X-Git-Url: http://rtime.felk.cvut.cz/gitweb/can-benchmark.git/blobdiff_plain/94ca3189a01587b8ec96473cf4d284889ae618a9..5213ffa9e2ff09d8ff609b61a7cf589d03050477:/rtems/gw/libs/load.c

diff --git a/rtems/gw/libs/load.c b/rtems/gw/libs/load.c
new file mode 100644
index 0000000..ba7fac4
--- /dev/null
+++ b/rtems/gw/libs/load.c
@@ -0,0 +1,116 @@
+/*
+* Implements simple producer/consumer thread pair to cause load on the CPU.
+* 
+* Used in benchmarking the CAN gateway.
+*
+* Co-opted from http://support.dce.felk.cvut.cz/pos/cv3/src/semaphore.html. 
+*/
+
+#include <stdio.h>
+
+#include <pthread.h>
+#include <semaphore.h>
+
+#include "load.h"
+
+
+static void* produce(void* arg);
+static void* consume(void* arg);
+
+/* semaphores for consumer/producer pair */
+static sem_t produced, consumed;
+/* pthread handles for the loader */
+static pthread_t consumer, producer;
+static int n = 0;
+static char running = 0;
+
+static void* produce(void* arg){
+    while (1) {
+            sem_wait(&consumed);
+            n++;  /* increment n by 1 */
+            sem_post(&produced);
+            pthread_testcancel();
+    }
+    return NULL;
+}       
+
+static void* consume(void* arg){
+    while (1) {
+            sem_wait(&produced);
+            n--; /* aaand decrement */
+            sem_post(&consumed);
+            pthread_testcancel();
+    }
+    return NULL;
+}
+
+int start_thread_load(){
+    if (running == 0){
+        printf("Attempting to start load.\n");
+        int res;
+        running = 1;
+        res = sem_init(&consumed, 0, 0);
+        if (res < 0){
+            printf("Couldn't initialize consumed semaphore.\n");
+            return 1;
+        }
+        res = sem_init(&produced, 0, 1);
+        if (res < 0){
+            printf("Couldn't initialize produced semaphore.\n");
+            return 1;
+        }
+        
+        res = pthread_create(&producer, NULL, produce, NULL);
+        if (res < 0){
+            printf("Couldn't create producer thread.\n");
+            return 1;
+        }
+        
+        res = pthread_create(&consumer, NULL, consume, NULL);
+        if (res < 0){
+            printf("Couldn't create consumer thread.\n");
+            return 1;
+        }
+    
+        pthread_detach(producer);
+        pthread_detach(consumer);
+        printf("Load started succesfully.\n");
+        return 0;
+    } else {
+        printf("Load is already running.\n");
+        return 0;
+    }
+}
+
+/*
+* This function stops threads loading the CPU and destroys associated semaphores. 
+* 
+* No error handling currently, only tries to report errors.
+* 
+*/
+int end_thread_load(){
+    if (running == 1){
+        int res;
+        printf("Attempting to cancel producer thread.\n");
+        res = pthread_cancel(producer);
+        if (res != 0){
+            printf("Failed.\n");
+            /* Not sure what to do with error here, will have to figure out later. */
+        }
+        printf("Attempting to cancel consumer thread.\n");
+        res = pthread_cancel(consumer);
+        if (res != 0){
+            printf("Failed.\n");
+        }
+        printf("Preparing to destroy semaphores.\n");
+        sleep(1);
+        sem_destroy(&produced);
+        sem_destroy(&consumed);
+        running = 0;
+        printf("Finished.\n");
+        return 0;
+    } else {
+        printf("Load is not running.\n");
+        return 0;
+    }
+}
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