simple_source模块可以在外部设置的属性




有四个局部统计量,分别为产生的bit速率、包速率、包大小,包间隔




状态机为三个非强制对象,在头文件里定义了自中断和转移条件。

/*Include files.                                              */

#include   <oms_dist_support.h>

/*Special  attribute  values.                 */ 

#define              SSC_INFINITE_TIME                  -1.0

 

/*Interrupt  code  values.                     */       自定义中断

#define              SSC_START                                   0

#define              SSC_GENERATE                           1

#define              SSC_STOP                                     2

/* Nodeconfiguration constants.   */

#define              SSC_STRM_TO_LOW                          0

 

/* Macrodefinitions for state          */

/*transitions.                                                */定义转移条件

#define              START                                   (intrpt_code == SSC_START)

#define              DISABLED                            (intrpt_code == SSC_STOP)

#define              STOP                                     (intrpt_code == SSC_STOP)

#define              PACKET_GENERATE                   (intrpt_code == SSC_GENERATE)

 

/*Function prototypes.                               */

staticvoid                           ss_packet_generate(void);

 

 

 

 

 

Init非强制状态的入口程序为

/* Atthis initial state, we read the values of source attributes     */包含源的属性定义

/* andschedule a selt interrupt that will indicate our start time   */表明开始的时间

/* forpacket generation.                                                                                                      */

 

/* Obtainthe object id of the surrounding module.                                              */

own_id = op_id_self ();获得所属处理器或队列的对象ID

 

/* Readthe values of the packet generation parameters, i.e. the         */

/*attribute values of the surrounding module.                                  */获取给定对象的某属性

op_ima_obj_attr_get (own_id,"Packet Interarrival Time", interarrival_str);包间隔

op_ima_obj_attr_get(own_id, "Packet Size",             size_str);   包大小

op_ima_obj_attr_get(own_id, "Packet Format",           format_str);包格式

op_ima_obj_attr_get(own_id, "Start Time",              &start_time);开始时间

op_ima_obj_attr_get(own_id, "Stop Time",               &stop_time);停止时间

 

/* Loadthe PDFs that will be used in computing the packet                     */

/*interarrival times and packet sizes.                                */PDF中加载分布

interarrival_dist_ptr= oms_dist_load_from_string (interarrival_str);

pksize_dist_ptr       = oms_dist_load_from_string (size_str);

 

/* Verifythe existence of the packet format to be used for                      */

/*generated packets.                                                    */

if(strcmp (format_str, "NONE") == 0)  检查是否为无格式的包

         {

         /* We will generate unformattedpackets. Set the flag.                            */

         generate_unformatted = OPC_TRUE;

         }

else

         {

         /* We will generate formatted packets.Turn off the flag.               */

         generate_unformatted = OPC_FALSE;

 

         /* Get the list of all available packetformats.*/函数返回一系列包格式的名字

         pk_format_names_lptr =prg_tfile_name_list_get (PrgC_Tfile_Type_Packet_Format);

 

         /* Search the list for the requestedpacket format.*/查找所需要的包格式

         format_found = OPC_FALSE;

         for (i = prg_list_size(pk_format_names_lptr); ((format_found == OPC_FALSE) && (i > 0));i--)

                   {

                   /* Access the next formatname and compare with requested    */

                   /* format name.                                                                                                             */

                   found_format_str = (char *)prg_list_access (pk_format_names_lptr, i - 1);

                   if (strcmp (found_format_str,format_str) == 0)

                            format_found =OPC_TRUE;找到了所需要的包格式

                   }

 

    if (format_found == OPC_FALSE)

                   {

                   /* The requested format doesnot exist. Generate                          */

                   /* unformatted packets.                                                                                     */

                   generate_unformatted =OPC_TRUE;

        

                   /* Display an appropriatewarning.*/没有找到需要的包格式,输出警告

                   op_prg_odb_print_major("Warning from simple packet generator model (simple_source):",

                                                                           "Thespecified packet format", format_str,

                                                                           "isnot found. Generating unformatted packets instead.", OPC_NIL);

                   }

 

         /* Destroy the lits and its elementssince we don't need it    */

         /* anymore.                                                                                                                              */

         prg_list_free(pk_format_names_lptr);释放内存

         prg_mem_free  (pk_format_names_lptr);

         }       

 

          

/* Makesure we have valid start and stop times, i.e. stop time is         */

/* notearlier than start time.          */

if((stop_time <= start_time) && (stop_time != SSC_INFINITE_TIME))

         {如果结束时间早于开始时间或结束时间不为无穷

         /* Stop time is earlier than starttime. Disable the source.   */

         start_time = SSC_INFINITE_TIME;  设置开始时间为无穷并且输出警告

         /* Display an appropriate warning.                                                                           */

         op_prg_odb_print_major ("Warningfrom simple packet generator model (simple_source):",

                                                                 "Althoughthe generator is not disabled (start time is set to a finite value),",

                                                                 "astop time that is not later than the start time is specified.",

                                                                 "Disablingthe generator.", OPC_NIL);

         }

 

/*Schedule a self interrupt that will indicate our start time for     */

/* packetgeneration activities. If the source is disabled,                         */

/*schedule it at current time with the appropriate code value.             */

if(start_time == SSC_INFINITE_TIME) 如果开始时间是无穷,安排自中断开始时间为仿真时间,否则为实际开始时间

         {

         op_intrpt_schedule_self (op_sim_time(), SSC_STOP);

         }

else

         {

         op_intrpt_schedule_self (start_time, SSC_START);

 

         /* In this case, also schedule theinterrupt when we will stop       */

         /* generating packets, unless we areconfigured to run until         */

         /* the end of the simulation.   */   仿真结束时间安排一个自中断

         if (stop_time != SSC_INFINITE_TIME)

                   {

                   op_intrpt_schedule_self(stop_time,SSC_STOP);

                   }

        

         next_intarr_time = oms_dist_outcome(interarrival_dist_ptr);通过一个分布生成一个浮点数

 

         /* Make sure that interarrival time isnot negative. In that case it */

         /* will be set to 0.    */确认间隔时间不为负,否则设为0

         if (next_intarr_time <0)

                   {

                   next_intarr_time = 0.0;

                   }

 

         }

 

/*Register the statistics that will be maintained by this model.   */声明局部统计量

bits_sent_hndl            =op_stat_reg ("Generator.Traffic Sent (bits/sec)",                           OPC_STAT_INDEX_NONE,OPC_STAT_LOCAL);

packets_sent_hndl   = op_stat_reg ("Generator.Traffic Sent(packets/sec)",              OPC_STAT_INDEX_NONE,OPC_STAT_LOCAL);

packet_size_hndl    = op_stat_reg ("Generator.Packet Size(bits)",             OPC_STAT_INDEX_NONE, OPC_STAT_LOCAL);

interarrivals_hndl  = op_stat_reg ("Generator.PacketInterarrival Time (secs)", OPC_STAT_INDEX_NONE, OPC_STAT_LOCAL);

 

 

init出口程序

 

/*Determine the code of the interrupt, which is used in evaluating      */

/* statetransition conditions.         */

intrpt_code= op_intrpt_code ();

 

 

init转到generate状态时的执行的函数代码

staticvoid

ss_packet_generate(void)

         {

         Packet*                                pkptr;

         double                                  pksize;

 

         /** This function creates a packetbased on the packet generation**/

         /** specifications of the source modeland sends it to the lower layer.**/

         FIN (ss_packet_generate ());

 

         /* Generate a packet size outcome.                                             */

         pksize = (double) ceil(oms_dist_outcome (pksize_dist_ptr));

         ceil返回大于或等于指定表达式的最小整数

         /* Create a packet of specified formatand size.*/

         if (generate_unformatted == OPC_TRUE)

                   {

                   /* We produce unformattedpackets. Create one. */

                   pkptr = op_pk_create(pksize);

                   }

         else

                   {

                   /* Create a packet with the specifiedformat.*/

                   pkptr = op_pk_create_fmt(format_str);创建一个预定义结构的包,返回包格式

                   op_pk_total_size_set (pkptr,pksize);  设置包的大小

                   }

 

         /* Update the packet generationstatistics.   */

         op_stat_write (packets_sent_hndl, 1.0);

         op_stat_write (packets_sent_hndl, 0.0);

         op_stat_write (bits_sent_hndl, (double)pksize);

         op_stat_write (bits_sent_hndl, 0.0);

         op_stat_write (packet_size_hndl,(double) pksize);

         op_stat_write (interarrivals_hndl,next_intarr_time);

 

         /* Send the packet via the stream tothe lower layer.    */

         op_pk_send (pkptr, SSC_STRM_TO_LOW);将包发送到输出包流中

 

         FOUT;

         }       

 

 

 

 

generate状态的入口代码

/* At theenter execs of the "generate" state we schedule the              */

/*arrival of the next packet.                                                                                       */

next_intarr_time= oms_dist_outcome (interarrival_dist_ptr);

 

/* Makesure that interarrival time is not negative. In that case it */

/* will beset to 0. */  确定包生成的间隔时间是有效的

if(next_intarr_time <0)

         {

         next_intarr_time = 0;

         }

 

next_pk_evh= op_intrpt_schedule_self (op_sim_time () + next_intarr_time, SSC_GENERATE);

 

generate的出口代码

/*Determine the code of the interrupt, which is used in evaluating      */

/* statetransition conditions.                                                                                             */

intrpt_code= op_intrpt_code ();

 

stop状态的入口代码

/* Whenwe enter into the "stop" state, it is the time for us to     */

/* stopgenerating traffic. We simply cancel the generation of the        */

/* nextpacket and go into a silent mode by not scheduling anything    */

/* else.                                                                                                                                       */

if(op_ev_valid (next_pk_evh) == OPC_TRUE)

         {

         op_ev_cancel (next_pk_evh);  撤销事件

         }


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