Optimize RFsimulator to improve E2E performance

This improves the RFsimulator code to reach a ~40% E2E throughput
improvement (depending on the machines).

Changes:
- reduce ring buffer size
- code cleanup for readability
- set TCP kernel parameters

radio/COMMON/common_lib.h

@@ -572,17 +572,11 @@ struct openair0_device_t {
 typedef int(*oai_device_initfunc_t)(openair0_device *device, openair0_config_t *openair0_cfg);
 /* type of transport init function, implemented in shared lib */
 typedef int(*oai_transport_initfunc_t)(openair0_device *device, openair0_config_t *openair0_cfg, eth_params_t *eth_params);
-#define UE_MAGICDL 0xA5A5A5A5A5A5A5A5  // UE DL FDD record
-#define UE_MAGICUL 0x5A5A5A5A5A5A5A5A  // UE UL FDD record
-
-#define ENB_MAGICDL 0xB5B5B5B5B5B5B5B5  // eNB DL FDD record
-#define ENB_MAGICUL 0x5B5B5B5B5B5B5B5B  // eNB UL FDD record
 
 #define OPTION_LZ4  0x00000001          // LZ4 compression (option_value is set to compressed size)
 
 
 typedef struct {
-  uint64_t magic;          // Magic value (see defines above)
   uint32_t size;           // Number of samples per antenna to follow this header
   uint32_t nbAnt;          // Total number of antennas following this header
   // Samples per antenna follow this header,

radio/rfsimulator/stored_node.c

@@ -186,14 +186,10 @@ int main(int argc, char *argv[]) {
     serviceSock=client_start(argv[2],atoi(argv[3]));
   }
 
-  uint64_t typeStamp=ENB_MAGICDL;
   bool raw = false;
 
   if ( argc == 5 ) {
     raw=true;
-
-    if (strcmp(argv[4],"UL") == 0 )
-      typeStamp=UE_MAGICDL;
   }
 
   samplesBlockHeader_t header;
@@ -213,7 +209,6 @@ int main(int argc, char *argv[]) {
     setblocking(serviceSock, blocking);
 
     if ( raw ) {
-      header.magic=typeStamp;
       header.size=blockSize;
       header.nbAnt=1;
       header.timestamp=timestamp;