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.

1 files changed, 15 insertions, 21 deletions

diff --git a/lib/tools/c_src/erl_memory.c b/lib/tools/c_src/erl_memory.c
index a0e139f059..872d55e789 100644
--- a/lib/tools/c_src/erl_memory.c
+++ b/lib/tools/c_src/erl_memory.c
@@ -1,22 +1,22 @@
-/* ``The contents of this file are subject to the Erlang Public License,
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2003-2010. 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
  * compliance with the License. You should have received a copy of the
  * Erlang Public License along with this software. If not, it can be
- * retrieved via the world wide web at http://www.erlang.org/.
- * 
+ * retrieved online at http://www.erlang.org/.
+ *
  * Software distributed under the License is distributed on an "AS IS"
  * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
  * the License for the specific language governing rights and limitations
  * under the License.
- * 
- * The Initial Developer of the Original Code is Ericsson Utvecklings AB.
- * Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
- * AB. All Rights Reserved.''
- * 
- *     $Id$
+ *
+ * %CopyrightEnd%
  */
 
-
 /*
  * Description:	
  *
@@ -281,17 +281,13 @@ mutex_destroy(ethr_mutex *mtx)
 static INLINE void
 mutex_lock(ethr_mutex *mtx)
 {
-    int res = ethr_mutex_lock(mtx);
-    if (res)
-	error_msg(res, "Mutex lock");
+    ethr_mutex_lock(mtx);
 }
 
 static INLINE void
 mutex_unlock(ethr_mutex *mtx)
 {
-    int res = ethr_mutex_unlock(mtx);
-    if (res)
-	error_msg(res, "Mutex unlock");
+    ethr_mutex_unlock(mtx);
 }
 
 static INLINE void
@@ -314,16 +310,14 @@ static INLINE void
 cond_wait(ethr_cond *cnd, ethr_mutex *mtx)
 {
     int res = ethr_cond_wait(cnd, mtx);
-    if (res)
+    if (res != 0 && res != EINTR)
 	error_msg(res, "Cond wait");
 }
 
 static INLINE void
 cond_signal(ethr_cond *cnd)
 {
-    int res = ethr_cond_signal(cnd);
-    if (res)
-	error_msg(res, "Cond signal");
+    ethr_cond_signal(cnd);
 }
 
 
@@ -2774,7 +2768,7 @@ main(int argc, char *argv[])
 	exit(1);
     }
 
-    if (ethr_init(NULL) != 0) {
+    if (ethr_init(NULL) != 0 || ethr_late_init(NULL) != 0) {
 	fprintf(stderr, "emem: failed to initialize thread package\n");
 	exit(1);
     }