MQTT并发测试（Linux嵌入式环境）

发布者代码：

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "MQTTClient.h"

#define ADDRESS     "tcp://localhost:1883"
#define CLIENTID    "ExampleClientPub"
#define TOPIC       "MQTT Examples"
#define PAYLOAD     "Hello World!"
#define QOS         1
#define TIMEOUT     10000L


int GetSec(void)
{
	struct timeval tv;

	gettimeofday(&tv,NULL);

	//printf("GetSec: sec=%d, usec=%d\n", tv.tv_sec, tv.tv_usec);

	//printf("start sec=%ld, mill_sec=%ld, micr_sec=%ld\n", \
	//	tvBef.tv_sec, tvBef.tv_sec*1000 + tvBef.tv_usec/1000, tvBef.tv_sec*1000000 + tvBef.tv_usec);	

	return tv.tv_sec;

}

int GetMillSec(void)
{
	struct timeval tv;

	gettimeofday(&tv,NULL);

	//printf("GetMillSec: sec=%d, usec=%d\n", tv.tv_sec, tv.tv_usec);

	//printf("start sec=%ld, mill_sec=%ld, micr_sec=%ld\n", \
	//	tvBef.tv_sec, tvBef.tv_sec*1000 + tvBef.tv_usec/1000, tvBef.tv_sec*1000000 + tvBef.tv_usec);	

	return tv.tv_sec*1000 + tv.tv_usec/1000;
}

int GetMirc(void)
{
	struct timeval tv;

	gettimeofday(&tv,NULL);

	//printf("GetMirc: sec=%d, usec=%d\n", tv.tv_sec, tv.tv_usec);

	//printf("start sec=%ld, mill_sec=%ld, micr_sec=%ld\n", \
	//	tvBef.tv_sec, tvBef.tv_sec*1000 + tvBef.tv_usec/1000, tvBef.tv_sec*1000000 + tvBef.tv_usec);	

	return tv.tv_sec*1000000 + tv.tv_usec;

}

typedef struct{
	int iThrdId; //线程ID
	int iTestCnt; //测试次数
}ThrdPara;

int main_thread(void* argv)
{
    MQTTClient client;
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    MQTTClient_message pubmsg = MQTTClient_message_initializer;
    MQTTClient_deliveryToken token;
    int rc, iCnt;
	int iBf, iAf;
	char szClientId[32];
	char payload[128];
	ThrdPara *pThrdPara;


	pThrdPara = (ThrdPara*)argv;
	printf("main_thread: pThrdPara->iThrdId=%d, pThrdPara->iTestCnt=%d.\n", pThrdPara->iThrdId, pThrdPara->iTestCnt);

	//用户ID，每个发布消息的客户端都不一样！
	memset(szClientId, 0, sizeof(szClientId));
	sprintf(szClientId, "%c", pThrdPara->iThrdId);

	//待发布的负载数据，通过线程号来区分
	memset(payload, 0, sizeof(payload));
	sprintf(payload, "hello world! thrd-%d", pThrdPara->iThrdId);
	printf("payload: %s\n", payload);

	//创建MQTT客户端，绑定服务器地址、客户端ID
//    MQTTClient_create(&client, ADDRESS, CLIENTID,
	  MQTTClient_create(&client, ADDRESS, szClientId,
        MQTTCLIENT_PERSISTENCE_NONE, NULL);
    conn_opts.keepAliveInterval = 20;
    conn_opts.cleansession = 1;

	//connect服务端
    if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS)
    {
        printf("Failed to connect, return code %d\n", rc);
        exit(EXIT_FAILURE);
    }
	iCnt = 0;
	printf("--------------------pThrdPara->iThrdId=%d, iCnt=%d----------------------\n", pThrdPara->iThrdId, pThrdPara->iTestCnt);
	iBf = GetMirc();
	while (iCnt++ < pThrdPara->iTestCnt)
	{
		//发布消息
	    //pubmsg.payload = PAYLOAD;
	    //pubmsg.payloadlen = strlen(PAYLOAD);
	    pubmsg.payload = payload;
		pubmsg.payloadlen = strlen(payload);
	    pubmsg.qos = QOS;
	    pubmsg.retained = 0;
	    MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token);
	    //printf("Waiting for up to %d seconds for publication of %s\n"
	    //        "on topic %s for client with ClientID: %s\n",
	    //        (int)(TIMEOUT/1000), PAYLOAD, TOPIC, CLIENTID);

		//等待消息发布完成
	    rc = MQTTClient_waitForCompletion(client, token, TIMEOUT);
	    //printf("Message with delivery token %d delivered\n", token);
		//printf("--------------------iCnt=%d----------------------\n", iCnt);
	}
	//计算消息发布所有的时间，单位微妙
	iAf = GetMirc();
	printf("thrd-%d, Interv time MircSec=%d.\n", pThrdPara->iThrdId, iAf-iBf);

    MQTTClient_disconnect(client, 10000);
    MQTTClient_destroy(&client);
    return rc;
}

//描述：主函数
//参数：@argc argv参数个数
//		@argv:
//				argv[1] 线程个数
//				argv[2] 单个线程通信的次数
//Example: ./MQTTClient_publish 3 100 
//			其中3表示运行3个线程,100表示每个线程发布100次消息
int main(int argc, char *argv[])
{
	ThrdPara *pThrdPara;
	pthread_t *pthrd;
	int iThrdNum;
	int iTestNum;
	int iThrdIdx;
	char szTestNumStr[16];
	char ch;

	if (argc != 3)
	{

		printf("main: Failed to argc, argc=%d\n", argc);
		exit(0);
	}

	//通过主函数的参数控制创建线程的个数、每个线程下的消息发布条数
	iThrdNum = atoi(argv[1]);
	iTestNum = atoi(argv[2]);
	printf("main: iThrdNum=%d, iTestNum=%d\n", iThrdNum, iTestNum);
	pthrd = malloc(sizeof(pthread_t)*iThrdNum);
	pThrdPara = malloc(sizeof(ThrdPara)*iThrdNum);
	for (iThrdIdx=0; iThrdIdx

订阅者代码：

#include "stdio.h" 
#include "stdlib.h" 
#include "string.h" 
#include "MQTTClient.h" 

 
#define ADDRESS     "tcp://localhost:1883" 
#define CLIENTID    "ExampleClientSub" 
#define TOPIC       "MQTT Examples" 
#define PAYLOAD     "Hello World!" 
#define QOS         1 
#define TIMEOUT     10000L 

 
volatile MQTTClient_deliveryToken deliveredtoken; 

 
void delivered(void *context, MQTTClient_deliveryToken dt) 
{ 
    printf("Message with token value %d delivery confirmed\n", dt); 
    deliveredtoken = dt; 
} 
 
int msgarrvd(void *context, char *topicName, int topicLen, MQTTClient_message *message) 
{ 
	int i; 
	char* payloadptr; 
 
	printf("Message arrived\n"); 
	printf("     topic: %s\n", topicName); 
	printf("   message: ");  

	//按照我们的需求，需要在payload负载数据中携带对应数据的属性
	payloadptr = message->payload; 
	for(i=0; ipayloadlen; i++) 
	{ 
		putchar(*payloadptr++); 
	} 
	putchar('\n'); 
	MQTTClient_freeMessage(&message); 
	MQTTClient_free(topicName); 
	return 1; 
} 
 
void connlost(void *context, char *cause) 
{ 
	printf("\nConnection lost\n"); 
	printf("     cause: %s\n", cause); 
} 

int main(int argc, char* argv[]) 
{ 
	MQTTClient client; 
	MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer; 
	int rc; 
	int ch; 

	//创建MQTT订阅客户端，绑定服务端地址、以及当前订阅者的用户ID（每个客户端的用户ID务必保证唯一性）
	MQTTClient_create(&client, ADDRESS, CLIENTID, 
	MQTTCLIENT_PERSISTENCE_NONE, NULL); 
	conn_opts.keepAliveInterval = 20; 
	conn_opts.cleansession = 1; 

	//绑定MQTT订阅者客户端的消息到达、消息发送的回调函数 
	MQTTClient_setCallbacks(client, NULL, connlost, msgarrvd, delivered); 
	 
	//MQTT订阅者客户端连接服务端 
	if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) 
	{ 
		printf("Failed to connect, return code %d\n", rc); 
		exit(EXIT_FAILURE); 
	} 

	//提交订阅者给服务端
	printf("Subscribing to topic %s\nfor client %s using QoS%d\n\n" 
		"Press Q to quit\n\n", TOPIC, CLIENTID, QOS); 
	MQTTClient_subscribe(client, TOPIC, QOS); 

	 
	do  
	{ 
		ch = getchar(); 
	} while(ch!='Q' && ch != 'q'); 
	 
	 
	MQTTClient_disconnect(client, 10000); 
	MQTTClient_destroy(&client); 
	return rc; 
} 

makfile：

arm-linux-gnueabi-gcc MQTTClient_publish.c -o MQTTClient_publish -L./linux_mqtt_c -lpaho-mqtt3c -lpthread

arm-linux-gnueabi-gcc MQTTClient_subscribe.c -o MQTTClient_subscribe -L./linux_mqtt_c -lpaho-mqtt3c -lpthread

 

方案验证结果：由于发布者和订阅者的消息是同步的，以下消耗时间均指发布者和订阅者的时间；

验证方案1
进程	发送次数	发送消耗时间（us）
发布者进程1	100	10998389
发布者进程1	200	21997781
发布者进程1	500	55018353

结论：同一个进程发送100、200、500次所耗时间，平均每次发送时间为100ms；

验证方案2
进程	发送次数	发送消耗时间（us）
发布者进程1	100	10997878
发布者进程2	100	10999326
发布者进程1	200	22017567
发布者进程2	200	21997405
发布者进程1	500	54998293
发布者进程2	500	55007166

结论：不同进程同时发送100、200、500次所耗时间，平均每次发送时间为100ms；

总结：综合方案1和方案2，多个进程与单个进程的负载通信所耗时间相同，所以单个进程或多个进程对MQTT服务器的负载没有影响，但每次发布一次负载消息所耗时间为100ms，系统库无法用这种通信机制满足；