Changeset 7a2972b for libcfa/src/concurrency/ready_queue.cfa

Timestamp:

Apr 1, 2021, 9:02:57 PM (2 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

7ee3c87

Parents:

c426b03

Message:

ready queue can now toggle between

• lock-based queue
• mpsc_queue a.k.a. nemesis queue

slightly messy implementation, some clean up needed.

File:

• libcfa/src/concurrency/ready_queue.cfa (modified) (6 diffs)

libcfa/src/concurrency/ready_queue.cfa

@@ -18 +18 @@
 
 // #define USE_SNZI
+// #define USE_MPSC
 
 #include "bits/defs.hfa"
@@ -284 +285 @@
                 #endif
 
+        #if defined(USE_MPSC)
+                // mpsc always succeeds
+        } while( false );
+        #else
                 // If we can't lock it retry
         } while( !__atomic_try_acquire( &lanes.data[i].lock ) );
+        #endif
 
         // Actually push it
@@ -305 +311 @@
         #endif
 
-        // Unlock and return
-        __atomic_unlock( &lanes.data[i].lock );
+        #if !defined(USE_MPSC)
+                // Unlock and return
+                __atomic_unlock( &lanes.data[i].lock );
+        #endif
 
         // Mark the current index in the tls rng instance as having an item
@@ -493 +501 @@
 
 static void check( __ready_queue_t & q ) with (q) {
-        #if defined(__CFA_WITH_VERIFY__)
+        #if defined(__CFA_WITH_VERIFY__) && !defined(USE_MPSC)
                 {
                         for( idx ; lanes.count ) {
@@ -504 +512 @@
                                 assert(tail(sl)->link.prev->link.next == tail(sl) );
 
-                                if(sl.before.link.ts == 0l) {
+                                if(is_empty(sl)) {
                                         assert(tail(sl)->link.prev == head(sl));
                                         assert(head(sl)->link.next == tail(sl));
@@ -519 +527 @@
 // fixes the list so that the pointers back to anchors aren't left dangling
 static inline void fix(__intrusive_lane_t & ll) {
-        // if the list is not empty then follow he pointer and fix its reverse
-        if(!is_empty(ll)) {
-                head(ll)->link.next->link.prev = head(ll);
-                tail(ll)->link.prev->link.next = tail(ll);
-        }
-        // Otherwise just reset the list
-        else {
-                verify(tail(ll)->link.next == 0p);
-                tail(ll)->link.prev = head(ll);
-                head(ll)->link.next = tail(ll);
-                verify(head(ll)->link.prev == 0p);
-        }
+        #if !defined(USE_MPSC)
+                // if the list is not empty then follow he pointer and fix its reverse
+                if(!is_empty(ll)) {
+                        head(ll)->link.next->link.prev = head(ll);
+                        tail(ll)->link.prev->link.next = tail(ll);
+                }
+                // Otherwise just reset the list
+                else {
+                        verify(tail(ll)->link.next == 0p);
+                        tail(ll)->link.prev = head(ll);
+                        head(ll)->link.next = tail(ll);
+                        verify(head(ll)->link.prev == 0p);
+                }
+        #endif
 }