edits

[cdsspec-compiler.git] / benchmark / mcs-lock / mcs-lock.h

diff --git a/benchmark/mcs-lock/mcs-lock.h b/benchmark/mcs-lock/mcs-lock.h
index 8ff58a23e3d459f7ea43d26158b33974f5775b75..9f4781246e0e2c0cea2c308e2cbc409f9cc281fb 100644 (file)
--- a/benchmark/mcs-lock/mcs-lock.h
+++ b/benchmark/mcs-lock/mcs-lock.h
@@ -3,8 +3,12 @@
 #include <stdatomic.h>
 #include <unrelacy.h>
 
-
-
+#include <spec_lib.h>
+#include <stdlib.h>
+#include <cdsannotate.h>
+#include <specannotation.h>
+#include <model_memory.h>
+#include "common.h" 
 
 struct mcs_node {
        std::atomic<mcs_node *> next;
@@ -31,7 +35,7 @@ public:
                m_tail.store( NULL );
        }
        ~mcs_mutex() {
-               ASSERT( m_tail.load() == NULL );
+               //ASSERT( m_tail.load() == NULL );
        }
 
        // Each thread will have their own guard.
@@ -50,12 +54,9 @@ public:
                        LANG = CPP;
                        CLASS = mcs_mutex;
                @Global_define:
-                       @DeclareVar:
-                               bool _lock_acquired;
-                       @InitVar:
-                               _lock_acquired = false;
-               @Happens_before:
-                       Unlock -> Lock
+                       @DeclareVar: bool _lock_acquired;
+                       @InitVar: _lock_acquired = false;
+               @Happens_before: Unlock -> Lock
                @End
        */
 
@@ -63,10 +64,8 @@ public:
                @Begin
                @Interface: Lock
                @Commit_point_set: Lock_Enqueue_Point1 | Lock_Enqueue_Point2
-               @Check:
-                       _lock_acquired == false;
-               @Action:
-                       _lock_acquired = true;
+               @Check: _lock_acquired == false;
+               @Action: _lock_acquired = true;
                @End
        */
        void lock(guard * I) {
@@ -77,6 +76,8 @@ public:
                me->next.store(NULL, std::mo_relaxed );
                me->gate.store(1, std::mo_relaxed );
 
+               /**********  Inadmissible  **********/
+               /** Run this in the -Y mode to expose the HB bug */
                // publish my node as the new tail :
                mcs_node * pred = m_tail.exchange(me, std::mo_acq_rel);
                /**
@@ -90,7 +91,11 @@ public:
                        // unlock of pred can see me in the tail before I fill next
 
                        // publish me to previous lock-holder :
+                       // FIXME: detection miss, execution never ends
+                       // If this is relaxed, the store 0 to gate will be read before and
+                       // that lock will never ends.
                        pred->next.store(me, std::mo_release );
+                       //printf("lock_miss1\n");
 
                        // (*2) pred not touched any more       
 
@@ -99,7 +104,10 @@ public:
                        rl::linear_backoff bo;
                        int my_gate = 1;
                        while (my_gate ) {
+                               /**********  Inadmissibility  *********/
                                my_gate = me->gate.load(std::mo_acquire);
+                               //if (my_gate == 0)
+                                       //printf("lock at gate!\n");
                                /**
                                        @Begin
                                        @Commit_point_define_check: my_gate == 0
@@ -114,22 +122,23 @@ public:
        /**
                @Begin
                @Interface: Unlock
-               @Commit_point_set:
-                       Unlock_Point_Success_1 | Unlock_Point_Success_2
-               @Check:
-                       _lock_acquired == true
-               @Action:
-                       _lock_acquired = false;
+               @Commit_point_set: Unlock_Point_Success_1 | Unlock_Point_Success_2
+               @Check: _lock_acquired == true
+               @Action: _lock_acquired = false;
                @End
        */
        void unlock(guard * I) {
                mcs_node * me = &(I->m_node);
 
+               // FIXME: detection miss, execution never ends
                mcs_node * next = me->next.load(std::mo_acquire);
+               //printf("unlock_miss2\n");
                if ( next == NULL )
                {
                        mcs_node * tail_was_me = me;
                        bool success;
+
+                       /**********  Inadmissible  **********/
                        success = m_tail.compare_exchange_strong(
                                tail_was_me,NULL,std::mo_acq_rel);
                        /**
@@ -147,7 +156,9 @@ public:
                        // (*1) catch the race :
                        rl::linear_backoff bo;
                        for(;;) {
+                               // FIXME: detection miss, execution never ends
                                next = me->next.load(std::mo_acquire);
+                               //printf("unlock_miss3\n");
                                if ( next != NULL )
                                        break;
                                thrd_yield();
@@ -157,6 +168,7 @@ public:
                // (*2) - store to next must be done,
                //  so no locker can be viewing my node any more        
 
+               /**********  Inadmissible  **********/
                // let next guy in :
                next->gate.store( 0, std::mo_release );
                /**