From 7a73162607544204032aa66cce755daf21edebda Mon Sep 17 00:00:00 2001
From: Matt Strapp <matt@mattstrapp.net>
Date: Tue, 24 May 2022 11:18:46 -0500
Subject: Graduate

Signed-off-by: Matt Strapp <matt@mattstrapp.net>
---
 csci4061/112320_breakout/sol-condition_variables.c | 128 +++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 csci4061/112320_breakout/sol-condition_variables.c

(limited to 'csci4061/112320_breakout/sol-condition_variables.c')

diff --git a/csci4061/112320_breakout/sol-condition_variables.c b/csci4061/112320_breakout/sol-condition_variables.c
new file mode 100644
index 0000000..86cafb1
--- /dev/null
+++ b/csci4061/112320_breakout/sol-condition_variables.c
@@ -0,0 +1,128 @@
+#define NUM_ARGS 0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <string.h>
+#include <time.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <sys/time.h>
+
+long condTotal = 0;
+
+struct queue {
+
+	int vals[100];
+	int index; //indicates the next available spot
+};
+
+struct condQueue {
+
+	struct queue* q;
+	pthread_cond_t* cond;
+	pthread_mutex_t* mutex;
+};
+
+
+
+void insert(struct queue* q, int val) {
+
+	q->vals[q->index] = val;
+	++q->index;
+}
+
+int delete(struct queue* q) {
+
+	--q->index;
+	int val = q->vals[q->index];
+	return val;
+}
+
+// TODO: Insert code to use a condition variable.
+void *condProducer(void* arg) {
+
+	// Random delay. DO NOT REMOVE!
+	usleep(rand() % 1000);
+
+	struct condQueue* cq = (struct condQueue*) arg;
+
+	pthread_mutex_lock(cq->mutex);
+
+	// Counter.
+	static int in = 0;
+	++in;
+
+	// Add an element to the queue.
+	insert(cq->q, in);
+
+	pthread_cond_signal(cq->cond); //to send signal to any waiting consumer
+	pthread_mutex_unlock(cq->mutex);
+}
+
+// TODO: Insert code to use a condition variable.
+void *condConsumer(void* arg) {
+
+	// Random delay. DO NOT REMOVE!
+	usleep(rand() % 1000);
+
+	struct condQueue* cq = (struct condQueue*) arg;
+
+	pthread_mutex_lock(cq->mutex);
+	while (cq->q->index < 1) pthread_cond_wait(cq->cond, cq->mutex);//wait if buffer is empty
+
+	// Remove an element from the queue.
+	condTotal += delete(cq->q);
+
+	pthread_mutex_unlock(cq->mutex);
+}
+
+int main(int argc, char** argv) {
+
+	if (argc != NUM_ARGS + 1) {
+
+		printf("Wrong number of args, expected %d, given %d\n", NUM_ARGS, argc - 1);
+		exit(1);
+	}
+
+	// Seed the random generator.
+	srand(time(NULL));
+
+	// Create threads.
+	pthread_t condPool[100];
+
+	struct timeval start;
+	gettimeofday(&start, NULL);
+
+	// Create the cond variable controlled task queue.
+	struct condQueue* cq = (struct condQueue*) malloc(sizeof(struct condQueue));
+	cq->q = (struct queue*) malloc(sizeof(struct queue));
+	cq->q->index=0;
+
+	// Allocate memory and initialize condition variable and mutex
+	cq->cond = (pthread_cond_t*) malloc(sizeof(pthread_cond_t));
+	cq->mutex = (pthread_mutex_t*) malloc(sizeof(pthread_mutex_t));
+	pthread_cond_init(cq->cond, NULL);
+	pthread_mutex_init(cq->mutex, NULL);
+
+	// Launch them.
+	for (int i=0; i < 50; ++i) {
+
+		pthread_create(&condPool[i], NULL, condProducer, (void*) cq); //start 50 producer threads
+		pthread_create(&condPool[50 + i], NULL, condConsumer, (void*) cq); //start 50 consumer threads
+	}
+
+	for (int i=0; i < 100; ++i) pthread_join(condPool[i], NULL); //wait for all the threads to be finished
+
+	struct timeval end;
+	gettimeofday(&end, NULL);
+
+	printf("Cond Test: \nTotal of buffer = %ld\n", condTotal);
+	printf("Time (in us) to run = %ld\n\n", ((end.tv_sec - start.tv_sec) * 1000000) + (end.tv_usec - start.tv_usec));
+
+	}
-- 
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