code in class 9-11

Code/class-10/futex/futex.c

@@ -0,0 +1,27 @@
+/* 
+ * futex.c
+ * by WN @ Oct. 22, 2010
+ */
+
+#include <linux/kernel.h>
+#include <linux/futex.h>
+
+#include <xasm/asm_syscall.h>
+#include <xasm/futex.h>
+
+int
+futex_wait(void * addr, int val)
+{
+	return INTERNAL_SYSCALL_int80(futex, 6,
+			(uintptr_t)addr, FUTEX_WAIT_PRIVATE, val, NULL, NULL, NULL);
+}
+
+int
+futex_wake(void * addr, int nr)
+{
+	return INTERNAL_SYSCALL_int80(futex, 6,
+			(uintptr_t)addr, FUTEX_WAKE_PRIVATE, nr, NULL, NULL, 0);
+}
+
+// vim:ts=4:sw=4
+

Code/class-10/futex/futex.h

@@ -0,0 +1,22 @@
+/* 
+ * xasm/futex.h
+ * by WN @ Oct. 20, 2010
+ */
+
+/* wrapper of correponding futex system calls */
+
+#ifndef __X86_FUTEX_H
+#define __X86_FUTEX_H
+
+#include <defs.h>
+
+extern int
+futex_wait(void * addr, int val);
+
+extern int
+futex_wake(void * addr, int nr);
+
+#endif
+
+// vim:ts=4:sw=4
+

Code/class-11/PC.c

@@ -0,0 +1,94 @@
+/*
+ * =============================================================================
+ *
+ *       Filename:  PC.c
+ *
+ *    Description:  producer && consumer.
+ *
+ *        Version:  0.0.1
+ *        Created:  12/06/2011 10:28:09 AM
+ *       Revision:  r1
+ *       Compiler:  gcc (Ubuntu/Linaro 4.4.4-14ubuntu5) 4.4.5
+ *
+ *         Author:  Fu Haiping (forhappy), [email protected]
+ *        Company:  ICT ( Institute Of Computing Technology, CAS )
+ *
+ * =============================================================================
+ */
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include </usr/include/semaphore.h>
+
+#define BUFF_SIZE   5		/* total number of slots */
+#define NP          3		/* total number of producers */
+#define NC          3		/* total number of consumers */
+#define NITERS      4		/* number of items produced/consumed */
+
+typedef struct {
+    int buf[BUFF_SIZE];   /* shared var */
+    int in;         	  /* buf[in%BUFF_SIZE] is the first empty slot */
+    int out;        	  /* buf[out%BUFF_SIZE] is the first full slot */
+    sem_t full;     	  /* keep track of the number of full spots */
+    sem_t empty;    	  /* keep track of the number of empty spots */
+    sem_t mutex;    	  /* enforce mutual exclusion to shared data */
+} sbuf_t;
+
+sbuf_t shared;
+
+void *Producer(void *arg)
+{
+    int i, item, index;
+
+    index = (int)arg;
+
+    for (i=0; i < NITERS; i++) {
+
+        /* Produce item */
+        item = i;	
+
+        /* Prepare to write item to buf */
+
+        /* If there are no empty slots, wait */
+        sem_wait(&shared.empty);
+        /* If another thread uses the buffer, wait */
+        sem_wait(&shared.mutex);
+        shared.buf[shared.in] = item;
+        shared.in = (shared.in+1)%BUFF_SIZE;
+        printf("[P%d] Producing %d ...\n", index, item); fflush(stdout);
+        /* Release the buffer */
+        sem_post(&shared.mutex);
+        /* Increment the number of full slots */
+        sem_post(&shared.full);
+
+        /* Interleave  producer and consumer execution */
+        if (i % 2 == 1) sleep(1);
+    }
+    return NULL;
+}
+
+void *Consumer(void *arg)
+{
+    /* Fill in the code here */
+}
+
+int main()
+{
+    pthread_t idP, idC;
+    int index;
+
+    sem_init(&shared.full, 0, 0);
+    sem_init(&shared.empty, 0, BUFF_SIZE);
+
+    /* Insert code here to initialize mutex*/
+
+    for (index = 0; index < NP; index++)
+    {  
+       /* Create a new producer */
+       pthread_create(&idP, NULL, Producer, (void*)index);
+    }
+
+    /* Insert code here to create NC consumers */
+
+    pthread_exit(NULL);
+}

Code/class-11/sem-example-good.c

@@ -0,0 +1,90 @@
+/*
+ * =============================================================================
+ *
+ *       Filename:  sem-example-good.c
+ *
+ *    Description:  sem good example
+ *
+ *        Version:  0.0.1
+ *        Created:  12/06/2011 10:32:51 AM
+ *       Revision:  r1
+ *       Compiler:  gcc (Ubuntu/Linaro 4.4.4-14ubuntu5) 4.4.5
+ *
+ *         Author:  Fu Haiping (forhappy), [email protected]
+ *        Company:  ICT ( Institute Of Computing Technology, CAS )
+ *
+ * =============================================================================
+ */
+#include <semaphore.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+int main(int argc, char **argv)
+{
+  int fd, i,count=0,nloop=10,zero=0,*ptr;
+  sem_t *mutex;
+  int shm;
+
+  //open a file and map it into memory
+if ((shm = shm_open("myshm", O_RDWR | O_CREAT, S_IRWXU)) < 0) {
+    perror("shm_open");
+    exit(1);
+  }
+
+  if ( ftruncate(shm, sizeof(sem_t)) < 0 ) {
+    perror("ftruncate");
+    exit(1);
+  }
+
+  if ((mutex = mmap(NULL, sizeof(sem_t), PROT_READ | PROT_WRITE,
+      MAP_SHARED, shm, 0)) == MAP_FAILED) {
+    perror("mmap");
+    exit(1);
+  }
+
+  if (sem_init(mutex, 1, 1) < 0) {
+    perror("semaphore initialization");
+    exit(1);
+  }  
+#if 0
+  fd = open("log.txt",O_RDWR|O_CREAT,S_IRWXU);
+  write(fd,&zero,sizeof(int));
+  ptr = mmap(NULL,sizeof(int),PROT_READ |PROT_WRITE,MAP_SHARED,fd,0);
+  close(fd);
+
+  /* create, initialize semaphore */
+  if( sem_init(&mutex,1,1) < 0)
+    {
+      perror("semaphore initilization");
+      exit(0);
+    }
+#endif
+  if (fork() == 0) { /* child process*/
+    for (i = 0; i < nloop; i++) {
+      sem_wait(mutex);
+      printf("child entered crititical section: %d\n", (*ptr)++);
+      sleep(2);
+      printf("child leaving critical section\n");
+      sem_post(mutex);
+      sleep(1);
+    }
+    exit(0);
+  }
+  /* back to parent process */
+  for (i = 0; i < nloop; i++) {
+    sem_wait(mutex);
+    printf("parent entered critical section: %d\n", (*ptr)++);
+    sleep(2);
+    printf("parent leaving critical section\n");
+    sem_post(mutex);
+    sleep(1);
+  }
+  exit(0);
+}

Code/class-11/sem-example.c

@@ -0,0 +1,68 @@
+/*
+ * =============================================================================
+ *
+ *       Filename:  sem-example.c
+ *
+ *    Description:  sem example
+ *
+ *        Version:  0.0.1
+ *        Created:  12/06/2011 10:30:44 AM
+ *       Revision:  r1
+ *       Compiler:  gcc (Ubuntu/Linaro 4.4.4-14ubuntu5) 4.4.5
+ *
+ *         Author:  Fu Haiping (forhappy), [email protected]
+ *        Company:  ICT ( Institute Of Computing Technology, CAS )
+ *
+ * =============================================================================
+ */
+#include <semaphore.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+int main(int argc, char **argv)
+{
+  int fd, i,count=0,nloop=10,zero=0,*ptr;
+  sem_t mutex;
+
+  //open a file and map it into memory
+
+  fd = open("log.txt",O_RDWR|O_CREAT,S_IRWXU);
+  write(fd,&zero,sizeof(int));
+  ptr = mmap(NULL,sizeof(int),PROT_READ |PROT_WRITE,MAP_SHARED,fd,0);
+  close(fd);
+
+  /* create, initialize semaphore */
+  if( sem_init(&mutex,1,1) < 0)
+    {
+      perror("semaphore initilization");
+      exit(0);
+    }
+  if (fork() == 0) { /* child process*/
+    for (i = 0; i < nloop; i++) {
+      sem_wait(&mutex);
+      printf("child entered crititical section: %d\n", (*ptr)++);
+      sleep(2);
+      printf("child leaving critical section\n");
+      sem_post(&mutex);
+      sleep(1);
+    }
+    exit(0);
+  }
+  /* back to parent process */
+  for (i = 0; i < nloop; i++) {
+    sem_wait(&mutex);
+    printf("parent entered critical section: %d\n", (*ptr)++);
+    sleep(2);
+    printf("parent leaving critical section\n");
+    sem_post(&mutex);
+    sleep(1);
+  }
+  exit(0);
+}