Rewrite ethread library

Large parts of the ethread library have been rewritten. The
ethread library is an Erlang runtime system internal, portable
thread library used by the runtime system itself.

Most notable improvement is a reader optimized rwlock
implementation which dramatically improve the performance of
read-lock/read-unlock operations on multi processor systems by
avoiding ping-ponging of the rwlock cache lines. The reader
optimized rwlock implementation is used by miscellaneous
rwlocks in the runtime system that are known to be read-locked
frequently, and can be enabled on ETS tables by passing the
`{read_concurrency, true}' option upon table creation. See the
documentation of `ets:new/2' for more information.

The ethread library can now also use the libatomic_ops library
for atomic memory accesses. This makes it possible for the
Erlang runtime system to utilize optimized atomic operations
on more platforms than before. Use the
`--with-libatomic_ops=PATH' configure command line argument
when specifying where the libatomic_ops installation is
located. The libatomic_ops library can be downloaded from:
http://www.hpl.hp.com/research/linux/atomic_ops/

The changed API of the ethread library has also caused
modifications in the Erlang runtime system. Preparations for
the to come "delayed deallocation" feature has also been done
since it depends on the ethread library.

Note: When building for x86, the ethread library will now use
instructions that first appeared on the pentium 4 processor. If
you want the runtime system to be compatible with older
processors (back to 486) you need to pass the
`--enable-ethread-pre-pentium4-compatibility' configure command
line argument when configuring the system.

2 files changed, 3 insertions, 34 deletions

diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index 737ffd9f94..400ef6c0ce 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -384,18 +384,6 @@ MALLOC_USE_HASH(1);
 #endif
 
 #ifdef USE_THREADS
-static void *ethr_internal_alloc(size_t size)
-{
-    return erts_alloc_fnf(ERTS_ALC_T_ETHR_INTERNAL, (Uint) size);
-}
-static void *ethr_internal_realloc(void *ptr, size_t size)
-{
-    return erts_realloc_fnf(ERTS_ALC_T_ETHR_INTERNAL, ptr, (Uint) size);
-}
-static void ethr_internal_free(void *ptr)
-{
-    erts_free(ERTS_ALC_T_ETHR_INTERNAL, ptr);
-}
 
 #ifdef ERTS_THR_HAVE_SIG_FUNCS
 /*
@@ -488,9 +476,6 @@ erts_sys_pre_init(void)
 #ifdef USE_THREADS
     {
     erts_thr_init_data_t eid = ERTS_THR_INIT_DATA_DEF_INITER;
-    eid.alloc = ethr_internal_alloc;
-    eid.realloc = ethr_internal_realloc;
-    eid.free = ethr_internal_free;
 
     eid.thread_create_child_func = thr_create_prepare_child;
     /* Before creation in parent */
@@ -538,13 +523,14 @@ erts_sys_pre_init(void)
 #endif
 #endif /* USE_THREADS */
     erts_smp_atomic_init(&sys_misc_mem_sz, 0);
-    erts_smp_rwmtx_init(&environ_rwmtx, "environ");
 }
 
 void
 erl_sys_init(void)
 {
+    erts_smp_rwmtx_init(&environ_rwmtx, "environ");
 #if !DISABLE_VFORK
+ {
     int res;
     char bindir[MAXPATHLEN];
     size_t bindirsz = sizeof(bindir);
@@ -574,6 +560,7 @@ erl_sys_init(void)
             bindir,
             DIR_SEPARATOR_CHAR,
             CHILD_SETUP_PROG_NAME);
+ }
 #endif
 
 #ifdef USE_SETLINEBUF
diff --git a/erts/emulator/sys/win32/sys.c b/erts/emulator/sys/win32/sys.c
index bd02cf85eb..54f71b202d 100644
--- a/erts/emulator/sys/win32/sys.c
+++ b/erts/emulator/sys/win32/sys.c
@@ -2974,19 +2974,6 @@ check_supported_os_version(void)
 }
 
 #ifdef USE_THREADS
-static void *ethr_internal_alloc(size_t size)
-{
-    return erts_alloc_fnf(ERTS_ALC_T_ETHR_INTERNAL, (Uint) size);
-}
-static void *ethr_internal_realloc(void *ptr, size_t size)
-{
-    return erts_realloc_fnf(ERTS_ALC_T_ETHR_INTERNAL, ptr, (Uint) size);
-}
-static void ethr_internal_free(void *ptr)
-{
-    erts_free(ERTS_ALC_T_ETHR_INTERNAL, ptr);
-}
-
 #ifdef ERTS_ENABLE_LOCK_COUNT
 static void
 thr_create_prepare_child(void *vtcdp)
@@ -3005,14 +2992,9 @@ erts_sys_pre_init(void)
 #ifdef USE_THREADS
     {
 	erts_thr_init_data_t eid = ERTS_THR_INIT_DATA_DEF_INITER;
-	eid.alloc = ethr_internal_alloc;
-	eid.realloc = ethr_internal_realloc;
-	eid.free = ethr_internal_free;
-
 #ifdef ERTS_ENABLE_LOCK_COUNT
 	eid.thread_create_child_func = thr_create_prepare_child;
 #endif
-
 	erts_thr_init(&eid);
 #ifdef ERTS_ENABLE_LOCK_COUNT
 	erts_lcnt_init();