Added support for adjusting thread priorities using Linux RealtimeKit

Michael Sartain

This is a quick pass at adding Linux RealtimeKit thread priority support to SDL.

It allows me to bump the thread priority to high without root privileges or setting any caps, etc.

rtkit readme here:
    http://git.0pointer.net/rtkit.git/tree/README

1 files changed, 31 insertions, 0 deletions

diff --git a/test/testthread.c b/test/testthread.c
index cdccfc499..efba681e8 100644
--- a/test/testthread.c
+++ b/test/testthread.c
@@ -20,6 +20,7 @@
 
 static SDL_TLSID tls;
 static int alive = 0;
+static int testprio = 0;
 
 /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
 static void
@@ -29,14 +30,36 @@ quit(int rc)
     exit(rc);
 }
 
+static const char *
+getprioritystr(SDL_ThreadPriority priority)
+{
+    switch(priority)
+    {
+    case SDL_THREAD_PRIORITY_LOW: return "SDL_THREAD_PRIORITY_LOW";
+    case SDL_THREAD_PRIORITY_NORMAL: return "SDL_THREAD_PRIORITY_NORMAL";
+    case SDL_THREAD_PRIORITY_HIGH: return "SDL_THREAD_PRIORITY_HIGH";
+    }
+
+    return "???";
+}
+
 int SDLCALL
 ThreadFunc(void *data)
 {
+    SDL_ThreadPriority prio = SDL_THREAD_PRIORITY_NORMAL;
+
     SDL_TLSSet(tls, "baby thread", NULL);
     SDL_Log("Started thread %s: My thread id is %lu, thread data = %s\n",
            (char *) data, SDL_ThreadID(), (const char *)SDL_TLSGet(tls));
     while (alive) {
         SDL_Log("Thread '%s' is alive!\n", (char *) data);
+
+        if (testprio) {
+            SDL_Log("SDL_SetThreadPriority(%s):%d\n", getprioritystr(prio), SDL_SetThreadPriority(prio));
+            if (++prio > SDL_THREAD_PRIORITY_HIGH)
+                prio = SDL_THREAD_PRIORITY_LOW;
+        }
+
         SDL_Delay(1 * 1000);
     }
     SDL_Log("Thread '%s' exiting!\n", (char *) data);
@@ -55,6 +78,7 @@ killed(int sig)
 int
 main(int argc, char *argv[])
 {
+    int arg = 1;
     SDL_Thread *thread;
 
     /* Enable standard application logging */
@@ -66,6 +90,13 @@ main(int argc, char *argv[])
         return (1);
     }
 
+    while (argv[arg] && *argv[arg] == '-') {
+        if (SDL_strcmp(argv[arg], "--prio") == 0) {
+            testprio = 1;
+        }
+        ++arg;
+    }
+
     tls = SDL_TLSCreate();
     SDL_assert(tls);
     SDL_TLSSet(tls, "main thread", NULL);