Add +stbt erl command line switch

5 files changed, 62 insertions, 18 deletions

diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml
index f931445a3e..5714383b0f 100644
--- a/erts/doc/src/erl.xml
+++ b/erts/doc/src/erl.xml
@@ -657,7 +657,24 @@
         <taglist>
           <tag><marker id="+sbt"><c>+sbt BindType</c></marker></tag>
           <item>
-            <p>Set scheduler bind type. Currently valid <c>BindType</c>s:
+            <p>Set scheduler bind type.</p>
+	    <p>Schedulers can also be bound using the
+	    <seealso marker="#+stbt">+stbt</seealso> flag. The only difference
+	    between these two flags is how the following errors are handled:</p>
+	    <list>
+	      <item>Binding of schedulers is not supported on the specific
+	      platform.</item>
+	      <item>No available CPU topology. That is the runtime system
+	      was not able to automatically detected the CPU topology, and
+	      no <seealso marker="#+sct">user defined CPU topology</seealso>
+	      was set.</item>
+	    </list>
+	    <p>If any of these errors occur when <c>+sbt</c> has been passed,
+	    the runtime system will print an error message, and refuse to
+	    start. If any of these errors occur when <c>+stbt</c> has been
+	    passed, the runtime system will silently ignore the error, and
+	    start up using unbound schedulers.</p>
+	    <p>Currently valid <c>BindType</c>s:
 	    </p>
 	    <taglist>
 	      <tag><c>u</c></tag>
@@ -907,6 +924,14 @@
 	    <p>For more information, see
 	    <seealso marker="erlang#system_info_cpu_topology">erlang:system_info(cpu_topology)</seealso>.</p>
           </item>
+          <tag><marker id="+stbt"><c>+stbt BindType</c></marker></tag>
+          <item>
+            <p>Try to set scheduler bind type. The same as the
+	    <seealso marker="#+sbt">+sbt</seealso> flag with the exception of
+	    how some errors are handled. For more information, see the
+	    documentation of the <seealso marker="#+sbt">+sbt</seealso> flag.
+	    </p>
+	  </item>
 	  <tag><marker id="+sws"><c>+sws default|legacy|proposal</c></marker></tag>
 	  <item>
              <p>Set scheduler wakeup strategy. Default is <c>legacy</c> (has been
diff --git a/erts/emulator/beam/erl_cpu_topology.c b/erts/emulator/beam/erl_cpu_topology.c
index fe3693d0ca..a55e29b070 100644
--- a/erts/emulator/beam/erl_cpu_topology.c
+++ b/erts/emulator/beam/erl_cpu_topology.c
@@ -623,30 +623,38 @@ write_schedulers_bind_change(erts_cpu_topology_t *cpudata, int size)
 int
 erts_init_scheduler_bind_type_string(char *how)
 {
+    ErtsCpuBindOrder order;
+
     if (sys_strcmp(how, "u") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_NONE;
-    else if (erts_bind_to_cpu(cpuinfo, -1) == -ENOTSUP)
-	return ERTS_INIT_SCHED_BIND_TYPE_NOT_SUPPORTED;
-    else if (!system_cpudata && !user_cpudata)
-	return ERTS_INIT_SCHED_BIND_TYPE_ERROR_NO_CPU_TOPOLOGY;
+	order = ERTS_CPU_BIND_NONE;
     else if (sys_strcmp(how, "db") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_DEFAULT_BIND;
+	order = ERTS_CPU_BIND_DEFAULT_BIND;
     else if (sys_strcmp(how, "s") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_SPREAD;
+	order = ERTS_CPU_BIND_SPREAD;
     else if (sys_strcmp(how, "ps") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_PROCESSOR_SPREAD;
+	order = ERTS_CPU_BIND_PROCESSOR_SPREAD;
     else if (sys_strcmp(how, "ts") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_THREAD_SPREAD;
+	order = ERTS_CPU_BIND_THREAD_SPREAD;
     else if (sys_strcmp(how, "tnnps") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_THREAD_NO_NODE_PROCESSOR_SPREAD;
+	order = ERTS_CPU_BIND_THREAD_NO_NODE_PROCESSOR_SPREAD;
     else if (sys_strcmp(how, "nnps") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_NO_NODE_PROCESSOR_SPREAD;
+	order = ERTS_CPU_BIND_NO_NODE_PROCESSOR_SPREAD;
     else if (sys_strcmp(how, "nnts") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_NO_NODE_THREAD_SPREAD;
+	order = ERTS_CPU_BIND_NO_NODE_THREAD_SPREAD;
     else if (sys_strcmp(how, "ns") == 0)
-	cpu_bind_order = ERTS_CPU_BIND_NO_SPREAD;
+	order = ERTS_CPU_BIND_NO_SPREAD;
     else
-	return ERTS_INIT_SCHED_BIND_TYPE_ERROR_NO_BAD_TYPE;
+	return ERTS_INIT_SCHED_BIND_TYPE_ERROR_BAD_TYPE;
+
+    if (order != ERTS_CPU_BIND_NONE) {
+	if (erts_bind_to_cpu(cpuinfo, -1) == -ENOTSUP)
+	    return ERTS_INIT_SCHED_BIND_TYPE_NOT_SUPPORTED;
+	else if (!system_cpudata && !user_cpudata)
+	    return ERTS_INIT_SCHED_BIND_TYPE_ERROR_NO_CPU_TOPOLOGY;
+    }
+
+    cpu_bind_order = order;
+
     return ERTS_INIT_SCHED_BIND_TYPE_SUCCESS;
 }
 
diff --git a/erts/emulator/beam/erl_cpu_topology.h b/erts/emulator/beam/erl_cpu_topology.h
index c5a9520b61..11915e1ea8 100644
--- a/erts/emulator/beam/erl_cpu_topology.h
+++ b/erts/emulator/beam/erl_cpu_topology.h
@@ -40,7 +40,7 @@ void erts_init_cpu_topology(void);
 #define ERTS_INIT_SCHED_BIND_TYPE_SUCCESS		0
 #define ERTS_INIT_SCHED_BIND_TYPE_NOT_SUPPORTED		1
 #define ERTS_INIT_SCHED_BIND_TYPE_ERROR_NO_CPU_TOPOLOGY	2
-#define ERTS_INIT_SCHED_BIND_TYPE_ERROR_NO_BAD_TYPE	3
+#define ERTS_INIT_SCHED_BIND_TYPE_ERROR_BAD_TYPE	3
 
 int erts_init_scheduler_bind_type_string(char *how);
 
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 1eb3dba240..eb7027dcdc 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -447,7 +447,7 @@ void erts_usage(void)
     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, "-stbt type  u|ns|ts|ps|s|nnts|nnps|tnnps|db\n");
     erts_fprintf(stderr, "-sbwt val   set scheduler busy wait threshold, valid values are:\n");
     erts_fprintf(stderr, "            none|very_short|short|medium|long|very_long.\n");
     erts_fprintf(stderr, "-scl bool   enable/disable compaction of scheduler load,\n");
@@ -1121,7 +1121,7 @@ erl_start(int argc, char **argv)
 		    case ERTS_INIT_SCHED_BIND_TYPE_ERROR_NO_CPU_TOPOLOGY:
 			estr = "no cpu topology available";
 			break;
-		    case ERTS_INIT_SCHED_BIND_TYPE_ERROR_NO_BAD_TYPE:
+		    case ERTS_INIT_SCHED_BIND_TYPE_ERROR_BAD_TYPE:
 			estr = "invalid type";
 			break;
 		    default:
@@ -1203,6 +1203,16 @@ erl_start(int argc, char **argv)
 	    }
 	    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);
+		if (res == ERTS_INIT_SCHED_BIND_TYPE_ERROR_BAD_TYPE) {
+		    erts_fprintf(stderr,
+				 "setting scheduler bind type '%s' failed: invalid type\n",
+				 arg);
+		    erts_usage();
+		}
+	    }
 	    else if (sys_strcmp("wt", sub_param) == 0) {
 		arg = get_arg(sub_param+2, argv[i+1], &i);
 		if (erts_sched_set_wakeup_other_thresold(arg) != 0) {
diff --git a/erts/etc/common/erlexec.c b/erts/etc/common/erlexec.c
index 52add1c1ba..41fb9168de 100644
--- a/erts/etc/common/erlexec.c
+++ b/erts/etc/common/erlexec.c
@@ -124,6 +124,7 @@ static char *pluss_val_switches[] = {
     "bwt",
     "cl",
     "ct",
+    "tbt",
     "wt",
     "ws",
     "ss",