From c309099e79a23ef02ee7d24d0d214d5b0a269efe Mon Sep 17 00:00:00 2001
From: Themaister <maister@archlinux.us>
Date: Tue, 18 Sep 2012 21:51:50 +0200
Subject: [PATCH] Attempt to use SCHED_FIFO in KMS.

This is mostly for testing purposes, to see how much scheduling affects
performance.
---
 gfx/context/drm_egl_ctx.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/gfx/context/drm_egl_ctx.c b/gfx/context/drm_egl_ctx.c
index 07e160f5f1..fbf5289ea9 100644
--- a/gfx/context/drm_egl_ctx.c
+++ b/gfx/context/drm_egl_ctx.c
@@ -30,6 +30,8 @@
 #include <signal.h>
 #include <stdint.h>
 #include <signal.h>
+#include <unistd.h>
+#include <sched.h>
 
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
@@ -236,6 +238,37 @@ void gfx_ctx_get_video_size(unsigned *width, unsigned *height)
    *height = g_fb_height;
 }
 
+static void reschedule_process(void)
+{
+   struct sched_param param = {0};
+
+   // All-out real-time. Why not? :D
+   param.sched_priority = sched_get_priority_max(SCHED_FIFO);
+   if (sched_setscheduler(0, SCHED_FIFO, &param) < 0)
+      RARCH_ERR("[KMS/EGL]: Failed to set SCHED_FIFO priority.\n");
+
+   int sched = sched_getscheduler(getpid());
+
+   const char *scheduler;
+   switch (sched)
+   {
+      case SCHED_OTHER:
+         scheduler = "SCHED_OTHER";
+         break;
+
+      case SCHED_FIFO:
+         scheduler = "SCHED_FIFO";
+         break;
+
+      default:
+         scheduler = "Unrelated";
+   }
+
+   RARCH_LOG("[KMS/EGL]: Current scheduler: %s\n", scheduler);
+   if (sched == SCHED_FIFO)
+      RARCH_LOG("[KMS/EGL]: SCHED_FIFO prio: %d\n", param.sched_priority);
+}
+
 bool gfx_ctx_init(void)
 {
    if (g_inited)
@@ -244,6 +277,8 @@ bool gfx_ctx_init(void)
       return false;
    }
 
+   reschedule_process();
+
    static const char *modules[] = {
       "i915", "radeon", "nouveau", "vmwgfx", "omapdrm", "exynos", NULL
    };