From abce89b981d568b3277501c1e4c656f66fec0655 Mon Sep 17 00:00:00 2001
From: Sean McBride <spmcbride1201@gmail.com>
Date: Sun, 11 Oct 2020 15:27:04 -0400
Subject: [PATCH] feat: Expose scheduler as runtime config

---
 runtime/include/runtime.h   | 19 +++++++++++++++++++
 runtime/src/main.c          | 19 +++++++++++++++++++
 runtime/src/runtime.c       | 13 +++++++++++--
 runtime/src/worker_thread.c | 12 ++++++++++--
 4 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/runtime/include/runtime.h b/runtime/include/runtime.h
index c9e76fa..3e4d7a4 100644
--- a/runtime/include/runtime.h
+++ b/runtime/include/runtime.h
@@ -95,3 +95,22 @@ runtime_is_worker()
 
 	return false;
 }
+
+enum RUNTIME_SCHEDULER
+{
+	RUNTIME_SCHEDULER_FIFO = 0,
+	RUNTIME_SCHEDULER_EDF  = 1
+};
+
+static inline char *
+print_runtime_scheduler(enum RUNTIME_SCHEDULER variant)
+{
+	switch (variant) {
+	case RUNTIME_SCHEDULER_FIFO:
+		return "RUNTIME_SCHEDULER_FIFO";
+	case RUNTIME_SCHEDULER_EDF:
+		return "RUNTIME_SCHEDULER_EDF";
+	}
+};
+
+extern enum RUNTIME_SCHEDULER runtime_scheduler;
diff --git a/runtime/src/main.c b/runtime/src/main.c
index 312b26a..07e1be1 100644
--- a/runtime/src/main.c
+++ b/runtime/src/main.c
@@ -28,6 +28,7 @@ uint32_t runtime_first_worker_processor                       = 0;
 int runtime_worker_threads_argument[WORKER_THREAD_CORE_COUNT] = { 0 }; /* The worker sets its argument to -1 on error */
 pthread_t runtime_worker_threads[WORKER_THREAD_CORE_COUNT];
 
+enum RUNTIME_SCHEDULER runtime_scheduler = RUNTIME_SCHEDULER_FIFO;
 
 /**
  * Returns instructions on use of CLI if used incorrectly
@@ -183,6 +184,22 @@ runtime_start_runtime_worker_threads()
 	exit(-1);
 }
 
+void
+runtime_configure()
+{
+	/* Scheduler Policy */
+	char *scheduler_policy = getenv("SLEDGE_SCHEDULER");
+	if (scheduler_policy == NULL) scheduler_policy = "FIFO";
+
+	if (strcmp(scheduler_policy, "EDF") == 0) {
+		runtime_scheduler = RUNTIME_SCHEDULER_EDF;
+	} else if (strcmp(scheduler_policy, "FIFO") == 0) {
+		runtime_scheduler = RUNTIME_SCHEDULER_FIFO;
+	} else {
+		panic("Invalid scheduler policy: %s. Must be {EDF|FIFO}\n", scheduler_policy);
+	}
+}
+
 int
 main(int argc, char **argv)
 {
@@ -209,12 +226,14 @@ main(int argc, char **argv)
 
 	runtime_set_resource_limits_to_max();
 	runtime_allocate_available_cores();
+	runtime_configure();
 	runtime_initialize();
 #ifdef LOG_MODULE_LOADING
 	debuglog("Parsing modules file [%s]\n", argv[1]);
 #endif
 	if (module_new_from_json(argv[1])) panic("failed to parse modules file[%s]\n", argv[1]);
 
+	debuglog("Scheduler Policy: %s\n", print_runtime_scheduler(runtime_scheduler));
 	debuglog("Starting listener thread\n");
 	listener_thread_initialize();
 	debuglog("Starting worker threads\n");
diff --git a/runtime/src/runtime.c b/runtime/src/runtime.c
index 365fa95..157e476 100644
--- a/runtime/src/runtime.c
+++ b/runtime/src/runtime.c
@@ -122,8 +122,17 @@ runtime_initialize(void)
 	/* Allocate and Initialize the global deque
 	TODO: Improve to expose variant as a config #Issue 93
 	*/
-	// global_request_scheduler_deque_initialize();
-	global_request_scheduler_minheap_initialize();
+
+	switch (runtime_scheduler) {
+	case RUNTIME_SCHEDULER_EDF:
+		global_request_scheduler_minheap_initialize();
+		break;
+	case RUNTIME_SCHEDULER_FIFO:
+		global_request_scheduler_deque_initialize();
+		break;
+	default:
+		panic("Invalid scheduler policy set: %u\n", runtime_scheduler);
+	}
 
 	/* Mask Signals */
 	software_interrupt_mask_signal(SIGUSR1);
diff --git a/runtime/src/worker_thread.c b/runtime/src/worker_thread.c
index 2652c30..391bf78 100644
--- a/runtime/src/worker_thread.c
+++ b/runtime/src/worker_thread.c
@@ -344,8 +344,16 @@ worker_thread_main(void *return_code)
 	arch_context_init(&worker_thread_base_context, 0, 0);
 
 	/* Initialize Runqueue Variant */
-	// local_runqueue_list_initialize();
-	local_runqueue_minheap_initialize();
+	switch (runtime_scheduler) {
+	case RUNTIME_SCHEDULER_EDF:
+		local_runqueue_minheap_initialize();
+		break;
+	case RUNTIME_SCHEDULER_FIFO:
+		local_runqueue_list_initialize();
+		break;
+	default:
+		panic("Invalid scheduler policy set: %u\n", runtime_scheduler);
+	}
 
 	/* Initialize Completion Queue */
 	local_completion_queue_initialize();