7 files changed, 35 insertions, 17 deletions
diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index cef633bd93..cb4fab51f1 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -641,6 +641,7 @@ atom suspending
 atom sys_misc
 atom system
 atom system_error
+atom system_flag_scheduler_wall_time
 atom system_limit
 atom system_version
 atom system_architecture
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 50699eac31..0e5f7bb22b 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -59,6 +59,7 @@ Export *erts_convert_time_unit_trap = NULL;
 static Export *await_msacc_mod_trap = NULL;
 static erts_atomic32_t msacc;
 
+static Export *system_flag_scheduler_wall_time_trap;
 static Export *await_sched_wall_time_mod_trap;
 static erts_atomic32_t sched_wall_time;
 
@@ -247,10 +248,8 @@ BIF_RETTYPE link_1(BIF_ALIST_1)
 		 */
 		state = erts_atomic32_read_acqb(&BIF_P->state);
 		if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT)) {
-#ifdef ERTS_SMP
 		    if (state & ERTS_PSFLG_PENDING_EXIT)
 			erts_handle_pending_exit(BIF_P, ERTS_PROC_LOCK_MAIN);
-#endif
 		    ERTS_BIF_EXITED(BIF_P);
 		}
 		BIF_RET(am_true);
@@ -4496,7 +4495,7 @@ BIF_RETTYPE group_leader_2(BIF_ALIST_2)
 	BIF_ERROR(BIF_P, BADARG);
     }
 }
-    
+
 BIF_RETTYPE system_flag_2(BIF_ALIST_2)    
 {
     Sint n;
@@ -4714,17 +4713,9 @@ BIF_RETTYPE system_flag_2(BIF_ALIST_2)
 
 	BIF_RET(am_true);
     } else if (BIF_ARG_1 == am_scheduler_wall_time) {
-	if (BIF_ARG_2 == am_true || BIF_ARG_2 == am_false) {
-	    erts_aint32_t new = BIF_ARG_2 == am_true ? 1 : 0;
-	    erts_aint32_t old = erts_atomic32_xchg_nob(&sched_wall_time,
-							   new);
-	    Eterm ref = erts_sched_wall_time_request(BIF_P, 1, new, 0, 0);
-	    ASSERT(is_value(ref));
-	    BIF_TRAP2(await_sched_wall_time_mod_trap,
-		      BIF_P,
-		      ref,
-		      old ? am_true : am_false);
-	}
+	if (BIF_ARG_2 == am_true || BIF_ARG_2 == am_false)
+            BIF_TRAP1(system_flag_scheduler_wall_time_trap,
+                      BIF_P, BIF_ARG_2);
     } else if (BIF_ARG_1 == am_dirty_cpu_schedulers_online) {
 	Sint old_no;
 	if (!is_small(BIF_ARG_2))
@@ -4836,6 +4827,17 @@ BIF_RETTYPE system_flag_2(BIF_ALIST_2)
     BIF_ERROR(BIF_P, BADARG);
 }
 
+BIF_RETTYPE erts_internal_scheduler_wall_time_1(BIF_ALIST_1)
+{
+    erts_aint32_t new = BIF_ARG_1 == am_true ? 1 : 0;
+    erts_aint32_t old = erts_atomic32_xchg_nob(&sched_wall_time,
+                                               new);
+    Eterm ref = erts_sched_wall_time_request(BIF_P, 1, new, 0, 0);
+    ASSERT(is_value(ref));
+    BIF_TRAP2(await_sched_wall_time_mod_trap,
+              BIF_P, ref, old ? am_true : am_false);
+}
+
 /**********************************************************************/
 
 BIF_RETTYPE phash_2(BIF_ALIST_2)
@@ -5094,8 +5096,10 @@ void erts_init_bif(void)
     await_proc_exit_trap = erts_export_put(am_erlang,am_await_proc_exit,3);
     await_port_send_result_trap
 	= erts_export_put(am_erts_internal, am_await_port_send_result, 3);
+    system_flag_scheduler_wall_time_trap
+        = erts_export_put(am_erts_internal, am_system_flag_scheduler_wall_time, 1);
     await_sched_wall_time_mod_trap
-        = erts_export_put(am_erlang, am_await_sched_wall_time_modifications, 2);
+        = erts_export_put(am_erts_internal, am_await_sched_wall_time_modifications, 2);
     await_msacc_mod_trap
 	= erts_export_put(am_erts_internal, am_await_microstate_accounting_modifications, 3);
 
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 1c5e19cd88..c0d5e8ce74 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -185,6 +185,8 @@ bif erts_internal:system_check/1
 
 bif erts_internal:release_literal_area_switch/0
 
+bif erts_internal:scheduler_wall_time/1
+
 # inet_db support
 bif erlang:port_set_data/2
 bif erlang:port_get_data/1
diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index cb8812c455..e7acea0c5f 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -358,7 +358,7 @@ print_process_info(fmtfn_t to, void *to_arg, Process *p)
 static void
 print_garb_info(fmtfn_t to, void *to_arg, Process* p)
 {
-    /* ERTS_SMP: A scheduler is probably concurrently doing gc... */
+    /* A scheduler is probably concurrently doing gc... */
     if (!ERTS_IS_CRASH_DUMPING)
       return;
     erts_print(to, to_arg, "New heap start: %bpX\n", p->heap);
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 9aafab86c0..52056023fd 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -4758,7 +4758,7 @@ erts_bif_info_init(void)
     alloc_info_trap = erts_export_put(am_erlang, am_alloc_info, 1);
     alloc_sizes_trap = erts_export_put(am_erlang, am_alloc_sizes, 1);
     gather_sched_wall_time_res_trap
-	= erts_export_put(am_erlang, am_gather_sched_wall_time_result, 1);
+	= erts_export_put(am_erts_internal, am_gather_sched_wall_time_result, 1);
     gather_gc_info_res_trap
 	= erts_export_put(am_erlang, am_gather_gc_info_result, 1);
     gather_io_bytes_trap
diff --git a/erts/emulator/beam/instrs.tab b/erts/emulator/beam/instrs.tab
index d934abb217..b92152238e 100644
--- a/erts/emulator/beam/instrs.tab
+++ b/erts/emulator/beam/instrs.tab
@@ -931,3 +931,8 @@ i_raise() {
     //| -no_next
 }
 
+build_stacktrace() {
+    SWAPOUT;
+    x(0) = build_stacktrace(c_p, x(0));
+    SWAPIN;
+}
diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab
index c30af029ce..fd1b3b9c74 100644
--- a/erts/emulator/beam/ops.tab
+++ b/erts/emulator/beam/ops.tab
@@ -1578,3 +1578,9 @@ i_recv_mark
 recv_set Fail | label Lbl | loop_rec Lf Reg => \
    i_recv_set | label Lbl | loop_rec Lf Reg
 i_recv_set
+
+#
+# OTP 21.
+#
+
+build_stacktrace