fine tuning by using the irq fast lane

arch/x86/kernel/irq.c

@@ -275,13 +275,10 @@ void irq_handler(struct state *s)
 #endif
 
 leave_handler:
-#ifdef CONFIG_ROCKCREEK
-	// add fast lane for the driver task
-	if (s->int_no >= 32)
-		scheduler();
-#else
 	// timer interrupt?
 	if ((s->int_no == 32) || (s->int_no == 123))
 		scheduler(); // switch to a new task
-#endif
+	// exists a new (driver) task with a higher priority?
+	else if ((s->int_no >= 32) && (get_highest_priority(CORE_ID) > per_core(current_task)->prio))
+		scheduler();
 }

include/metalsvm/tasks.h

@@ -176,6 +176,13 @@ size_t get_idle_task(uint32_t id);
  */
 int sys_execve(const char* fname, char** argv, char** env);
 
+/** @brief determines the highest priority of all ready tasks on core core_id
+ *
+ * @param core_id core id
+ * @return highest priority 
+ */
+uint32_t get_highest_priority(uint32_t core_id);
+
 /** @brief Call to rescheduling
  *
  * This is a purely assembled procedure for rescheduling

kernel/tasks.c

@@ -68,6 +68,10 @@ task_t* get_current_task(void) {
 	return per_core(current_task);
 }
 
+uint32_t get_highest_priority(uint32_t core_id) {
+	return last_set(runqueues[core_id].prio_bitmap);
+}
+
 int multitasking_init(void) {
 	if (BUILTIN_EXPECT(task_table[0].status != TASK_IDLE, 0)) {
 		kputs("Task 0 is not an idle task\n");