(A, a_value ? State::S1 : State::S0);
-				ce.set(B, b_value ? State::S1 : State::S0);
+					ce.push();
+					ce.set(A, a_value ? State::S1 : State::S0);
+					ce.set(B, b_value ? State::S1 : State::S0);
+					SigSpec sig = root;
 
-				SigSpec sig = root;
+					if (!ce.eval(sig)) {
+						ce.pop();
+						return;
+					}
+
+					if (sig == State::S1)
+						func |= 1 << i;
 
-				if (!ce.eval(sig)) {
 					ce.pop();
-					return;
 				}
-
-				if (sig == State::S1)
-					func |= 1 << i;
-
-				ce.pop();
 			}
-
 			// log("%04d %s %s -> %s\n", bindec(func), log_signal(A), log_signal(B), log_signal(root));
 
 			if (func == xor2_func || func == xnor2_func)
-				xorxnor2.insert(tuple<SigBit, SigBit>(A, B));
+				data.tl_xorxnor2.insert(tuple<SigBit, SigBit>(A, B));
 
-			count_func2++;
-			func2[tuple<SigBit, SigBit>(A, B)][func].insert(root);
+			data.counters.count_func2++;
+			data.tl_func_2.insert(
+				tuple<tuple<SigBit, SigBit>, int, SigBit>(tuple<SigBit, SigBit>(A, B), func, root)
+			);
 		}
 
 		if (config.enable_fa && GetSize(leaves) == 3)
@@ -203,52 +227,70 @@ struct ExtractFaWorker
 			SigBit C = SigSpec(leaves)[2];
 
 			int func = 0;
-			for (int i = 0; i < 8; i++)
 			{
-				bool a_value = (i & 1) != 0;
-				bool b_value = (i & 2) != 0;
-				bool c_value = (i & 4) != 0;
+				std::lock_guard lock(consteval_mtx);
+				for (int i = 0; i < 8; i++)
+				{
+					bool a_value = (i & 1) != 0;
+					bool b_value = (i & 2) != 0;
+					bool c_value = (i & 4) != 0;
 
-				ce.push();
-				ce.set(A, a_value ? State::S1 : State::S0);
-				ce.set(B, b_value ? State::S1 : State::S0);
-				ce.set(C, c_value ? State::S1 : State::S0);
+					ce.push();
+					ce.set(A, a_value ? State::S1 : State::S0);
+					ce.set(B, b_value ? State::S1 : State::S0);
+					ce.set(C, c_value ? State::S1 : State::S0);
+					SigSpec sig = root;
 
-				SigSpec sig = root;
+					if (!ce.eval(sig)) {
+						ce.pop();
+						return;
+					}
+					if (sig == State::S1)
+						func |= 1 << i;
 
-				if (!ce.eval(sig)) {
 					ce.pop();
-					return;
 				}
-
-				if (sig == State::S1)
-					func |= 1 << i;
-
-				ce.pop();
 			}
 
 			// log("%08d %s %s %s -> %s\n", bindec(func), log_signal(A), log_signal(B), log_signal(C), log_signal(root));
 
 			if (func == xor3_func || func == xnor3_func)
-				xorxnor3.insert(tuple<SigBit, SigBit, SigBit>(A, B, C));
+				data.tl_xorxnor3.insert(tuple<SigBit, SigBit, SigBit>(A, B, C));
 
-			count_func3++;
-			func3[tuple<SigBit, SigBit, SigBit>(A, B, C)][func].insert(root);
+			data.counters.count_func3++;
+			data.tl_func_3.insert(
+				tuple<tuple<SigBit, SigBit, SigBit>, int, SigBit>(tuple<SigBit, SigBit, SigBit>(A, B, C), func, root)
+			);
 		}
 	}
+	void partition_log_cache(std::stringstream& stream, int depth, SigBit signal, bool format_depth=false) {
+		std::stringstream buf;
+		RTLIL_BACKEND::dump_sigspec(buf, signal, true);
+		if(format_depth) {
+			// at most, this is going to take in maxdepth spaces + 2 brackets + 2 numbers + space + \0
+			std::vector<char> spacer_buffer;
+			spacer_buffer.resize(config.maxdepth + 6);
+			snprintf(spacer_buffer.data(), config.maxdepth + 6, "%*s[%d] ", config.maxdepth-depth, "", depth);
+			stream << spacer_buffer.data();
+		}
 
-	void find_partitions(SigBit root, pool<SigBit> &leaves, pool<pool<SigBit>> &cache, int maxdepth, int maxbreadth)
+		stream << " " << buf.str();
+		if(format_depth)
+			stream << ":";
+	}
+
+	void find_partitions(SigBit root, pool<SigBit> &leaves, pool<pool<SigBit>> &cache, int maxdepth, int maxbreadth, ThreadData& data)
 	{
 		if (cache.count(leaves))
 			return;
 
-		// log("%*s[%d] %s:", 20-maxdepth, "", maxdepth, log_signal(root));
-		// for (auto bit : leaves)
-		// 	log(" %s", log_signal(bit));
-		// log("\n");
+		partition_log_cache(data.log_buffer, maxdepth, root, true);
+		for (auto bit : leaves)
+			partition_log_cache(data.log_buffer, maxdepth, bit);
+		data.log_buffer << "\n";
 
 		cache.insert(leaves);
-		check_partition(root, leaves);
+		check_partition(root, leaves, data);
 
 		if (maxdepth == 0)
 			return;
@@ -262,7 +304,8 @@ struct ExtractFaWorker
 			pool<SigBit> new_leaves = leaves;
 
 			new_leaves.erase(bit);
-			for (auto port : {ID::A, ID::B, ID::C, ID::D}) {
+
+			for (auto port : data.ports) {
 				if (!cell->hasPort(port))
 					continue;
 				auto bit = sigmap(SigBit(cell->getPort(port)));
@@ -274,7 +317,7 @@ struct ExtractFaWorker
 			if (GetSize(new_leaves) > maxbreadth)
 				continue;
 
-			find_partitions(root, new_leaves, cache, maxdepth-1, maxbreadth);
+			find_partitions(root, new_leaves, cache, maxdepth-1, maxbreadth, data);
 		}
 	}
 
@@ -290,29 +333,55 @@ struct ExtractFaWorker
 	void run()
 	{
 		log("Extracting full/half adders from %s:\n", log_id(module));
+		const size_t num_threads = std::thread::hardware_concurrency();
+		std::vector<std::thread> threads;
+		std::vector<ThreadData> thread_data(num_threads);
 
-		for (auto it : driver)
-		{
-			if (it.second->type.in(ID($_BUF_), ID($_NOT_)))
-				continue;
+		size_t total_elements = driver.size();
+		size_t thread_elements = total_elements / num_threads;
+		for (size_t i = 0; i < num_threads; ++i) {
+			thread_data[i].start = i * thread_elements;
+			thread_data[i].end = (i == num_threads - 1) ? total_elements : (i + 1) * thread_elements;
+			thread_data[i].instance = this;
 
-			SigBit root = it.first;
-			pool<SigBit> leaves = { root };
-			pool<pool<SigBit>> cache;
+			threads.emplace_back([&data = thread_data[i]]() {
+				auto& driver = data.instance->driver;
+				auto& config = data.instance->config;
 
-			if (config.verbose)
-				log("  checking %s\n", log_signal(it.first));
+				for (size_t i = data.start; i < data.end; ++i) {
+					const auto& it = *driver.element(i);
+					if (it.second->type.in(ID($_BUF_), ID($_NOT_)))
+						continue;
 
-			count_func2 = 0;
-			count_func3 = 0;
+					SigBit root = it.first;
+					pool<SigBit> leaves = { root };
+					pool<pool<SigBit>> cache;
 
-			find_partitions(root, leaves, cache, config.maxdepth, config.maxbreadth);
+					if (config.verbose)
+						log("  checking %s\n", log_signal(it.first));
 
-			if (config.verbose && count_func2 > 0)
-				log("    extracted %d two-input functions\n", count_func2);
+					data.instance->find_partitions(root, leaves, cache, config.maxdepth, config.maxbreadth, data);
+					// log("%s", log_buffer.str().c_str());
 
-			if (config.verbose && count_func3 > 0)
-				log("    extracted %d three-input functions\n", count_func3);
+					if (config.verbose && data.counters.count_func2 > 0)
+						log("    extracted %d two-input functions\n", data.counters.count_func2);
+
+					if (config.verbose && data.counters.count_func3 > 0)
+						log("    extracted %d three-input functions\n", data.counters.count_func3);
+				}
+			});
+		}
+
+		for (size_t i = 0; i < num_threads; ++i) {
+			threads[i].join();
+			for(auto& x3 : thread_data[i].tl_xorxnor3)
+				xorxnor3.insert(x3);
+			for(auto& x2 : thread_data[i].tl_xorxnor2)
+				xorxnor2.insert(x2);
+			for(auto& f3 : thread_data[i].tl_func_3)
+				func3[get<0>(f3)][get<1>(f3)].insert(get<2>(f3));
+			for(auto& f2 : thread_data[i].tl_func_2)
+				func2[get<0>(f2)][get<1>(f2)].insert(get<2>(f2));
 		}
 
 		for (auto &key : xorxnor3)
@@ -341,10 +410,13 @@ struct ExtractFaWorker
 				int func = it.first;
 				auto f3i = it.second;
 
+				int xor_cnt, xnor_cnt;
+				xor_cnt = func3.at(key).count(xor3_func);
+				xnor_cnt = func3.at(key).count(xnor3_func);
 				if (func3.at(key).count(func) == 0)
 					continue;
 
-				if (func3.at(key).count(xor3_func) == 0 && func3.at(key).count(xnor3_func) != 0) {
+				if (xor_cnt == 0 && xnor_cnt != 0) {
 					f3i.inv_a = !f3i.inv_a;
 					f3i.inv_b = !f3i.inv_b;
 					f3i.inv_c = !f3i.inv_c;
@@ -413,13 +485,13 @@ struct ExtractFaWorker
 				}
 
 				bool invert_y = f3i.inv_a ^ f3i.inv_b ^ f3i.inv_c;
-				if (func3.at(key).count(xor3_func)) {
+				if (xor_cnt) {
 					SigBit YY = invert_xy ^ invert_y ? module->NotGate(NEW_ID, Y) : Y;
 					for (auto bit : func3.at(key).at(xor3_func))
 						assign_new_driver(bit, YY);
 				}
 
-				if (func3.at(key).count(xnor3_func)) {
+				if (xnor_cnt) {
 					SigBit YY = invert_xy ^ invert_y ? Y : module->NotGate(NEW_ID, Y);
 					for (auto bit : func3.at(key).at(xnor3_func))
 						assign_new_driver(bit, YY);