add root directive cpu_affinity, to set the cpu affinity of srs

@@ -65,6 +65,9 @@ asprocess off;
 # whether using build-in speex to aac transcoding
 # default: off
 speex2aac off;
+# set cpu affinity,the index of the cpu core,0,1,2,...
+# default -1,don't set affinity
+cpu_affinity -1;
 
 #############################################################################################
 # heartbeat/stats sections

@@ -47,6 +47,10 @@ using namespace std;
 #include <srs_app_utility.hpp>
 #include <srs_core_performance.hpp>
 #include "../../objs/version.h"
+#ifndef __USE_GNU
+#define __USE_GNU
+#endif
+#include<sched.h>
 
 using namespace _srs_internal;
 
@@ -1007,8 +1011,6 @@ int SrsConfig::reload_conf(SrsConfig* conf)
         return ret;
     }
     
-    set_config_static();
-    
     return ret;
 }
 
@@ -1584,6 +1586,7 @@ int SrsConfig::check_config()
             && n != "http_api" && n != "stats" && n != "vhost" && n != "pithy_print_ms"
             && n != "http_stream" && n != "http_server" && n != "stream_caster"
             && n != "utc_time" && n != "work_dir" && n != "asprocess" && n != "speex2aac"
+            && n != "cpu_affinity"
         ) {
             ret = ERROR_SYSTEM_CONFIG_INVALID;
             srs_error("unsupported directive %s, ret=%d", n.c_str(), ret);
@@ -2102,7 +2105,23 @@ void SrsConfig::set_config_static()
 	 }
 	 else
 	     _speex2aac = false;
-
+	     
+	 conf = root->get("cpu_affinity");
+	 int cpu_index = -1;
+	 if(conf){
+	 	cpu_index = atoi(conf->arg0().c_str());
+	 }
+	 if(cpu_index >= 0){
+		cpu_set_t mask;
+		CPU_ZERO(&mask);
+	 	CPU_SET(cpu_index, &mask);
+	 	if (sched_setaffinity(0, sizeof(mask), &mask) == -1){
+           srs_error("error when set cpu affinity to CPU:%d",cpu_index);
+        }
+        else{
+       	  srs_trace("success in set cpu affinity to CPU:%d",cpu_index);
+        }
+	 }
 }
 
 int SrsConfig::parse_buffer(SrsConfigBuffer* buffer)