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POCPU Usage goes to 100% when running few threads
 

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  1. POCPU Usage goes to 100% when running few threads
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    <p>My code is a UDP single Server/multiple Client application using WSAWaitforMultipleEvents().</p> <p>On the Server side, there are 3 ReceiveThreads and each Receive Thread has its own sendThread. There are three Clients. all this running on the same machine.</p> <p>The code of ReceiveThread is inside While(1). The Client also keeps on sending the data in a while(1) loop. </p> <p>Receive Thread only keeps on receiving a buffer and keeps writing the buffer to a text file.</p> <p>If EOF or EXIT is received, the receivethread should terminate itself and its SendThread as well. </p> <p>Send Thread on the other hand only keeps on reading from another text file and keeps sending the data read from the text file over the socket.</p> <p>The problem that I am facing is that CPU usage exceeds upto 100% when I run this code.</p> <p>Is it due to the fact that all the three threads of the Server are running in While(1) and all the Clients are also reading from the text file and sending data over the socket in while(1)?</p> <p>I've been trying to find out the reason for this 100% CPU Usage since long but havn't figured out anything yet except while(1).</p> <p><strong>EDIT:</strong></p> <p>The code is so long but I am adding it if anyone wants to see it.</p> <pre><code> DWORD WINAPI sendAllThreadProcedure(LPVOID param) { threadDetailStruct* myDetailStruct = (threadDetailStruct*) (param); int threadNumber,portNumber; char *ipNumber; SOCKADDR_IN sendSocket = myDetailStruct-&gt;cliSock; SOCKET sendSocketIdentifier = myDetailStruct-&gt;cliSockIdentifier; threadNumber = myDetailStruct-&gt;threadNum; char clientPort[32],*clientIP = inet_ntoa(sendSocket.sin_addr); int cliPort = ntohs(sendSocket.sin_port); itoa(cliPort,clientPort,10); //======================================================================= int clientSocketLength = sizeof(SOCKADDR_IN); char receiveBuffer[10000]; int recv_len=0; //======================================================================= char file[32]="File.txt"; int sendCount=0; FILE *fpSend; while(1) { if(WaitForSingleObject(terminate_thread_event[threadNumber],0) == WAIT_OBJECT_0) { ResetEvent(terminate_thread_event[threadNumber]); break; } if((fpSend = fopen(TEXT(fileName), "r+b")) == NULL) { //"Unable to open the File" continue; } else { char file_buffer[10000]; int bytes_read=0; char new_buffer[1000] = "FILE",send[1000]; if(sendto(sendSocketIdentifier, new_buffer, sizeof(new_buffer), 0, (struct sockaddr *) &amp;sendSocket, sizeof(sendSocket))&lt;0) { //FILE MEssage NOT SENNT!" continue; } else { while(fpSend!=NULL) { if(WaitForSingleObject(terminate_thread_event[threadNumber],0) == WAIT_OBJECT_0) { ResetEvent(terminate_thread_event[threadNumber]); closesocket(sendSocketIdentifier); fclose(fpSend); return 0; } if((bytes_read=fread(file_buffer, sizeof(char), 5, fpSend))&lt;=0) { if(feof(fpSend)) { char new_buffer[1000] = "EOF",send[1000],exit_message[12]; if(sendto(sendSocketIdentifier, new_buffer, sizeof(new_buffer), 0, (struct sockaddr *) &amp;sendSocket, sizeof(sendSocket))&lt;0) { //"EOF NOT SENNT!" break; } fclose(fpSend); break; } else { /*Unable to copy file into buffer*/ fclose(fpSend); break; } } else { if(sendto(sendSocketIdentifier, file_buffer, bytes_read, 0, (struct sockaddr *) &amp;sendSocket, sizeof(sendSocket))&lt;0) { //"Bytes read from File NOT SENT!" fclose(fpSend); break; } else { sendCount = sendCount+1; } } } } Sleep(100); closesocket(sendSocketIdentifier); return 0; } // ==================== // RECEIVE Thread DWORD WINAPI newrecvThreadProcedure(LPVOID param) { newRecvThreadDetailStruct* myDetailStruct = (newRecvThreadDetailStruct*) (param); char newDetail[256], threadNumber_char[12], ipNumber[32], *detail = myDetailStruct&gt;newsocketDetail; int portNumber,threadNumber_int = myDetailStruct-&gt;threadNum; sscanf(detail,"%s %d",ipNumber,&amp;portNumber); itoa(threadNumber_int,threadNumber_char,10); strcpy(newDetail,threadNumber_char); strcat(newDetail," "); strcat(newDetail,detail); struct node *cur, *newNode; EnterCriticalSection(&amp;cs); cur =cread(); cur-&gt;data = newDetail; cur-&gt;n=NULL; push(cur); newNode = pop(); MessageBox( NULL,"PUSH DONE!","PUSH!",MB_ICONEXCLAMATION | MB_OK); if (ResetEvent(data_available_event) == 0) // signal sender thread that data is available { MessageBox( NULL,"RESET Event is not Set","Failed!",MB_ICONEXCLAMATION | MB_OK); } LeaveCriticalSection(&amp;cs); char file[64] = client.txt; //==================================================================== // Creating New Socket Now WSADATA wsa; //Initialise winsock// if (WSAStartup(MAKEWORD(2,2),&amp;wsa) != 0) { char err[128]; itoa(WSAGetLastError(),err,10); MessageBox( NULL, err, "WinSock Initialization FAILED", MB_ICONINFORMATION); exit(EXIT_FAILURE); } //Create a socket// SOCKET newSocketIdentifier; SOCKADDR_IN newSocket; if((newSocketIdentifier = socket(AF_INET , SOCK_DGRAM , 0 )) == INVALID_SOCKET) { // "Socket Creation Failed", exit(EXIT_FAILURE); } //Socket Created// //Prepare the sockaddr_in structure// newSocket.sin_family = AF_INET; newSocket.sin_addr.s_addr = INADDR_ANY; newSocket.sin_port = htons(portNumber); //Bind// if( bind(newSocketIdentifier ,(struct sockaddr *)&amp;newSocket, sizeof(SOCKADDR_IN)) == SOCKET_ERROR) { //"BIND FAILED inside Thread" } //Bind Done// int waitRet; WSAEVENT hEvent = WSACreateEvent(); WSANETWORKEVENTS events; WSAEventSelect(newSocketIdentifier, hEvent, FD_READ | FD_WRITE); SOCKADDR_IN clientSocket; int clientSocketLength = sizeof(SOCKADDR_IN); char receiveBuffer[3000]={0}; int recv_len = 0,receiveCount = 0; while(1) { waitRet = WSAWaitForMultipleEvents(1, &amp;hEvent, FALSE, INFINITE, FALSE); //WSAResetEvent(hEvent); if(WSAEnumNetworkEvents(newSocketIdentifier,hEvent,&amp;events) == SOCKET_ERROR) { //"FAILURE" continue; } else { //else event occurred starts if(events.lNetworkEvents &amp; FD_READ) { if((recv_len = recvfrom(newSocketIdentifier, receiveBuffer, sizeof(receiveBuffer), 0, (struct sockaddr *) &amp;clientSocket, &amp;clientSocketLength)) == SOCKET_ERROR) { continue; } else { if(memcmp(receiveBuffer,"NewSocket",9) == 0) { if(sendto(newSocketIdentifier, "NewSocket ACK", sizeof("NewSocket ACK"), 0, (struct sockaddr *) &amp;clientSocket, sizeof(clientSocket))&lt;0) { //"NewSocket ACK not SENNT!",err,MB_ICONEXCLAMATION | MB_OK); continue; } else { break; } } } } } } threadDetailStruct threadDetail; threadDetail.cliSock = clientSocket; threadDetail.cliSockIdentifier = newSocketIdentifier; threadDetail.threadNum = threadNumber_int; AHN_glb_sendAllThreadHandle[threadNumber_int] = CreateThread( NULL, 0, sendAllThreadProcedure, (LPVOID)&amp;threadDetail, 0, &amp;idThread[threadNumber_int] ); while(1) { waitRet = WSAWaitForMultipleEvents(1, &amp;hEvent, FALSE, INFINITE, FALSE); //WSAResetEvent(hEvent); if(WSAEnumNetworkEvents(newSocketIdentifier,hEvent,&amp;events) == SOCKET_ERROR) { // "FAILURE" continue; } else { //else event occurred starts if(events.lNetworkEvents &amp; FD_READ) { //check for network event starts //FD_READ if((recv_len = recvfrom(newSocketIdentifier, receiveBuffer, sizeof(receiveBuffer), 0, (struct sockaddr *) &amp;clientSocket, &amp;clientSocketLength)) == SOCKET_ERROR) { //"after FD READ Could not Receive Data" continue; } if(memcmp(receiveBuffer,"EXIT",4) == 0) { SetEvent(terminate_thread_event[threadNumber_int]); } if(memcmp(receiveBuffer,"FILE",4) == 0) { FILE *fprecv = fopen(TEXT(file),"wb"); while(1) { waitRet = WSAWaitForMultipleEvents(1, &amp;hEvent, FALSE, 0, FALSE); if(WSAEnumNetworkEvents(newSocketIdentifier,hEvent,&amp;events) == SOCKET_ERROR) { fclose(fprecv); break; } else { if(events.lNetworkEvents &amp; FD_READ)//else event occurred starts { if((recv_len = recvfrom(newSocketIdentifier, receiveBuffer, sizeof(receiveBuffer), 0, (struct sockaddr *) &amp;clientSocket, &amp;clientSocketLength)) == SOCKET_ERROR) { MessageBox( NULL,"error","Data Reception Failed",MB_ICONINFORMATION); fclose(fprecv); exit(EXIT_FAILURE); break; } receiveCount = recv_len+receiveCount; if(memcmp(receiveBuffer,"EXIT",4) == 0) { SetEvent(terminate_thread_event[threadNumber_int]); fclose(fprecv); return 0; } if(memcmp(receiveBuffer,"EOF",3) == 0) { fclose(fprecv); break; } if(memcmp(receiveBuffer,"FILE",4) == 0) { fclose(fprecv); remove(TEXT(file)); fprecv = fopen(TEXT(file),"wb"); continue; } **if(fwrite(receiveBuffer, 1, recv_len, fprecv)&lt;0) { MessageBox( NULL,"problem while writing file","Error!",MB_ICONINFORMATION); fclose(fprecv); break; }** } //if FD_READ }// else network event receievd ENDS }// While(1) for receiveing File Ends FILE *fp1 ; if((fp1 = fopen(TEXT(file), "rb")) == NULL) { MessageBox( NULL,"Unable to open the File","Error!",MB_ICONEXCLAMATION |MB_OK); break; } char filecmp[1000]; strcpy(filecmp,"Client"); strcat(filecmp,threadNumber_char); strcat(filecmp,"Original"); strcat(filecmp,".txt"); FILE *fp2 ; if((fp2 = fopen(TEXT(filecmp), "rb")) == NULL) { MessageBox( NULL,"Unable to open the Original File","Error!",MB_ICONEXCLAMATION | MB_OK); break; } int ch1 = getc( fp1 ) ; int ch2 = getc( fp2 ) ; while( (ch1!=EOF) &amp;&amp; (ch2!=EOF) &amp;&amp; (ch1 == ch2)) { ch1 = getc(fp1); ch2 = getc(fp2) ; } char display[3000]; strcpy(display,file); strcat(display," Received and "); strcat(display,filecmp); int idx=GetWindowTextLength(AHN_glb_resultWindowHandle); SendMessage(AHN_glb_resultWindowHandle,EM_SETSEL,idx,idx); SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)"\r\n"); if (ch1 != ch2) { SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)"\r\n"); SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)" "); SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)TEXT(display)); SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)" are Not Identical"); } else if (ch1 == ch2) { SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)"\r\n"); SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)" "); SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)TEXT(display)); SendMessage(AHN_glb_resultWindowHandle,EM_REPLACESEL,0,(LPARAM)" are Identical"); } fclose ( fp1 ); fclose ( fp2 ); } //if memecmp == FILE ENDS } //if FD_READ ENDS }// else if event occurred ENDS }//while(1) ENDS return 0; } // =============================================================================================================== </code></pre>
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    1. This table or related slice is empty.
    1. PTQuestion
    1. USAyse
    1. USAyse
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. PTAnswer
    1. VO
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      1. POCPU Usage goes to 100% when running few threads
      1. This table or related slice is empty.
      1. VTDownMod
    2. VO
      singulars
      1. POCPU Usage goes to 100% when running few threads
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POCPU Usage goes to 100% when running few threads
      1. This table or related slice is empty.
      1. VTDownMod
    1. COThe real question is, what does your code do when it doesn't have any real work? If it spins in your while loop, then you're going to chew up all the CPU.
      singulars
      1. POCPU Usage goes to 100% when running few threads
      1. UShatchet
    2. COWe need to see actual code to be able to diagnose the problem. Just of the top of my head: are you using non-blocking functions for sending or receiving data? If so, you might be occupying the CPU with what is essentially a busy wait where the threads could be sleeping until arrival of data instead.
      singulars
      1. POCPU Usage goes to 100% when running few threads
      1. USidoby
 

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