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, 113 insertions, 3 deletions

diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 4a4507b212..14bd10b42c 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -78,6 +78,7 @@ static erts_tid_t main_thread;
 
 erts_cpu_info_t *erts_cpuinfo;
 
+int erts_reader_groups;
 int erts_use_sender_punish;
 
 /*
@@ -110,6 +111,7 @@ int erts_compat_rel;
 static int use_multi_run_queue;
 static int no_schedulers;
 static int no_schedulers_online;
+static int max_reader_groups;
 
 #ifdef DEBUG
 Uint32 verbose;             /* See erl_debug.h for information about verbose */
@@ -505,6 +507,7 @@ void erts_usage(void)
 	       ERTS_MIN_COMPAT_REL, this_rel_num());
 
     erts_fprintf(stderr, "-r          force ets memory block to be moved on realloc\n");
+    erts_fprintf(stderr, "-rg amount  set reader groups limit\n");
     erts_fprintf(stderr, "-sbt type   set scheduler bind type, valid types are:\n");
     erts_fprintf(stderr, "            u|ns|ts|ps|s|nnts|nnps|tnnps|db\n");
     erts_fprintf(stderr, "-sct cput   set cpu topology,\n");
@@ -538,6 +541,50 @@ void erts_usage(void)
     erl_exit(-1, "");
 }
 
+#ifdef USE_THREADS
+/*
+ * allocators for thread lib
+ */
+
+static void *ethr_std_alloc(size_t size)
+{
+    return erts_alloc_fnf(ERTS_ALC_T_ETHR_STD, (Uint) size);
+}
+static void *ethr_std_realloc(void *ptr, size_t size)
+{
+    return erts_realloc_fnf(ERTS_ALC_T_ETHR_STD, ptr, (Uint) size);
+}
+static void ethr_std_free(void *ptr)
+{
+    erts_free(ERTS_ALC_T_ETHR_STD, ptr);
+}
+static void *ethr_sl_alloc(size_t size)
+{
+    return erts_alloc_fnf(ERTS_ALC_T_ETHR_SL, (Uint) size);
+}
+static void *ethr_sl_realloc(void *ptr, size_t size)
+{
+    return erts_realloc_fnf(ERTS_ALC_T_ETHR_SL, ptr, (Uint) size);
+}
+static void ethr_sl_free(void *ptr)
+{
+    erts_free(ERTS_ALC_T_ETHR_SL, ptr);
+}
+static void *ethr_ll_alloc(size_t size)
+{
+    return erts_alloc_fnf(ERTS_ALC_T_ETHR_LL, (Uint) size);
+}
+static void *ethr_ll_realloc(void *ptr, size_t size)
+{
+    return erts_realloc_fnf(ERTS_ALC_T_ETHR_LL, ptr, (Uint) size);
+}
+static void ethr_ll_free(void *ptr)
+{
+    erts_free(ERTS_ALC_T_ETHR_LL, ptr);
+}
+
+#endif
+
 static void
 early_init(int *argc, char **argv) /*
 				   * Only put things here which are
@@ -615,9 +662,15 @@ early_init(int *argc, char **argv) /*
 			    ? ncpuavail
 			    : (ncpuonln > 0 ? ncpuonln : no_schedulers));
 
+#ifdef ERTS_SMP
+    erts_max_main_threads = no_schedulers_online;
+#endif
+
     schdlrs = no_schedulers;
     schdlrs_onln = no_schedulers_online;
 
+    max_reader_groups = ERTS_MAX_READER_GROUPS;
+
     if (argc && argv) {
 	int i = 1;
 	while (i < *argc) {
@@ -627,6 +680,24 @@ early_init(int *argc, char **argv) /*
 	    }
 	    if (argv[i][0] == '-') {
 		switch (argv[i][1]) {
+		case 'r': {
+		    char *sub_param = argv[i]+2;
+		    if (has_prefix("g", sub_param)) {
+			char *arg = get_arg(sub_param+1, argv[i+1], &i);
+			if (sscanf(arg, "%d", &max_reader_groups) != 1) {
+			    erts_fprintf(stderr,
+					 "bad reader groups limit: %s\n", arg);
+			    erts_usage();
+			}
+			if (max_reader_groups < 0) {
+			    erts_fprintf(stderr,
+					 "bad reader groups limit: %d\n",
+					 max_reader_groups);
+			    erts_usage();
+			}
+		    }
+		    break;
+		}
 		case 'S' : {
 		    int tot, onln;
 		    char *arg = get_arg(argv[i]+2, argv[i+1], &i);
@@ -699,6 +770,36 @@ early_init(int *argc, char **argv) /*
     erts_early_init_scheduling(); /* Require allocators */
     erts_init_utils(); /* Require allocators */
 
+#ifdef USE_THREADS
+    {
+	erts_thr_late_init_data_t elid = ERTS_THR_LATE_INIT_DATA_DEF_INITER;
+	elid.mem.std.alloc = ethr_std_alloc;
+	elid.mem.std.realloc = ethr_std_realloc;
+	elid.mem.std.free = ethr_std_free;
+	elid.mem.sl.alloc = ethr_sl_alloc;
+	elid.mem.sl.realloc = ethr_sl_realloc;
+	elid.mem.sl.free = ethr_sl_free;
+	elid.mem.ll.alloc = ethr_ll_alloc;
+	elid.mem.ll.realloc = ethr_ll_realloc;
+	elid.mem.ll.free = ethr_ll_free;
+
+#ifdef ERTS_SMP
+	elid.main_threads = erts_max_main_threads;
+#else
+	elid.main_threads = 1;
+#endif
+	elid.reader_groups = (elid.main_threads > 1
+			      ? elid.main_threads
+			      : 0);
+	if (max_reader_groups <= 1)
+	    elid.reader_groups = 0;
+	if (elid.reader_groups > max_reader_groups)
+	    elid.reader_groups = max_reader_groups;
+	erts_reader_groups = elid.reader_groups;
+
+	erts_thr_late_init(&elid);
+    }
+#endif
 #ifdef ERTS_ENABLE_LOCK_CHECK
     erts_lc_late_init();
 #endif
@@ -1193,9 +1294,17 @@ erl_start(int argc, char **argv)
 		     erts_async_thread_suggested_stack_size));
 	    break;
 
- 	case 'r':
-	    erts_ets_realloc_always_moves = 1;
+	case 'r': {
+	    char *sub_param = argv[i]+2;
+	    if (has_prefix("g", sub_param)) {
+		get_arg(sub_param+1, argv[i+1], &i);
+		/* already handled */
+	    }
+	    else {
+		erts_ets_realloc_always_moves = 1;
+	    }
 	    break;
+	}
 	case 'n':   /* XXX obsolete */
 	    break;
 	case 'c':
@@ -1280,6 +1389,7 @@ erl_start(int argc, char **argv)
 
     erts_sys_main_thread(); /* May or may not return! */
 #else
+    erts_thr_set_main_status(1, 1);
     set_main_stack_size();
     process_main();
 #endif
@@ -1353,7 +1463,7 @@ system_cleanup(int exit_code)
     erts_cleanup_incgc();
 #endif
 
-#if defined(USE_THREADS) && !defined(ERTS_SMP)
+#if defined(USE_THREADS)
     exit_async();
 #endif
 #if HAVE_ERTS_MSEG