[IO] add option to advance the io_urings's cq for each processed cqe

emper/Emper.hpp

@@ -66,6 +66,14 @@ static const bool IO_TRY_SYSCALL =
 #endif
 		;
 
+static const bool IO_BATCH_CQE =
+#ifdef EMPER_IO_BATCH_CQE
+		true
+#else
+		false
+#endif
+		;
+
 static const bool IO_URING_SQPOLL =
 #ifdef EMPER_IO_URING_SQPOLL
 		true

emper/io/IoContext.cpp

@@ -166,6 +166,10 @@ void IoContext::completer_func() {
 			}
 
 			future->try_complete<CallerEnvironment::ANYWHERE>(cqe->res);
+
+			if constexpr (!emper::IO_BATCH_CQE) {
+				break;
+			}
 		}
 
 		LOGD("got " << count << " cqes from the io_uring");

meson_options.txt

@@ -70,6 +70,12 @@ option(
   value: true,
   description: 'Try to complete IO request with a syscall before submitting it to the io_uring'
 )
+option(
+  'io_batch_cqe',
+  type: 'boolean',
+  value: true,
+  description: 'Don't advance the io_uring's cq for each processed'
+)
 option(
   'io_peek_optimization',
   type: 'boolean',