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, 151 insertions, 183 deletions

diff --git a/erts/include/internal/i386/atomic.h b/erts/include/internal/i386/atomic.h
index 4e402f261a..fc1b619935 100644
--- a/erts/include/internal/i386/atomic.h
+++ b/erts/include/internal/i386/atomic.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2005-2010. All Rights Reserved.
+ * Copyright Ericsson AB 2005-2011. All Rights Reserved.
  *
  * The contents of this file are subject to the Erlang Public License,
  * Version 1.1, (the "License"); you may not use this file except in
@@ -25,53 +25,42 @@
  */
 
 #undef ETHR_INCLUDE_ATOMIC_IMPL__
-#if !defined(ETHR_X86_ATOMIC32_H__) && defined(ETHR_ATOMIC_WANT_32BIT_IMPL__)
-#define ETHR_X86_ATOMIC32_H__
-#define ETHR_INCLUDE_ATOMIC_IMPL__ 4
-#undef ETHR_ATOMIC_WANT_32BIT_IMPL__
-#elif !defined(ETHR_X86_ATOMIC64_H__) && defined(ETHR_ATOMIC_WANT_64BIT_IMPL__)
-#define ETHR_X86_ATOMIC64_H__
-#define ETHR_INCLUDE_ATOMIC_IMPL__ 8
-#undef ETHR_ATOMIC_WANT_64BIT_IMPL__
+#if !defined(ETHR_X86_ATOMIC32_H__) \
+    && defined(ETHR_ATOMIC_WANT_32BIT_IMPL__)
+#  define ETHR_X86_ATOMIC32_H__
+#  define ETHR_INCLUDE_ATOMIC_IMPL__ 4
+#  undef ETHR_ATOMIC_WANT_32BIT_IMPL__
+#elif !defined(ETHR_X86_ATOMIC64_H__) \
+      && defined(ETHR_ATOMIC_WANT_64BIT_IMPL__)
+#  define ETHR_X86_ATOMIC64_H__
+#  define ETHR_INCLUDE_ATOMIC_IMPL__ 8
+#  undef ETHR_ATOMIC_WANT_64BIT_IMPL__
 #endif
 
 #ifdef ETHR_INCLUDE_ATOMIC_IMPL__
 
-#ifndef ETHR_X86_ATOMIC_COMMON__
-#define ETHR_X86_ATOMIC_COMMON__
-
-#define ETHR_ATOMIC_HAVE_INC_DEC_INSTRUCTIONS 1
-
-#if defined(__x86_64__) || !defined(ETHR_PRE_PENTIUM4_COMPAT)
-#define ETHR_MEMORY_BARRIER __asm__ __volatile__("mfence" : : : "memory")
-#define ETHR_WRITE_MEMORY_BARRIER __asm__ __volatile__("sfence" : : : "memory")
-#define ETHR_READ_MEMORY_BARRIER __asm__ __volatile__("lfence" : : : "memory")
-#define ETHR_READ_DEPEND_MEMORY_BARRIER __asm__ __volatile__("" : : : "memory")
-#else
-#define ETHR_MEMORY_BARRIER \
-do { \
-    volatile ethr_sint32_t x___ = 0; \
-    __asm__ __volatile__("lock; incl %0" : "=m"(x___) : "m"(x___) : "memory"); \
-} while (0)
-#endif
-
-#endif /* ETHR_X86_ATOMIC_COMMON__ */
-
-#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
-#define ETHR_HAVE_NATIVE_ATOMIC32 1
-#define ETHR_NATMC_FUNC__(X) ethr_native_atomic32_ ## X
-#define ETHR_ATMC_T__ ethr_native_atomic32_t
-#define ETHR_AINT_T__ ethr_sint32_t
-#define ETHR_AINT_SUFFIX__ "l"
-#elif ETHR_INCLUDE_ATOMIC_IMPL__ == 8
-#define ETHR_HAVE_NATIVE_ATOMIC64 1
-#define ETHR_NATMC_FUNC__(X) ethr_native_atomic64_ ## X
-#define ETHR_ATMC_T__ ethr_native_atomic64_t
-#define ETHR_AINT_T__ ethr_sint64_t
-#define ETHR_AINT_SUFFIX__ "q"
-#else
-#error "Unsupported integer size"
-#endif
+#  ifndef ETHR_X86_ATOMIC_COMMON__
+#    define ETHR_X86_ATOMIC_COMMON__
+#    define ETHR_ATOMIC_HAVE_INC_DEC_INSTRUCTIONS 1
+#  endif /* ETHR_X86_ATOMIC_COMMON__ */
+
+#  if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#    define ETHR_HAVE_NATIVE_ATOMIC32 1
+#    define ETHR_NATIVE_ATOMIC32_IMPL "ethread"
+#    define ETHR_NATMC_FUNC__(X) ethr_native_atomic32_ ## X
+#    define ETHR_ATMC_T__ ethr_native_atomic32_t
+#    define ETHR_AINT_T__ ethr_sint32_t
+#    define ETHR_AINT_SUFFIX__ "l"
+#  elif ETHR_INCLUDE_ATOMIC_IMPL__ == 8
+#    define ETHR_HAVE_NATIVE_ATOMIC64 1
+#    define ETHR_NATIVE_ATOMIC64_IMPL "ethread"
+#    define ETHR_NATMC_FUNC__(X) ethr_native_atomic64_ ## X
+#    define ETHR_ATMC_T__ ethr_native_atomic64_t
+#    define ETHR_AINT_T__ ethr_sint64_t
+#    define ETHR_AINT_SUFFIX__ "q"
+#  else
+#    error "Unsupported integer size"
+#  endif
 
 /* An atomic is an aligned ETHR_AINT_T__ accessed via locked operations.
  */
@@ -81,87 +70,28 @@ typedef struct {
 
 #if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_ATOMIC_IMPL__)
 
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_ADDR 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_ADDR 1
+#endif
+
 static ETHR_INLINE ETHR_AINT_T__ *
 ETHR_NATMC_FUNC__(addr)(ETHR_ATMC_T__ *var)
 {
     return (ETHR_AINT_T__ *) &var->counter;
 }
 
-static ETHR_INLINE void
-ETHR_NATMC_FUNC__(init)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ i)
-{
-    var->counter = i;
-}
-
-static ETHR_INLINE void
-ETHR_NATMC_FUNC__(set)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ i)
-{
-    var->counter = i;
-}
-
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(read)(ETHR_ATMC_T__ *var)
-{
-    return var->counter;
-}
-
-static ETHR_INLINE void
-ETHR_NATMC_FUNC__(add)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ incr)
-{
-    __asm__ __volatile__(
-       "lock; add" ETHR_AINT_SUFFIX__ " %1, %0"
-       : "=m"(var->counter)
-       : "ir"(incr), "m"(var->counter));
-}      
-       
-static ETHR_INLINE void
-ETHR_NATMC_FUNC__(inc)(ETHR_ATMC_T__ *var)
-{
-    __asm__ __volatile__(
-	"lock; inc" ETHR_AINT_SUFFIX__ " %0"
-	: "=m"(var->counter)
-	: "m"(var->counter));
-}
-
-static ETHR_INLINE void
-ETHR_NATMC_FUNC__(dec)(ETHR_ATMC_T__ *var)
-{
-    __asm__ __volatile__(
-	"lock; dec" ETHR_AINT_SUFFIX__ " %0"
-	: "=m"(var->counter)
-	: "m"(var->counter));
-}
-
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(add_return)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ incr)
-{
-    ETHR_AINT_T__ tmp;
-
-    tmp = incr;
-    __asm__ __volatile__(
-	"lock; xadd" ETHR_AINT_SUFFIX__ " %0, %1" /* xadd didn't exist prior to the 486 */
-	: "=r"(tmp)
-	: "m"(var->counter), "0"(tmp));
-    /* now tmp is the atomic's previous value */
-    return tmp + incr;
-}
-
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(inc_return)(ETHR_ATMC_T__ *var)
-{
-    return ETHR_NATMC_FUNC__(add_return)(var, (ETHR_AINT_T__) 1);
-}
-
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(dec_return)(ETHR_ATMC_T__ *var)
-{
-    return ETHR_NATMC_FUNC__(add_return)(var, (ETHR_AINT_T__) -1);
-}
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_CMPXCHG_MB 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_CMPXCHG_MB 1
+#endif
 
 static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(cmpxchg)(ETHR_ATMC_T__ *var,
-			   ETHR_AINT_T__ new,
-			   ETHR_AINT_T__ old)
+ETHR_NATMC_FUNC__(cmpxchg_mb)(ETHR_ATMC_T__ *var,
+			      ETHR_AINT_T__ new,
+			      ETHR_AINT_T__ old)
 {
     __asm__ __volatile__(
       "lock; cmpxchg" ETHR_AINT_SUFFIX__ " %2, %3"
@@ -171,110 +101,148 @@ ETHR_NATMC_FUNC__(cmpxchg)(ETHR_ATMC_T__ *var,
     return old;
 }
 
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(and_retold)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ mask)
-{
-    ETHR_AINT_T__ tmp, old;
-
-    tmp = var->counter;
-    do {
-	old = tmp;
-        tmp = ETHR_NATMC_FUNC__(cmpxchg)(var, tmp & mask, tmp);
-    } while (__builtin_expect(tmp != old, 0));
-    /* now tmp is the atomic's previous value */
-    return tmp;
-}
-
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(or_retold)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ mask)
-{
-    ETHR_AINT_T__ tmp, old;
-
-    tmp = var->counter;
-    do {
-	old = tmp;
-        tmp = ETHR_NATMC_FUNC__(cmpxchg)(var, tmp | mask, tmp);
-    } while (__builtin_expect(tmp != old, 0));
-    /* now tmp is the atomic's previous value */
-    return tmp;
-}
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_XCHG_MB 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_XCHG_MB 1
+#endif
 
 static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(xchg)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ val)
+ETHR_NATMC_FUNC__(xchg_mb)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ val)
 {   
     ETHR_AINT_T__ tmp = val;
     __asm__ __volatile__(
 	"xchg" ETHR_AINT_SUFFIX__ " %0, %1"
 	: "=r"(tmp)
-	: "m"(var->counter), "0"(tmp));
+	: "m"(var->counter), "0"(tmp)
+	: "memory");
     /* now tmp is the atomic's previous value */ 
     return tmp;
 } 
 
-/*
- * Atomic ops with at least specified barriers.
- */
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_SET 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_SET 1
+#endif
 
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(read_acqb)(ETHR_ATMC_T__ *var)
+static ETHR_INLINE void
+ETHR_NATMC_FUNC__(set)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ i)
 {
-    ETHR_AINT_T__ val;
-#if defined(__x86_64__) || !defined(ETHR_PRE_PENTIUM4_COMPAT)
-    val = var->counter;
+    var->counter = i;
+}
+
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_SET_RELB 1
 #else
-    val = ETHR_NATMC_FUNC__(add_return)(var, 0);
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_SET_RELB 1
 #endif
-    __asm__ __volatile__("" : : : "memory");
-    return val;
-}
 
 static ETHR_INLINE void
 ETHR_NATMC_FUNC__(set_relb)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ i)
 {
-    __asm__ __volatile__("" : : : "memory");
-#if defined(__x86_64__) || !defined(ETHR_PRE_PENTIUM4_COMPAT)
-    var->counter = i;
+#if defined(_M_IX86)
+    if (ETHR_X86_RUNTIME_CONF_HAVE_NO_SSE2__)
+	(void) ETHR_NATMC_FUNC__(xchg_mb)(var, i);
+    else
+#endif /* _M_IX86 */
+    {
+	ETHR_MEMBAR(ETHR_LoadStore|ETHR_StoreStore);
+	var->counter = i;
+    }
+}
+
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_SET_MB 1
 #else
-    (void) ETHR_NATMC_FUNC__(xchg)(var, i);
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_SET_MB 1
 #endif
+
+static ETHR_INLINE void
+ETHR_NATMC_FUNC__(set_mb)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ i)
+{
+    (void) ETHR_NATMC_FUNC__(xchg_mb)(var, i);
 }
 
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_READ 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_READ 1
+#endif
+
 static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(inc_return_acqb)(ETHR_ATMC_T__ *var)
+ETHR_NATMC_FUNC__(read)(ETHR_ATMC_T__ *var)
 {
-    ETHR_AINT_T__ res = ETHR_NATMC_FUNC__(inc_return)(var);
-    __asm__ __volatile__("" : : : "memory");
-    return res;
+    return var->counter;
 }
 
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_ADD_MB 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_ADD_MB 1
+#endif
+
 static ETHR_INLINE void
-ETHR_NATMC_FUNC__(dec_relb)(ETHR_ATMC_T__ *var)
+ETHR_NATMC_FUNC__(add_mb)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ incr)
 {
-    __asm__ __volatile__("" : : : "memory");
-    ETHR_NATMC_FUNC__(dec)(var);
-}
+    __asm__ __volatile__(
+       "lock; add" ETHR_AINT_SUFFIX__ " %1, %0"
+       : "=m"(var->counter)
+       : "ir"(incr), "m"(var->counter)
+       : "memory");
+}      
 
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(dec_return_relb)(ETHR_ATMC_T__ *var)
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_INC_MB 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_INC_MB 1
+#endif
+       
+static ETHR_INLINE void
+ETHR_NATMC_FUNC__(inc_mb)(ETHR_ATMC_T__ *var)
 {
-    __asm__ __volatile__("" : : : "memory");
-    return ETHR_NATMC_FUNC__(dec_return)(var);
+    __asm__ __volatile__(
+	"lock; inc" ETHR_AINT_SUFFIX__ " %0"
+	: "=m"(var->counter)
+	: "m"(var->counter)
+	: "memory");
 }
 
-static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(cmpxchg_acqb)(ETHR_ATMC_T__ *var,
-				ETHR_AINT_T__ new,
-				ETHR_AINT_T__ old)
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_DEC_MB 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_DEC_MB 1
+#endif
+
+static ETHR_INLINE void
+ETHR_NATMC_FUNC__(dec_mb)(ETHR_ATMC_T__ *var)
 {
-    return ETHR_NATMC_FUNC__(cmpxchg)(var, new, old);
+    __asm__ __volatile__(
+	"lock; dec" ETHR_AINT_SUFFIX__ " %0"
+	: "=m"(var->counter)
+	: "m"(var->counter)
+	: "memory");
 }
 
+#if ETHR_INCLUDE_ATOMIC_IMPL__ == 4
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC32_ADD_RETURN_MB 1
+#else
+#  define ETHR_HAVE_ETHR_NATIVE_ATOMIC64_ADD_RETURN_MB 1
+#endif
+
 static ETHR_INLINE ETHR_AINT_T__
-ETHR_NATMC_FUNC__(cmpxchg_relb)(ETHR_ATMC_T__ *var,
-				ETHR_AINT_T__ new,
-				ETHR_AINT_T__ old)
+ETHR_NATMC_FUNC__(add_return_mb)(ETHR_ATMC_T__ *var, ETHR_AINT_T__ incr)
 {
-    return ETHR_NATMC_FUNC__(cmpxchg)(var, new, old);
+    ETHR_AINT_T__ tmp;
+
+    tmp = incr;
+    __asm__ __volatile__(
+	"lock; xadd" ETHR_AINT_SUFFIX__ " %0, %1" /* xadd didn't exist prior to the 486 */
+	: "=r"(tmp)
+	: "m"(var->counter), "0"(tmp)
+	: "memory");
+    /* now tmp is the atomic's previous value */
+    return tmp + incr;
 }
 
 #endif /* ETHR_TRY_INLINE_FUNCS */