From 5b2dc520340103491088616ba4f58095948f5821 Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Tue, 18 Jun 2013 00:17:14 -0700
Subject: [PATCH] std::rt: Turn on multithreaded scheduling

---
 src/libstd/rt/mod.rs | 92 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 76 insertions(+), 16 deletions(-)

diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
index 0a269aa8767..581e3addff0 100644
--- a/src/libstd/rt/mod.rs
+++ b/src/libstd/rt/mod.rs
@@ -60,7 +60,21 @@ Several modules in `core` are clients of `rt`:
 #[deny(unused_variable)];
 
 use cell::Cell;
+use clone::Clone;
+use container::Container;
+use from_str::FromStr;
+use iterator::IteratorUtil;
+use option::{Some, None};
+use os;
 use ptr::RawPtr;
+use uint;
+use rt::sched::{Scheduler, Coroutine, Shutdown};
+use rt::sleeper_list::SleeperList;
+use rt::task::Task;
+use rt::thread::Thread;
+use rt::work_queue::WorkQueue;
+use rt::uv::uvio::UvEventLoop;
+use vec::{OwnedVector, MutableVector};
 
 /// The global (exchange) heap.
 pub mod global_heap;
@@ -159,23 +173,8 @@ pub mod util;
 /// The return value is used as the process return code. 0 on success, 101 on error.
 pub fn start(_argc: int, _argv: **u8, crate_map: *u8, main: ~fn()) -> int {
 
-    use self::sched::{Scheduler, Coroutine};
-    use self::work_queue::WorkQueue;
-    use self::uv::uvio::UvEventLoop;
-    use self::sleeper_list::SleeperList;
-
     init(crate_map);
-
-    let loop_ = ~UvEventLoop::new();
-    let work_queue = WorkQueue::new();
-    let sleepers = SleeperList::new();
-    let mut sched = ~Scheduler::new(loop_, work_queue, sleepers);
-    sched.no_sleep = true;
-    let main_task = ~Coroutine::new_root(&mut sched.stack_pool, main);
-
-    sched.enqueue_task(main_task);
-    sched.run();
-
+    run(main);
     cleanup();
 
     return 0;
@@ -191,6 +190,67 @@ pub fn cleanup() {
     global_heap::cleanup();
 }
 
+pub fn run(main: ~fn()) {
+    let nthreads = match os::getenv("RUST_THREADS") {
+        Some(nstr) => FromStr::from_str(nstr).get(),
+        None => unsafe {
+            // Using more threads than cores in test code
+            // to force the OS to preempt them frequently.
+            // Assuming that this help stress test concurrent types.
+            util::num_cpus() * 2
+        }
+    };
+
+    let sleepers = SleeperList::new();
+    let work_queue = WorkQueue::new();
+
+    let mut handles = ~[];
+    let mut scheds = ~[];
+
+    for uint::range(0, nthreads) |_| {
+        let loop_ = ~UvEventLoop::new();
+        let mut sched = ~Scheduler::new(loop_, work_queue.clone(), sleepers.clone());
+        let handle = sched.make_handle();
+
+        handles.push(handle);
+        scheds.push(sched);
+    }
+
+    let main_cell = Cell::new(main);
+    let handles = Cell::new(handles);
+    let mut new_task = ~Task::new_root();
+    let on_exit: ~fn(bool) = |exit_status| {
+
+        let mut handles = handles.take();
+        // Tell schedulers to exit
+        for handles.mut_iter().advance |handle| {
+            handle.send(Shutdown);
+        }
+
+        rtassert!(exit_status);
+    };
+    new_task.on_exit = Some(on_exit);
+    let main_task = ~Coroutine::with_task(&mut scheds[0].stack_pool,
+                                          new_task, main_cell.take());
+    scheds[0].enqueue_task(main_task);
+
+    let mut threads = ~[];
+
+    while !scheds.is_empty() {
+        let sched = scheds.pop();
+        let sched_cell = Cell::new(sched);
+        let thread = do Thread::start {
+            let sched = sched_cell.take();
+            sched.run();
+        };
+
+        threads.push(thread);
+    }
+
+    // Wait for schedulers
+    let _threads = threads;
+}
+
 /// Possible contexts in which Rust code may be executing.
 /// Different runtime services are available depending on context.
 /// Mostly used for determining if we're using the new scheduler