8000 添加生产者消费者原型，当然也不能保证满足各种测试条件，添加需要解决问题Readme.md · home-coder/ring-buffer@572b56a · GitHub
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添加生产者消费者原型，当然也不能保证满足各种测试条件，添加需要解决问题Readme.md
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‎README.md

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@@ -17,7 +17,11 @@ http://www.cnblogs.com/Anker/p/3481373.html
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2.内核数据写入，与mmap后的用户空间取走这个buffer的数据如何同步
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3.内核模块的地址如何在用户空间操作
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针对上面的问题，如下思考
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《针对上面的问题，如下思考》
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经过x86测试，得知写入数据大于ringbuffer给出的最大尺寸4096后，剩余的数据虽然走kfifo_put方法，但是数据并没有写入或者覆盖掉起始处的buffer，导致数据丢失，
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所有后续 需要针对这个问题进行判断：如果缓冲区满了就等待，当读者将数据取走腾出空间了，写者再写入。这样写线程可以让出cpu，让他在这个等待间隙做其它的事情。
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当然我的测试方法是写者很快，而读者很慢的情景
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测试：
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需要针对helper中的生产者消费者 模型熟练掌握以后，在将kfifo的项目代码改编成包含这种模式的，目的是解决上面的问题 《针对上面的问题，如下思考》。

‎helper/linux/Makefile

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@@ -1,16 +1,23 @@
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export ARCH=arm
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CC = ~/basic/cross_compile/gcc-4.6.2-glibc-2.13-linaro-multilib-2011.12/fsl-linaro-toolchain/bin/arm-fsl-linux-gnueabi-gcc
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#CC = gcc
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CFLAGS = -O2 -Wall --static
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ARCH = x86
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#ARCH = arm
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ifeq ($(ARCH), arm)
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export ARCH=arm
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CC = ~/basic/cross_compile/gcc-4.6.2-glibc-2.13-linaro-multilib-2011.12/fsl-linaro-toolchain/bin/arm-fsl-linux-gnueabi-gcc
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else
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CC = gcc
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endif
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CFLAGS = -O2 --static -DDBG_TEST
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INCLUDE = -I ./include
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all:mmap hello
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all:mmap hello product-consumer
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mmap:mmap.o
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${CC} ${CFLAGS} mmap.o -o $@
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rm -rf *.o
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hello:hello.o
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${CC} ${CFLAGS} hello.o -o $@
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product-consumer:product-consumer.o
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${CC} ${CFLAGS} product-consumer.o -o $@ -lpthread
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clean:
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rm -rf *.o mmap
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rm -rf *.o mmap hello product-consumer

‎helper/linux/hello

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‎helper/linux/hello.o

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‎helper/linux/product-consumer.c

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#include <stdio.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <pthread.h>
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#define MAXLENGTH 10 //the maxlength of queue
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typedef char * datatype;
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typedef struct node { //define node
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datatype name;
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struct node *next;
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} node;
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typedef struct queue { //define queue
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node *front, *rear;
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int len;
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} queue;
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void queue_init(queue *q)
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{
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q->front = q->rear = NULL;
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q->len = 0;
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}
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void queue_put(queue *q, datatype new_name)//入队
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{
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node *mynode = (node *)malloc(sizeof(node));
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mynode->name = new_name;
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mynode->next = NULL;
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if (q->rear)
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q->rear->next = mynode;
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q->rear = mynode;
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if (q->front == NULL)
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q->front = mynode;
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q->len++;
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}
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datatype queue_get(queue *q) //出队
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{
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node *mynode;
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datatype myname;
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if (q->front != NULL)
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mynode = q->front;
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myname = mynode->name;
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q->front = q->front->next;
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q->len--;
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free(mynode);
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return myname;
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}
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void queue_print(queue *q) //print queue
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{
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node *tmp = q->front;
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while(tmp != NULL)
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{
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printf("%s ", tmp->name);
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tmp = tmp->next;
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}
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printf("\n");
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}
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/*生产者与消费者函数*/
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/*define mutex and condtion var*/
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pthread_cond_t q_not_full = PTHREAD_COND_INITIALIZER;
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pthread_cond_t q_not_empty = PTHREAD_COND_INITIALIZER;
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pthread_mutex_t qlock = PTHREAD_MUTEX_INITIALIZER;
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/*
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* producer function
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*/
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void producer(void *q)
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{
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// printf("start porducer:\n");
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queue *qt = q; //传入的队列
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while(1)
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{
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pthread_mutex_lock(&qlock);
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// printf("producer has locked the qlock\n");
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while(qt->len >= MAXLENGTH) //queue is full
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{
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// printf("producer is going to waiting\n");
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pthread_cond_wait(&q_not_full, &qlock);
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}
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queue_put(qt, "* ");
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// printf("after producer: queue's length is %d\n", qt->len);
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pthread_mutex_unlock(&qlock);
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pthread_cond_signal(&q_not_empty);
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// printf("producer has unlocked the qlock\n");
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// sleep(1);
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}
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}
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/*
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* consumer function
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*/
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void consumer(void *q)
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{
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// printf("start consumer:\n");
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queue *qt = q;
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while(1)
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{
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pthread_mutex_lock(&qlock);
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// printf("consumer has locked the qlock\n");
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while(qt->len <= 0) //queue is empty
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{
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// printf("consumer is going to waiting\n");
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pthread_cond_wait(&q_not_empty, &qlock);
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}
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datatype back_name = queue_get(qt);
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// printf("after consumer, queue's length is %d\n", qt->len);
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pthread_mutex_unlock(&qlock);
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pthread_cond_signal(&q_not_full);
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// now process the back_name
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// printf("cousumer has unlocked the qlock\n");
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// sleep(1);
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}
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}
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//gcc编译时加上-lpthread
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int main() {
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pthread_t tid1, tid2;
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queue *q=(queue *)malloc(sizeof(queue));
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queue_init(q);
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#ifdef DBG_TEST
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queue_put(q, "one");
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queue_put(q, "two");
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queue_put(q, "three");
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queue_get(q);
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printf("len = %d\n", q->len);
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queue_print(q);
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#endif
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long stime = clock();
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long etime = clock();
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pthread_create(&tid1, NULL, (void *)producer, (void *)q);
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pthread_create(&tid2, NULL, (void *)consumer, (void *)q);
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while((float)(etime-stime)/CLOCKS_PER_SEC < 0.00001)
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{
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etime = clock();
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}
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return 0;
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}

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