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authorRickard Green <[email protected]>2010-06-17 10:23:50 +0200
committerRickard Green <[email protected]>2010-08-10 11:41:14 +0200
commit300b419486c1ca88e33938f182d5d5a8b90fb73f (patch)
tree55c37d5fb042bf6b3b5f56d89c9238a7e22f8b29 /erts/include/internal/pthread
parentc1e94fa9a6fe4ae717d35dfbd1b628dc2e06d26a (diff)
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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.
Diffstat (limited to 'erts/include/internal/pthread')
-rw-r--r--erts/include/internal/pthread/ethr_event.h151
1 files changed, 151 insertions, 0 deletions
diff --git a/erts/include/internal/pthread/ethr_event.h b/erts/include/internal/pthread/ethr_event.h
new file mode 100644
index 0000000000..104ec287e0
--- /dev/null
+++ b/erts/include/internal/pthread/ethr_event.h
@@ -0,0 +1,151 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2009-2010. 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 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.
+ *
+ * %CopyrightEnd%
+ */
+
+/*
+ * Author: Rickard Green
+ */
+
+#if defined(ETHR_HAVE_LINUX_FUTEX) && defined(ETHR_HAVE_NATIVE_ATOMICS)
+/* --- Linux futex implementation of ethread events ------------------------- */
+#define ETHR_LINUX_FUTEX_IMPL__
+
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <linux/futex.h>
+#include <sys/time.h>
+
+/*
+ * Note: Linux futexes operate on 32-bit integers, but
+ * ethr_native_atomic_t are 64-bits on 64-bit
+ * platforms. This has to be taken into account.
+ * Therefore, in each individual value used each
+ * byte look the same.
+ */
+
+#if ETHR_SIZEOF_PTR == 8
+
+#define ETHR_EVENT_OFF_WAITER__ 0xffffffffffffffffL
+#define ETHR_EVENT_OFF__ 0x7777777777777777L
+#define ETHR_EVENT_ON__ 0L
+
+#elif ETHR_SIZEOF_PTR == 4
+
+#define ETHR_EVENT_OFF_WAITER__ 0xffffffffL
+#define ETHR_EVENT_OFF__ 0x77777777L
+#define ETHR_EVENT_ON__ 0L
+
+#else
+
+#error ehrm...
+
+#endif
+
+#if defined(FUTEX_WAIT_PRIVATE) && defined(FUTEX_WAKE_PRIVATE)
+# define ETHR_FUTEX_WAIT__ FUTEX_WAIT_PRIVATE
+# define ETHR_FUTEX_WAKE__ FUTEX_WAKE_PRIVATE
+#else
+# define ETHR_FUTEX_WAIT__ FUTEX_WAIT
+# define ETHR_FUTEX_WAKE__ FUTEX_WAKE
+#endif
+
+typedef struct {
+ ethr_atomic_t futex;
+} ethr_event;
+
+#define ETHR_FUTEX__(FTX, OP, VAL) \
+ (-1 == syscall(__NR_futex, (void *) (FTX), (OP), (int) (VAL), NULL, NULL, 0)\
+ ? errno : 0)
+
+#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
+
+static void ETHR_INLINE
+ETHR_INLINE_FUNC_NAME_(ethr_event_set)(ethr_event *e)
+{
+ long val;
+ ETHR_WRITE_MEMORY_BARRIER;
+ val = ethr_atomic_xchg(&e->futex, ETHR_EVENT_ON__);
+ if (val == ETHR_EVENT_OFF_WAITER__) {
+ int res = ETHR_FUTEX__(&e->futex, ETHR_FUTEX_WAKE__, 1);
+ if (res != 0)
+ ETHR_FATAL_ERROR__(res);
+ }
+}
+
+static void ETHR_INLINE
+ETHR_INLINE_FUNC_NAME_(ethr_event_reset)(ethr_event *e)
+{
+ ethr_atomic_set(&e->futex, ETHR_EVENT_OFF__);
+ ETHR_MEMORY_BARRIER;
+}
+
+#endif
+
+#elif defined(ETHR_PTHREADS)
+/* --- Posix mutex/cond implementation of events ---------------------------- */
+
+typedef struct {
+ ethr_atomic_t state;
+ pthread_mutex_t mtx;
+ pthread_cond_t cnd;
+} ethr_event;
+
+#define ETHR_EVENT_OFF_WAITER__ -1L
+#define ETHR_EVENT_OFF__ 1L
+#define ETHR_EVENT_ON__ 0L
+
+#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
+
+static void ETHR_INLINE
+ETHR_INLINE_FUNC_NAME_(ethr_event_set)(ethr_event *e)
+{
+ long val;
+ ETHR_WRITE_MEMORY_BARRIER;
+ val = ethr_atomic_xchg(&e->state, ETHR_EVENT_ON__);
+ if (val == ETHR_EVENT_OFF_WAITER__) {
+ int res = pthread_mutex_lock(&e->mtx);
+ if (res != 0)
+ ETHR_FATAL_ERROR__(res);
+ res = pthread_cond_signal(&e->cnd);
+ if (res != 0)
+ ETHR_FATAL_ERROR__(res);
+ res = pthread_mutex_unlock(&e->mtx);
+ if (res != 0)
+ ETHR_FATAL_ERROR__(res);
+ }
+}
+
+static void ETHR_INLINE
+ETHR_INLINE_FUNC_NAME_(ethr_event_reset)(ethr_event *e)
+{
+ ethr_atomic_set(&e->state, ETHR_EVENT_OFF__);
+ ETHR_MEMORY_BARRIER;
+}
+
+#endif
+
+#endif
+
+int ethr_event_init(ethr_event *e);
+int ethr_event_destroy(ethr_event *e);
+int ethr_event_wait(ethr_event *e);
+int ethr_event_swait(ethr_event *e, int spincount);
+#if !defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
+void ethr_event_set(ethr_event *e);
+void ethr_event_reset(ethr_event *e);
+#endif