Remove sender punishment

The reduction cost of sending messages is now constant and will no
longer scale according to the length of the receiving process'
message queue.

erts/emulator/beam/bif.c

@@ -2244,20 +2244,15 @@ do_send(Process *p, Eterm to, Eterm msg, Eterm *refp, ErtsSendContext *ctx)
 
  send_message: {
 	ErtsProcLocks rp_locks = 0;
-	Sint res;
 	if (p == rp)
 	    rp_locks |= ERTS_PROC_LOCK_MAIN;
 	/* send to local process */
-	res = erts_send_message(p, rp, &rp_locks, msg, 0);
-	if (erts_use_sender_punish)
-	    res *= 4;
-	else
-	    res = 0;
+	erts_send_message(p, rp, &rp_locks, msg, 0);
 	erts_proc_unlock(rp,
 			     p == rp
 			     ? (rp_locks & ~ERTS_PROC_LOCK_MAIN)
 			     : rp_locks);
-	return res;
+	return 0;
     }
 }
 
@@ -2312,21 +2307,15 @@ BIF_RETTYPE send_3(BIF_ALIST_3)
     result = do_send(p, to, msg, &ref, ctx);
     ERTS_MSACC_POP_STATE_M_X();
 
-    if (result > 0) {
-	ERTS_VBUMP_REDS(p, result);
+    if (result >= 0) {
+	ERTS_VBUMP_REDS(p, 4);
 	if (ERTS_IS_PROC_OUT_OF_REDS(p))
 	    goto yield_return;
 	ERTS_BIF_PREP_RET(retval, am_ok);
 	goto done;
     }
 
     switch (result) {
-    case 0:
-	/* May need to yield even though we do not bump reds here... */
-	if (ERTS_IS_PROC_OUT_OF_REDS(p))
-	    goto yield_return;
-	ERTS_BIF_PREP_RET(retval, am_ok);
-	break;
     case SEND_NOCONNECT:
 	if (ctx->connect) {
 	    ERTS_BIF_PREP_RET(retval, am_ok);
@@ -2443,21 +2432,15 @@ Eterm erl_send(Process *p, Eterm to, Eterm msg)
 
     ERTS_MSACC_POP_STATE_M_X();
 
-    if (result > 0) {
-	ERTS_VBUMP_REDS(p, result);
+    if (result >= 0) {
+	ERTS_VBUMP_REDS(p, 4);
 	if (ERTS_IS_PROC_OUT_OF_REDS(p))
 	    goto yield_return;
 	ERTS_BIF_PREP_RET(retval, msg);
 	goto done;
     }
 
     switch (result) {
-    case 0:
-	/* May need to yield even though we do not bump reds here... */
-	if (ERTS_IS_PROC_OUT_OF_REDS(p))
-	    goto yield_return;
-	ERTS_BIF_PREP_RET(retval, msg);
-	break;
     case SEND_NOCONNECT:
 	ERTS_BIF_PREP_RET(retval, msg);
 	break;

erts/emulator/beam/erl_init.c

@@ -155,9 +155,6 @@ erts_atomic32_t erts_writing_erl_crash_dump;
 erts_tsd_key_t erts_is_crash_dumping_key;
 int erts_initialized = 0;
 
-
-int erts_use_sender_punish;
-
 /*
  * Configurable parameters.
  */
@@ -758,8 +755,6 @@ early_init(int *argc, char **argv) /*
 
     erts_initialized = 0;
 
-    erts_use_sender_punish = 1;
-
     erts_pre_early_init_cpu_topology(&max_reader_groups,
 				     &ncpu,
 				     &ncpuonln,
@@ -1765,8 +1760,6 @@ erl_start(int argc, char **argv)
 		    erts_usage();
 		}
 	    }
-	    else if (sys_strcmp("nsp", sub_param) == 0)
-		erts_use_sender_punish = 0;
 	    else if (has_prefix("tbt", sub_param)) {
 		arg = get_arg(sub_param+3, argv[i+1], &i);
 		res = erts_init_scheduler_bind_type_string(arg);

erts/emulator/beam/global.h

@@ -1122,7 +1122,6 @@ extern int erts_no_line_info;
 extern Eterm erts_error_logger_warnings;
 extern int erts_initialized;
 extern int erts_compat_rel;
-extern int erts_use_sender_punish;
 void erl_start(int, char**);
 void erts_usage(void);
 Eterm erts_preloaded(Process* p);