Improve ethread atomics

The ethread atomics API now also provide double word size atomics.
Double word size atomics are implemented using native atomic
instructions on x86 (when the cmpxchg8b instruction is available)
and on x86_64 (when the cmpxchg16b instruction is available). On
other hardware where 32-bit atomics or word size atomics are
available, an optimized fallback is used; otherwise, a spinlock,
or a mutex based fallback is used.

The ethread library now performs runtime tests for presence of
hardware features, such as for example SSE2 instructions, instead
of requiring this to be determined at compile time.

There are now functions implementing each atomic operation with the
following implied memory barrier semantics: none, read, write,
acquire, release, and full. Some of the operation-barrier
combinations aren't especially useful. But instead of filtering
useful ones out, and potentially miss a useful one, we implement
them all.

A much smaller set of functionality for native atomics are required
to be implemented than before. More or less only cmpxchg and a
membar macro are required to be implemented for each atomic size.
Other functions will automatically be constructed from these. It is,
of course, often wise to implement more that this if possible from a
performance perspective.

1 files changed, 38 insertions, 98 deletions

diff --git a/erts/include/internal/tile/atomic.h b/erts/include/internal/tile/atomic.h
index 5697afda25..1f1553c346 100644
--- a/erts/include/internal/tile/atomic.h
+++ b/erts/include/internal/tile/atomic.h
@@ -25,6 +25,7 @@
 #define ETHREAD_TILE_ATOMIC_H
 
 #define ETHR_HAVE_NATIVE_ATOMIC32 1
+#define ETHR_NATIVE_ATOMIC32_IMPL "tilera"
 
 #include <atomic.h>
 
@@ -34,27 +35,25 @@ typedef struct {
     volatile ethr_sint32_t counter;
 } ethr_native_atomic32_t;
 
-#define ETHR_MEMORY_BARRIER __insn_mf()
-
 #if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_ATOMIC_IMPL__)
 
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_ADDR 1
+
 static ETHR_INLINE ethr_sint32_t *
 ethr_native_atomic32_addr(ethr_native_atomic32_t *var)
 {
     return (ethr_sint32_t *) &var->counter;
 }
 
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_INIT 1
+
 static ETHR_INLINE void
 ethr_native_atomic32_init(ethr_native_atomic32_t *var, ethr_sint32_t i)
 {
     var->counter = i;
 }
 
-static ETHR_INLINE void
-ethr_native_atomic32_set(ethr_native_atomic32_t *var, ethr_sint32_t i)
-{
-    atomic_exchange_acq(&var->counter, i);
-}
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_READ 1
 
 static ETHR_INLINE ethr_sint32_t
 ethr_native_atomic32_read(ethr_native_atomic32_t *var)
@@ -62,139 +61,80 @@ ethr_native_atomic32_read(ethr_native_atomic32_t *var)
     return var->counter;
 }
 
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_READ_ACQB 1
+
+static ETHR_INLINE ethr_sint32_t
+ethr_native_atomic32_read_acqb(ethr_native_atomic32_t *var)
+{
+    return atomic_compare_and_exchange_val_acq(&var->counter,
+					       0x81818181,
+					       0x81818181);
+}
+
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_ADD 1
+
 static ETHR_INLINE void
 ethr_native_atomic32_add(ethr_native_atomic32_t *var, ethr_sint32_t incr)
 {
-    ETHR_MEMORY_BARRIER;
     atomic_add(&var->counter, incr);
-    ETHR_MEMORY_BARRIER;
-}      
-       
+}
+
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_INC 1
+
 static ETHR_INLINE void
 ethr_native_atomic32_inc(ethr_native_atomic32_t *var)
 {
-    ETHR_MEMORY_BARRIER;
     atomic_increment(&var->counter);
-    ETHR_MEMORY_BARRIER;
 }
 
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_DEC 1
+
 static ETHR_INLINE void
 ethr_native_atomic32_dec(ethr_native_atomic32_t *var)
 {
-    ETHR_MEMORY_BARRIER;
     atomic_decrement(&var->counter);
-    ETHR_MEMORY_BARRIER;
 }
 
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_ADD_RETURN 1
+
 static ETHR_INLINE ethr_sint32_t
 ethr_native_atomic32_add_return(ethr_native_atomic32_t *var, ethr_sint32_t incr)
 {
-    ethr_sint32_t res;
-    ETHR_MEMORY_BARRIER;
-    res = atomic_exchange_and_add(&var->counter, incr) + incr;
-    ETHR_MEMORY_BARRIER;
-    return res;
+    return atomic_exchange_and_add(&var->counter, incr) + incr;
 }
 
-static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_inc_return(ethr_native_atomic32_t *var)
-{
-    return ethr_native_atomic32_add_return(var, 1);
-}
-
-static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_dec_return(ethr_native_atomic32_t *var)
-{
-    return ethr_native_atomic32_add_return(var, -1);
-}
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_AND_RETOLD 1
 
 static ETHR_INLINE ethr_sint32_t
 ethr_native_atomic32_and_retold(ethr_native_atomic32_t *var, ethr_sint32_t mask)
 {
-    ethr_sint32_t res;
-    ETHR_MEMORY_BARRIER;
-    res = atomic_and_val(&var->counter, mask);
-    ETHR_MEMORY_BARRIER;
-    return res;
+    return atomic_and_val(&var->counter, mask);
 }
 
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_OR_RETOLD 1
+
 static ETHR_INLINE ethr_sint32_t
 ethr_native_atomic32_or_retold(ethr_native_atomic32_t *var, ethr_sint32_t mask)
 {
-    ethr_sint32_t res;
-    ETHR_MEMORY_BARRIER;
-    res = atomic_or_val(&var->counter, mask);
-    ETHR_MEMORY_BARRIER;
-    return res;
+    return atomic_or_val(&var->counter, mask);
 }
 
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_XCHG_ACQB 1
+
 static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_xchg(ethr_native_atomic32_t *var, ethr_sint32_t val)
+ethr_native_atomic32_xchg_acqb(ethr_native_atomic32_t *var, ethr_sint32_t val)
 {   
-    ETHR_MEMORY_BARRIER;
     return atomic_exchange_acq(&var->counter, val);
 } 
 
-static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_cmpxchg(ethr_native_atomic32_t *var,
-			     ethr_sint32_t new,
-			     ethr_sint32_t expected)
-{
-    ETHR_MEMORY_BARRIER;
-    return atomic_compare_and_exchange_val_acq(&var->counter, new, expected);
-}
-
-/*
- * Atomic ops with at least specified barriers.
- */
-
-static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_read_acqb(ethr_native_atomic32_t *var)
-{
-    ethr_sint32_t res = ethr_native_atomic32_read(var);
-    ETHR_MEMORY_BARRIER;
-    return res;
-}
-
-static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_inc_return_acqb(ethr_native_atomic32_t *var)
-{
-    return ethr_native_atomic32_inc_return(var);
-}
-
-static ETHR_INLINE void
-ethr_native_atomic32_set_relb(ethr_native_atomic32_t *var, ethr_sint32_t val)
-{
-    ETHR_MEMORY_BARRIER;
-    ethr_native_atomic32_set(var, val);
-}
-
-static ETHR_INLINE void
-ethr_native_atomic32_dec_relb(ethr_native_atomic32_t *var)
-{
-    ethr_native_atomic32_dec(var);
-}
-
-static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_dec_return_relb(ethr_native_atomic32_t *var)
-{
-    return ethr_native_atomic32_dec_return(var);
-}
+#define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_CMPXCHG_ACQB 1
 
 static ETHR_INLINE ethr_sint32_t
 ethr_native_atomic32_cmpxchg_acqb(ethr_native_atomic32_t *var,
 				  ethr_sint32_t new,
-				  ethr_sint32_t exp)
+				  ethr_sint32_t expected)
 {
-    return ethr_native_atomic32_cmpxchg(var, new, exp);
-}
-
-static ETHR_INLINE ethr_sint32_t
-ethr_native_atomic32_cmpxchg_relb(ethr_native_atomic32_t *var,
-				  ethr_sint32_t new,
-				  ethr_sint32_t exp)
-{
-    return ethr_native_atomic32_cmpxchg(var, new, exp);
+    return atomic_compare_and_exchange_val_acq(&var->counter, new, expected);
 }
 
 #endif /* ETHR_TRY_INLINE_FUNCS */