Tidy up the sync dir, remove dead or mis-designed code in favour of OS primitives, switch rust_kernel to use a lock/signal pair and wait rather than spin.

1 files changed, 0 insertions, 43 deletions

diff --git a/src/rt/sync/fair_ticket_lock.cpp b/src/rt/sync/fair_ticket_lock.cpp
deleted file mode 100644
index 0306ee1df39..00000000000
--- a/src/rt/sync/fair_ticket_lock.cpp
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * This works well as long as the number of contending threads
- * is less than the number of processors. This is because of
- * the fair locking scheme. If the thread that is next in line
- * for acquiring the lock is not currently running, no other
- * thread can acquire the lock. This is terrible for performance,
- * and it seems that all fair locking schemes suffer from this
- * behavior.
- */
-
-// #define TRACE
-
-fair_ticket_lock::fair_ticket_lock() {
-    next_ticket = now_serving = 0;
-}
-
-fair_ticket_lock::~fair_ticket_lock() {
-
-}
-
-void fair_ticket_lock::lock() {
-    unsigned ticket = __sync_fetch_and_add(&next_ticket, 1);
-    while (now_serving != ticket) {
-        pause();
-    }
-#ifdef TRACE
-    printf("locked   nextTicket: %d nowServing: %d",
-            next_ticket, now_serving);
-#endif
-}
-
-void fair_ticket_lock::unlock() {
-    now_serving++;
-#ifdef TRACE
-    printf("unlocked nextTicket: %d nowServing: %d",
-            next_ticket, now_serving);
-#endif
-}
-
-void fair_ticket_lock::pause() {
-    asm volatile("pause\n" : : : "memory");
-}
-