slowdown the cpu usage for srs to calc connections when too many connections. 0.9.180

@@ -14,7 +14,7 @@ gprof2dot.py:
 0. 若需要图形化，编译dot：
     cd 3rdparty/gprof && bash build_gprof2dot.sh
 1. srs配置时: 
-    ./configure --with-pg
+    ./configure --with-gprof
     脚本会加入编译参数"-pg -lc_p"，gcc -g -pg -lc_p -c xxx -o xxx.o，即在configure中打开 Performance="-pg -lc_p"
     链接时，加入链接选项"-pg"，否则无法工作：gcc -pg -o srs xxxx.o，即在configure中打开 PerformanceLink="-pg"
 2. 编译和启动程序：make && ./objs/srs -c conf/srs.conf

@@ -90,7 +90,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // update network devices info interval:
 //      SRS_SYS_CYCLE_INTERVAL * SRS_SYS_NETWORK_RTMP_SERVER_RESOLUTION_TIMES
-#define SRS_SYS_NETWORK_RTMP_SERVER_RESOLUTION_TIMES 90
+#define SRS_SYS_NETWORK_RTMP_SERVER_RESOLUTION_TIMES 120
 
 SrsListener::SrsListener(SrsServer* server, SrsListenerType type)
 {

@@ -833,10 +833,18 @@ void srs_update_rtmp_server(int nb_conn, SrsKbps* kbps)
         int nb_conn_sys_other = 0;
         
         // @see: http://tester-higkoo.googlecode.com/svn-history/r14/trunk/Tools/iostat/iostat.c
-        while (fgets(buf, sizeof(buf), f)) {
+        for (int i = 0; fgets(buf, sizeof(buf), f); i++) {
             int st = 0;
             int ret = sscanf(buf, "%*s %*s %*s %2x\n", &st);
             
+            // there are maybe many many connections,
+            // for example, when srs used for monitor other process,
+            // like nginx, there are maybe many TIME_WAIT conections.
+            // we sleep 1ms when read 1000 records, so 100ms for 10w connections.
+            if ((i % 1000) == 0) {
+                st_usleep(1000);
+            }
+            
             if (ret == 1) {
                 if (st == SYS_TCP_ESTABLISHED) {
                     nb_conn_sys_established++;

@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR "0"
 #define VERSION_MINOR "9"
-#define VERSION_REVISION "179"
+#define VERSION_REVISION "180"
 #define RTMP_SIG_SRS_VERSION VERSION_MAJOR"."VERSION_MINOR"."VERSION_REVISION
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"