Changeset 37b2c2c

Timestamp:

Jun 9, 2023, 2:31:04 PM (18 months ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

ast-experimental, master

Children:

758c9ef

Parents:

0442f93f

Message:

update lockfree stack with double-wide CAS

File:

• tests/concurrency/lockfree_stack.cfa (modified) (6 diffs)

tests/concurrency/lockfree_stack.cfa

@@ -10 +10 @@
 // Created On       : Thu May 25 15:36:50 2023
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Tue May 30 19:02:32 2023
-// Update Count     : 18
+// Last Modified On : Fri Jun  9 14:01:07 2023
+// Update Count     : 68
 // 
 
@@ -29 +29 @@
         int64_t atom;
         #endif // __SIZEOF_INT128__
-} __attribute__(( aligned( 16 ) ));
+};
 
 struct Node {
@@ -42 +42 @@
         n.next = stack;                                                                         // atomic assignment unnecessary
         for () {                                                                                        // busy wait
-                if ( CASV( stack.atom, n.next.atom, ((Link){ &n, n.next.count + 1 }.atom) ) ) break; // attempt to update top node
+                Link temp{ &n, n.next.count + 1 };
+                if ( CASV( s.stack.atom, n.next.atom, temp.atom ) ) break; // attempt to update top node
         }
 }
@@ -50 +51 @@
         for () {                                                                                        // busy wait
                 if ( t.top == NULL ) return NULL;                               // empty stack ?
-                if ( CASV( stack.atom, t.atom, ((Link){ t.top->next.top, t.count }.atom) ) ) return t.top; // attempt to update top node
+                Link temp{ t.top->next.top, t.count };
+                if ( CASV( stack.atom, t.atom, temp.atom ) ) return t.top; // attempt to update top node
         }
 }
@@ -57 +59 @@
 Stack stack;                                                                                    // global stack
 
-enum { Times =
-        #if defined( __ARM_ARCH )                                                       // ARM CASV is very slow
-        10_000
-        #else
-        1_000_000
-        #endif // __arm_64__
-};
+enum { Times = 2_000_000 };
 
 thread Worker {};
@@ -82 +78 @@
 
         for ( i; N ) {                                                                          // push N values on stack
-                // storage must be 16-bytes aligned for cmpxchg16b
-                push( stack, *(Node *)memalign( 16, sizeof( Node ) ) );
+                push( stack, *(Node *)new() );                                  // must be 16-byte aligned
         }
         {