問題:他の質問の 1 つと同様に 、C でプログラムを作成しようとしています。このプログラムを使用すると、可変量のスレッドを使用して 10 個のテキスト ファイルを検索し、最大のプライムを見つけることができます。また、ワーカー スレッドの最大プライム数を読み取ることができる (変更しない) マネージャー スレッドも必要です。マネージャー スレッドは、ワーカー スレッドがそれを読み取って使用できるように、すべてのワーカー スレッドによって検出された最大の素数もポストします。ワーカー スレッドは、ローカルの Largest Prime をグローバル配列 (privateLargestPrime) にポストする必要があります。これを行う前に、ワーカー スレッドが更新するまでマネージャー スレッドがそれを読み取らないようにロックする必要があります。
奇妙な部分：ワーカースレッドがロックを呼び出したいときにプログラムをステップ実行すると、スレッドがロックを呼び出してロックが付与されたマネージャーに切り替わり、ワーカースレッドを飢えさせてループし続けます。私はそれで何が起こっているのか分かりません。この問題について何らかの洞察を得ることができれば、それは大歓迎です。
/*
* The Reason for Worker Initialization + Manager Initialization is that we need both types of threads to exist at the same time
* so I just combined them into one loop, although I believe that they could have been created seperatly.
* Basically just call pthread_Join at the end
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <pthread.h>
#include <time.h>
#include <string.h>
#include <fileTest.h>
clock_t Start, End;
double elapsed = 0;
pthread_cond_t managerVar;
pthread_mutex_t mutex;
unsigned int globalLargestPrime = 0;
int numThreads = 1;//Number of Threads
int LINES_PER_THREAD;
pthread_cond_t *WorkerConditionaVar;
pthread_cond_t *ManagerConditionaVar;
unsigned int *privateLocalLargest;//will need to be changed
int *statusArray;
FILE *fileOut;
typedef enum{
FREE,
IN_USE
}lrgstPrm;
lrgstPrm monLargestPrime;//create enum
lrgstPrm workerLargestPrime;//create enum
typedef enum{
Finished,
Not_Finished
}Status;
Status is_Finished;
typedef struct threadFields{
int id;
int StartPos;//gets seek for worker thread
int EndPos;
}tField;
int ChkPrim(unsigned int n){
unsigned int i;
unsigned int root = sqrt(n);
for(i=2; i<root; i++){
if(n % i == 0)
return 0;
}
//printf("%d \n", isPrime);
return 1;
}
void *Worker(void *threadStruct){//Create Threads
struct threadFields *info = threadStruct;
int index;
int id = info->id;
unsigned int currentNum = 0;
int Seek = info->StartPos;
unsigned int localLargestPrime = 0;
char *buffer = malloc(50);
int isPrime = 0;
while(Seek<info->EndPos){
for(index = 0; index < 1000; index++){//Loop 1000 times
fseek(fileOut,Seek*sizeof(char)*20, SEEK_SET);
fgets(buffer,20,fileOut);
Seek++;
currentNum = atoi(buffer);
if(currentNum>localLargestPrime && currentNum > 0){
isPrime = ChkPrim(currentNum);
if( isPrime == 1)
localLargestPrime = currentNum;
}
}
//while(monLargestPrime == IN_USE)
//pthread_cond_wait(&monitor[id], &mutex);//wait untill mutex is unlocked
//monLargestPrime = IN_USE;
//Critical Zone
//printf("Entering Critical Zone My ID: %d\n",id);
/*Should Lock the Private Largest Prime from any other thread using it*/
if(pthread_mutex_lock(&mutex) != 0)//Lock
printf("Failed To Lock");
while(workerLargestPrime == IN_USE)//Wait untill Workers largest prime is free
pthread_cond_wait(ManagerConditionaVar, &mutex);
workerLargestPrime = IN_USE;//Local Largest is in use
privateLocalLargest[id] = localLargestPrime;//Assign Local Largest to each workers Shared Variable
workerLargestPrime = FREE;
pthread_cond_signal(ManagerConditionaVar);//Signal to any waiting thread that wants to touch(read) this workers privateLocalLargest
pthread_mutex_unlock(&mutex);
/*
pthread_mutex_lock(&mutex);
while(workerLargestPrime == FREE){
workerLargestPrime = IN_USE;
//pthread_cond_wait(&managerVar,&mutex);
*/
if(localLargestPrime < globalLargestPrime)
localLargestPrime = globalLargestPrime;
/*
workerLargestPrime = FREE;
pthread_mutex_unlock(&mutex);
// for(index = 0; index < numThreads; index++)
// if(index != id)
// pthread_cond_signal(&monitor[id]);//signal all threads that mutex is unlocked
//monLargestPrime = FREE;
//printf("Exiting Critical Zone My ID: %d\n",id);
*/
//pthread_mutex_unlock(&mutex);
}//End of While
statusArray[id] = 1;
void *i = 0;
return i;
}
void *manager(){
int index, MlocalLargestPrime;
while(is_Finished==Not_Finished){
/*Should Lock the Private Largest Prime from any other thread using it*/
if(pthread_mutex_lock(&mutex) != 0)//Lock
printf("Failed To Lock");
while(workerLargestPrime == IN_USE)//Wait untill Workers largest prime is free
pthread_cond_wait(ManagerConditionaVar, &mutex);
workerLargestPrime = IN_USE;//Local Largest is in use
//Critical Zone
for(index =0; index < numThreads; index++)
if(privateLocalLargest[index] > MlocalLargestPrime)
MlocalLargestPrime = privateLocalLargest[index];
//Critical Zone
workerLargestPrime = FREE;
pthread_cond_signal(ManagerConditionaVar);//Signal to any waiting thread that wants to touch(read) this workers privateLocalLargest
pthread_mutex_unlock(&mutex);
/*
pthread_mutex_lock(&mutex);
while(workerLargestPrime == FREE){
workerLargestPrime = IN_USE;
globalLargestPrime = MlocalLargestPrime;
workerLargestPrime = FREE;
pthread_cond_signal(&managerVar);
}
pthread_mutex_unlock(&mutex);
*/
/*check if workers have finished*/
for(index = 0; index < numThreads; index++)
if(statusArray[index] == 0)
is_Finished = Not_Finished;
}
void *i = 0;
return i;
}
int main(){
//setFile();
LINES_PER_THREAD = (getLineNum()/numThreads);
fileOut = fopen("TextFiles/dataBin.txt", "rb");
Start = clock();
//pthread_t managerThread;
pthread_t threads[numThreads];
pthread_cond_t monitor[numThreads];
pthread_cond_t managerCon;
WorkerConditionaVar = monitor;//Global Pointer points to the array created in main
ManagerConditionaVar = &managerCon;
unsigned int WorkerSharedVar[numThreads];
privateLocalLargest = WorkerSharedVar;
pthread_mutex_init(&mutex, NULL);
int finishedArr[numThreads];
statusArray = finishedArr;
is_Finished = Not_Finished;
int index;
/*Worker Initialization + Manager Initialization*/
pthread_cond_init(&managerCon,NULL);
/*Worker Thread Struct Initalization*/
tField *threadFields[numThreads];//sets number of thread structs
rewind(fileOut);
for(index = 0; index < numThreads; index++){//run through threads; inizilize the Struct for workers
pthread_cond_init(&monitor[index], NULL);//Initialize all the conditional variables
threadFields[index] = malloc(sizeof(tField));
threadFields[index]->id = index;
threadFields[index]->StartPos = index*LINES_PER_THREAD;// Get Position for start of block
threadFields[index]->EndPos = (index+1)*LINES_PER_THREAD-1;// Get Position for end of block
}
/*Worker Thread Struct Initalization*/
for(index = 0; index<numThreads+1; index++)
if(index == numThreads)//Last Thread is Manager Thread
pthread_create(&threads[index],NULL,manager,NULL);//Create Manager
else//Worker Threads
pthread_create(&threads[index],NULL,Worker,(void *)threadFields[index]);//Pass struct to each worker
for(index = 0; index<numThreads+1; index++)
pthread_join(threads[index], NULL);
/*Worker Initialization + Manager Initialization*/
/*Destroy the mutexes & conditional signals*/
for(index = 0; index < numThreads; index++){
pthread_cond_destroy(&WorkerConditionaVar[index]);
}
pthread_cond_destroy(&managerCon);
pthread_mutex_destroy(&mutex);
End = clock();
elapsed = ((double) (End - Start)) / CLOCKS_PER_SEC;
printf("This is the Time %f\n", elapsed);
printf("This is the Largest Prime Number: %u", globalLargestPrime);
return 0;
}
[1]: https://stackoverflow.com/questions/13672456/slightly-complicated-thread-synchronization
1 つの方法しか使用しない別の C ソースがあり、10 個のテキスト ファイルから行数を取得するためのものです。これも投稿します (必須ではありません)。
/*
* fileTest.c
*
* Created on: Dec 8, 2012
* Author: kevin
*
* count number of lines
* divide by number of threads
* get the positions to hand to each thread
* to get positions, one needs to get the number of lines per thread,
* add number of lines to each: Seek*sizeof(char)*10, SEEK_SET.
* and hand out these positions to each thread
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <pthread.h>
#include <time.h>
#include <string.h>
FILE *filesIn[10], *fileOut;
int Seek;
void createText(){
FILE *fOUT = fopen("data9.txt", "w");
int i;
srand(time(NULL));
for(i=0; i<10000; i++)
fprintf(fOUT, "%d\n",rand()%9000);
fclose(fOUT);
}
void setFile(){
int index;
Seek = 0;
char *buffer = malloc(50);
filesIn[0] = fopen("TextFiles/primes1.txt", "r");//read Text
filesIn[1] = fopen("TextFiles/primes2.txt", "r");//read Text
filesIn[2] = fopen("TextFiles/primes3.txt", "r");//read Text
filesIn[3] = fopen("TextFiles/primes4.txt", "r");//read Text
filesIn[4] = fopen("TextFiles/primes5.txt", "r");//read Text
filesIn[5] = fopen("TextFiles/primes6.txt", "r");//read Text
filesIn[6] = fopen("TextFiles/primes7.txt", "r");//read Text
filesIn[7] = fopen("TextFiles/primes8.txt", "r");//read Text
filesIn[8] = fopen("TextFiles/primes9.txt", "r");//read Text
filesIn[9] = fopen("TextFiles/primes10.txt", "r");//read Text
fileOut = fopen("TextFiles/dataBin.txt", "wb");//write in bin
for(index = 0; index < 10; index++)//Run through 10 files
while(!feof(filesIn[index])){
fscanf(filesIn[index],"%s", buffer);//take line from input
fseek(fileOut,Seek*sizeof(char)*20, SEEK_SET);
fputs(buffer,fileOut);//Print line to output file
Seek++;
}
fclose(filesIn[0]);
fclose(filesIn[1]);
fclose(filesIn[2]);
fclose(filesIn[3]);
fclose(filesIn[4]);
fclose(filesIn[5]);
fclose(filesIn[6]);
fclose(filesIn[7]);
fclose(filesIn[8]);
fclose(filesIn[9]);
fclose(fileOut);
}
void getFile(){
int Seek = 0;
int currentSeek = 0;
int currentNum = 0;
int localLargestPrime = 0;
char *buffer = malloc(50);
fileOut = fopen("TextFiles/dataBin.txt", "rb");
rewind(fileOut);
while(!feof(fileOut)){
fseek(fileOut,Seek*sizeof(char)*20, SEEK_SET);
fgets(buffer,10,fileOut);
Seek++;
currentNum = atoi(buffer);
if(currentNum>localLargestPrime)
if(ChkPrim(currentNum) == 1){
localLargestPrime = currentNum;
currentSeek = Seek*sizeof(char)*20;
printf("the current seek is: %d\n", currentSeek);
}
}
printf("This is the largest Prime: %d\n", localLargestPrime);
}
int getLineNum(){
Seek = 0;
int index;
char c;
filesIn[0] = fopen("TextFiles/primes1.txt", "r");//read Text
filesIn[1] = fopen("TextFiles/primes2.txt", "r");//read Text
filesIn[2] = fopen("TextFiles/primes3.txt", "r");//read Text
filesIn[3] = fopen("TextFiles/primes4.txt", "r");//read Text
filesIn[4] = fopen("TextFiles/primes5.txt", "r");//read Text
filesIn[5] = fopen("TextFiles/primes6.txt", "r");//read Text
filesIn[6] = fopen("TextFiles/primes7.txt", "r");//read Text
filesIn[7] = fopen("TextFiles/primes8.txt", "r");//read Text
filesIn[8] = fopen("TextFiles/primes9.txt", "r");//read Text
filesIn[9] = fopen("TextFiles/primes10.txt", "r");//read Text
for(index = 0; index < 10; index++)
while((c = fgetc(filesIn[index])) != EOF)
if(c == '\n')
Seek++;
return Seek;
}