MQTT併發測試（Linux嵌入式環境）

發佈者代碼：

#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; //線程ID
	int iTestCnt; //測試次數
}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);

	//用戶ID，每個發佈消息的客戶端都不一樣！
	memset(szClientId, 0, sizeof(szClientId));
	sprintf(szClientId, "%c", pThrdPara->iThrdId);

	//待發布的負載數據，通過線程號來區分
	memset(payload, 0, sizeof(payload));
	sprintf(payload, "hello world! thrd-%d", pThrdPara->iThrdId);
	printf("payload: %s\n", payload);

	//創建MQTT客戶端，綁定服務器地址、客戶端ID
//    MQTTClient_create(&client, ADDRESS, CLIENTID,
	  MQTTClient_create(&client, ADDRESS, szClientId,
        MQTTCLIENT_PERSISTENCE_NONE, NULL);
    conn_opts.keepAliveInterval = 20;
    conn_opts.cleansession = 1;

	//connect服務端
    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)
	{
		//發佈消息
	    //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);

		//等待消息發佈完成
	    rc = MQTTClient_waitForCompletion(client, token, TIMEOUT);
	    //printf("Message with delivery token %d delivered\n", token);
		//printf("--------------------iCnt=%d----------------------\n", iCnt);
	}
	//計算消息發佈所有的時間，單位微妙
	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：主函數
//參數：@argc argv參數個數
//		@argv:
//				argv[1] 線程個數
//				argv[2] 單個線程通信的次數
//Example: ./MQTTClient_publish 3 100 
//			其中3表示運行3個線程,100表示每個線程發佈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);
	}

	//通過主函數的參數控制創建線程的個數、每個線程下的消息發佈條數
	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<iThrdNum; iThrdIdx++)
	{
		pThrdPara[iThrdIdx].iThrdId = iThrdIdx;
		pThrdPara[iThrdIdx].iTestCnt = iTestNum;
		pthread_create(&pthrd[iThrdIdx], NULL, &main_thread, (void *)&pThrdPara[iThrdIdx]);
//		sleep(5);
	}

	do  
	{ 
		ch = getchar(); 
	} while(ch!='Q' && ch != 'q'); 


	return NULL;
}

訂閱者代碼：

#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: ");  

	//按照我們的需求，需要在payload負載數據中攜帶對應數據的屬性
	payloadptr = message->payload; 
	for(i=0; i<message->payloadlen; 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; 

	//創建MQTT訂閱客戶端，綁定服務端地址、以及當前訂閱者的用戶ID（每個客戶端的用戶ID務必保證唯一性）
	MQTTClient_create(&client, ADDRESS, CLIENTID, 
	MQTTCLIENT_PERSISTENCE_NONE, NULL); 
	conn_opts.keepAliveInterval = 20; 
	conn_opts.cleansession = 1; 

	//綁定MQTT訂閱者客戶端的消息到達、消息發送的回調函數 
	MQTTClient_setCallbacks(client, NULL, connlost, msgarrvd, delivered); 
	 
	//MQTT訂閱者客戶端連接服務端 
	if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS) 
	{ 
		printf("Failed to connect, return code %d\n", rc); 
		exit(EXIT_FAILURE); 
	} 

	//提交訂閱者給服務端
	printf("Subscribing to topic %s\nfor client %s using QoS%d\n\n" 
		"Press Q<Enter> 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

 

方案驗證結果：由於發佈者和訂閱者的消息是同步的，以下消耗時間均指發佈者和訂閱者的時間；

驗證方案1
進程	發送次數	發送消耗時間（us）
發佈者進程1	100	10998389
發佈者進程1	200	21997781
發佈者進程1	500	55018353

結論：同一個進程發送100、200、500次所耗時間，平均每次發送時間爲100ms；

驗證方案2
進程	發送次數	發送消耗時間（us）
發佈者進程1	100	10997878
發佈者進程2	100	10999326
發佈者進程1	200	22017567
發佈者進程2	200	21997405
發佈者進程1	500	54998293
發佈者進程2	500	55007166

結論：不同進程同時發送100、200、500次所耗時間，平均每次發送時間爲100ms；

總結：綜合方案1和方案2，多個進程與單個進程的負載通信所耗時間相同，所以單個進程或多個進程對MQTT服務器的負載沒有影響，但每次發佈一次負載消息所耗時間爲100ms，系統庫無法用這種通信機制滿足；