Changeset f2384c9a for libcfa/src/concurrency/kernel

Timestamp:

Aug 18, 2020, 1:58:59 PM (4 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

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

Children:

133a161, 13d33a75

Parents:

93526ef

Message:

Added forward/reverse rng for later use in the ready queue

Location:

libcfa/src/concurrency/kernel

Files:

• fwd.hfa (modified) (2 diffs)
• startup.cfa (modified) (3 diffs)

libcfa/src/concurrency/kernel/fwd.hfa

@@ -50 +50 @@
                                 uint64_t rand_seed;
                         #endif
+                        struct {
+                                uint64_t fwd_seed;
+                                uint64_t bck_seed;
+                        } ready_rng;
                 } kernelTLS __attribute__ ((tls_model ( "initial-exec" )));
+
+
 
                 static inline uint64_t __tls_rand() {
@@ -58 +64 @@
                                 return __xorshift64( kernelTLS.rand_seed );
                         #endif
+                }
+
+                #define M  (1_l64u << 48_l64u)
+                #define A  (25214903917_l64u)
+                #define AI (18446708753438544741_l64u)
+                #define C  (11_l64u)
+                #define D  (16_l64u)
+
+                static inline unsigned __tls_rand_fwd() {
+
+                        kernelTLS.ready_rng.fwd_seed = (A * kernelTLS.ready_rng.fwd_seed + C) & (M - 1);
+                        return kernelTLS.ready_rng.fwd_seed >> D;
+                }
+
+                static inline unsigned __tls_rand_bck() {
+                        unsigned int r = kernelTLS.ready_rng.bck_seed >> D;
+                        kernelTLS.ready_rng.bck_seed = AI * (kernelTLS.ready_rng.bck_seed - C) & (M - 1);
+                        return r;
+                }
+
+                #undef M
+                #undef A
+                #undef AI
+                #undef C
+                #undef D
+
+                static inline void __tls_rand_advance_bck(void) {
+                        kernelTLS.ready_rng.bck_seed = kernelTLS.ready_rng.fwd_seed;
                 }
         }

libcfa/src/concurrency/kernel/startup.cfa

@@ -78 +78 @@
 static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info);
 
+#if defined(__CFA_WITH_VERIFY__)
+        static bool verify_fwd_bck_rng(void);
+#endif
+
 //-----------------------------------------------------------------------------
 // Forward Declarations for other modules
@@ -158 +162 @@
         __cfa_dbg_global_clusters.list{ __get };
         __cfa_dbg_global_clusters.lock{};
+
+        /* paranoid */ verify( verify_fwd_bck_rng() );
 
         // Initialize the global scheduler lock
@@ -677 +683 @@
         return stack;
 }
+
+#if defined(__CFA_WITH_VERIFY__)
+static bool verify_fwd_bck_rng(void) {
+        kernelTLS.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&verify_fwd_bck_rng);
+
+        unsigned values[10];
+        for(i; 10) {
+                values[i] = __tls_rand_fwd();
+        }
+
+        __tls_rand_advance_bck();
+
+        for ( i; 9 -~= 0 ) {
+                if(values[i] != __tls_rand_bck()) {
+                        return false;
+                }
+        }
+
+        return true;
+}
+#endif