Merge branch 'shared-wq' into 'master'

[IO] add option to use a common async backend for all io_urings

See merge request i4/manycore/emper!94

emper/Emper.hpp

@@ -89,4 +89,12 @@ static const bool IO_URING_SQPOLL =
 		false
 #endif
 		;
+
+static const bool IO_URING_SHARED_WQ =
+#ifdef EMPER_IO_URING_SHARED_WQ
+		true
+#else
+		false
+#endif
+		;
 }	 // namespace emper

emper/Runtime.hpp

@@ -58,7 +58,7 @@ class Runtime : public Logger<LogSubsystem::RUNTI> {
 	ContextManager& contextManager;
 	pthread_t* threads;
 	Worker** workers;
-	IoContext* globalIo;
+	IoContext* globalIo = nullptr;
 	IoContext* ioContexts;
 
 	std::default_random_engine randomEngine;

emper/io/IoContext.cpp

@@ -351,6 +351,14 @@ IoContext::IoContext(size_t uring_entries) {
 		params.flags |= IORING_SETUP_SQPOLL;
 	}
 
+	if constexpr (emper::IO_URING_SHARED_WQ) {
+		auto *gio = getGlobalIo();
+		if (gio) {
+			params.flags |= IORING_SETUP_ATTACH_WQ;
+			params.wq_fd = gio->ring.ring_fd;
+		}
+	}
+
 	auto ret = io_uring_queue_init_params(uring_entries, &ring, &params);
 	if (ret < 0) {
 		DIE_MSG_ERRNO("io_uring_queue_init failed");

meson.build

@@ -56,6 +56,7 @@ endif
 
 io_bool_options = [
 	'uring_sqpoll',
+	'uring_shared_wq',
 ]
 
 io_raw_options = [

meson_options.txt

@@ -92,3 +92,9 @@ option(
   value: false,
   description: 'Enable io_urings SQPOLL feature (start a separate kernel thread which polls the sq reducing the amount of syscalls to submit new requests. This is a privileged operation.).'
 )
+option(
+  'io_uring_shared_wq',
+  type: 'boolean',
+  value: false,
+  description: 'Share a common async backend between all io_urings'
+)