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, 47 insertions, 10 deletions

diff --git a/erts/include/internal/ethread_header_config.h.in b/erts/include/internal/ethread_header_config.h.in
index c9fd87c2f6..5debb44756 100644
--- a/erts/include/internal/ethread_header_config.h.in
+++ b/erts/include/internal/ethread_header_config.h.in
@@ -29,26 +29,54 @@
 /* Define if you have pthreads */
 #undef ETHR_PTHREADS
 
+/* Define if you need the <nptl/pthread.h> header file. */
+#undef ETHR_NEED_NPTL_PTHREAD_H
+
 /* Define if you have the <pthread.h> header file. */
 #undef ETHR_HAVE_PTHREAD_H
 
 /* Define if the pthread.h header file is in pthread/mit directory. */
 #undef ETHR_HAVE_MIT_PTHREAD_H
 
-/* Define if you have the pthread_mutexattr_settype function. */
-#undef ETHR_HAVE_PTHREAD_MUTEXATTR_SETTYPE
+/* Define if you have the pthread_spin_lock function. */
+#undef ETHR_HAVE_PTHREAD_SPIN_LOCK
 
-/* Define if you have the pthread_mutexattr_setkind_np function. */
-#undef ETHR_HAVE_PTHREAD_MUTEXATTR_SETKIND_NP
+/* Define if you want to force usage of pthread rwlocks */
+#undef ETHR_FORCE_PTHREAD_RWLOCK
 
-/* Define if you have the pthread_atfork function. */
-#undef ETHR_HAVE_PTHREAD_ATFORK
+/* Define if you have the pthread_rwlockattr_setkind_np() function. */
+#undef ETHR_HAVE_PTHREAD_RWLOCKATTR_SETKIND_NP
 
-/* Define if you have the pthread_spin_lock function. */
-#undef ETHR_HAVE_PTHREAD_SPIN_LOCK
+/* Define if you have the PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP rwlock
+   attribute. */
+#undef ETHR_HAVE_PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP
 
-/* Define if you have a pthread_rwlock implementation that can be used */
-#undef ETHR_HAVE_PTHREAD_RWLOCK_INIT
+/* Define if you have a linux futex implementation. */
+#undef ETHR_HAVE_LINUX_FUTEX
+
+/* Define if you have gcc atomic operations */
+#undef ETHR_HAVE_GCC_ATOMIC_OPS
+
+/* Define if you prefer gcc native ethread implementations */
+#undef ETHR_PREFER_GCC_NATIVE_IMPLS
+
+/* Define if you have the <sched.h> header file. */
+#undef ETHR_HAVE_SCHED_H
+
+/* Define if you have the sched_yield() function. */
+#undef ETHR_HAVE_SCHED_YIELD
+
+/* Define if you have the pthread_yield() function. */
+#undef ETHR_HAVE_PTHREAD_YIELD
+
+/* Define if pthread_yield() returns an int. */
+#undef ETHR_PTHREAD_YIELD_RET_INT
+
+/* Define if sched_yield() returns an int. */
+#undef ETHR_SCHED_YIELD_RET_INT
+
+/* Define if you want compatibilty with x86 processors before pentium4. */
+#undef ETHR_PRE_PENTIUM4_COMPAT
 
 /* Define if you have the pthread_rwlockattr_setkind_np() function. */
 #undef ETHR_HAVE_PTHREAD_RWLOCKATTR_SETKIND_NP
@@ -63,6 +91,15 @@
 /* Define if you prefer gcc native ethread implementations */
 #undef ETHR_PREFER_GCC_NATIVE_IMPLS
 
+/* Define if you have libatomic_ops atomic operations */
+#undef ETHR_HAVE_LIBATOMIC_OPS
+
+/* Define if you prefer libatomic_ops native ethread implementations */
+#undef ETHR_PREFER_LIBATOMIC_OPS_NATIVE_IMPLS
+
+/* Define to the size of AO_t if libatomic_ops is used */
+#undef ETHR_SIZEOF_AO_T
+
 /* Define if you want to turn on extra sanity checking in the ethread library */
 #undef ETHR_XCHK