framework: set default processor num when there is no process sched conf (#1946)

cyber/conf/cyber.pb.conf

@@ -41,6 +41,7 @@ record_conf {
 
 scheduler_conf {
     routine_num: 100
+    default_proc_num: 2
 }
 
 perf_conf {

cyber/proto/scheduler_conf.proto

@@ -8,6 +8,7 @@ import "cyber/proto/choreography_conf.proto";
 message SchedulerConf {
   optional string policy = 1;
   optional uint32 routine_num = 2;
-  optional ClassicConf classic_conf = 3;
-  optional ChoreographyConf choreography_conf = 4;
+  optional uint32 default_proc_num = 3;
+  optional ClassicConf classic_conf = 4;
+  optional ChoreographyConf choreography_conf = 5;
 }

cyber/scheduler/policy/scheduler_classic.cc

@@ -59,10 +59,13 @@ SchedulerClassic::SchedulerClassic() {
       }
     }
   } else {
-    // fallback default sched config. To avoid every process launchs
-    // too many threads, limit to 2 cpus for process w/o explicit config.
-    proc_num_ = 2;
-    // FIXME: other vals ... ?
+    auto& global_conf = GlobalData::Instance()->Config();
+    if (global_conf.has_scheduler_conf() &&
+        global_conf.scheduler_conf().has_default_proc_num()) {
+      proc_num_ = global_conf.scheduler_conf().default_proc_num();
+    } else {
+      proc_num_ = 2;
+    }
   }
 
   // Currently for compatible with task/task_manager.cc: