From 8aee42a382eff8fc35d1341be5b307da87a25603 Mon Sep 17 00:00:00 2001
From: Jon Morton <jonanin@gmail.com>
Date: Sat, 31 Mar 2012 01:57:29 -0500
Subject: [PATCH 1/2] Choose task thread in rust_scheduler by round robin

Remove the random context from rust_scheduler and use a simple round robin system to choose which thread a new task gets put on. Also, some incorrect tab indents around scoped blocks were fixed.
---
 src/rt/rust_scheduler.cpp | 25 +++++++++++++------------
 src/rt/rust_scheduler.h   |  4 ++--
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/rt/rust_scheduler.cpp b/src/rt/rust_scheduler.cpp
index 8daee5626477a..8b50cfa87d2b2 100644
--- a/src/rt/rust_scheduler.cpp
+++ b/src/rt/rust_scheduler.cpp
@@ -13,7 +13,6 @@ rust_scheduler::rust_scheduler(rust_kernel *kernel,
     num_threads(num_threads),
     id(id)
 {
-    isaac_init(kernel, &rctx);
     create_task_threads();
 }
 
@@ -86,9 +85,11 @@ rust_task *
 rust_scheduler::create_task(rust_task *spawner, const char *name) {
     size_t thread_no;
     {
-	scoped_lock with(lock);
-	thread_no = isaac_rand(&rctx) % num_threads;
-	live_tasks++;
+        scoped_lock with(lock);
+        live_tasks++;
+        if (++cur_thread >= num_threads)
+            cur_thread = 0;
+        thread_no = cur_thread;
     }
     rust_task_thread *thread = threads[thread_no];
     return thread->create_task(spawner, name);
@@ -98,11 +99,11 @@ void
 rust_scheduler::release_task() {
     bool need_exit = false;
     {
-	scoped_lock with(lock);
-	live_tasks--;
-	if (live_tasks == 0) {
-	    need_exit = true;
-	}
+        scoped_lock with(lock);
+        live_tasks--;
+        if (live_tasks == 0) {
+            need_exit = true;
+        }
     }
     if (need_exit) {
 	// There are no more tasks on this scheduler. Time to leave
@@ -129,10 +130,10 @@ void
 rust_scheduler::release_task_thread() {
     uintptr_t new_live_threads;
     {
-	scoped_lock with(lock);
-	new_live_threads = --live_threads;
+        scoped_lock with(lock);
+        new_live_threads = --live_threads;
     }
     if (new_live_threads == 0) {
-	kernel->release_scheduler_id(id);
+        kernel->release_scheduler_id(id);
     }
 }
diff --git a/src/rt/rust_scheduler.h b/src/rt/rust_scheduler.h
index ad188b79126e1..dae867536fb3b 100644
--- a/src/rt/rust_scheduler.h
+++ b/src/rt/rust_scheduler.h
@@ -10,16 +10,16 @@ class rust_scheduler : public kernel_owned<rust_scheduler> {
     rust_srv *srv;
     rust_env *env;
 private:
-    // Protects the random number context and live_threads
+    // Protects live_threads and cur_thread increments
     lock_and_signal lock;
     // When this hits zero we'll tell the kernel to release us
     uintptr_t live_threads;
     // When this hits zero we'll tell the threads to exit
     uintptr_t live_tasks;
-    randctx rctx;
 
     array_list<rust_task_thread *> threads;
     const size_t num_threads;
+    size_t cur_thread;
 
     rust_sched_id id;
 

From 9851a906a59faee4ca13a8cf76677287793809a2 Mon Sep 17 00:00:00 2001
From: Jon Morton <jonanin@gmail.com>
Date: Sat, 31 Mar 2012 13:14:54 -0500
Subject: [PATCH 2/2] initialize cur_thread, first task on thread 0

---
 src/rt/rust_scheduler.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/rt/rust_scheduler.cpp b/src/rt/rust_scheduler.cpp
index 8b50cfa87d2b2..482739ded99be 100644
--- a/src/rt/rust_scheduler.cpp
+++ b/src/rt/rust_scheduler.cpp
@@ -11,6 +11,7 @@ rust_scheduler::rust_scheduler(rust_kernel *kernel,
     live_threads(num_threads),
     live_tasks(0),
     num_threads(num_threads),
+    cur_thread(0),
     id(id)
 {
     create_task_threads();
@@ -87,9 +88,9 @@ rust_scheduler::create_task(rust_task *spawner, const char *name) {
     {
         scoped_lock with(lock);
         live_tasks++;
-        if (++cur_thread >= num_threads)
+        thread_no = cur_thread++;
+        if (cur_thread >= num_threads)
             cur_thread = 0;
-        thread_no = cur_thread;
     }
     rust_task_thread *thread = threads[thread_no];
     return thread->create_task(spawner, name);