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#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
/* Include gettid() */
#include <sys/types.h>
/* Include threading support. */
#include <pthread.h>
/* Include the LITMUS^RT API.*/
#include "litmus.h"
/* Catch errors.
*/
#define CALL( exp ) do { \
int ret; \
ret = exp; \
if (ret != 0) \
fprintf(stderr, "%s failed: %m\n", #exp);\
else \
fprintf(stderr, "%s ok.\n", #exp); \
} while (0)
#define TH_CALL( exp ) do { \
int ret; \
ret = exp; \
if (ret != 0) \
fprintf(stderr, "[%d] %s failed: %m\n", ctx->id, #exp); \
else \
fprintf(stderr, "[%d] %s ok.\n", ctx->id, #exp); \
} while (0)
#define TH_SAFE_CALL( exp ) do { \
int ret; \
fprintf(stderr, "[%d] calling %s...\n", ctx->id, #exp); \
ret = exp; \
if (ret != 0) \
fprintf(stderr, "\t...[%d] %s failed: %m\n", ctx->id, #exp); \
else \
fprintf(stderr, "\t...[%d] %s ok.\n", ctx->id, #exp); \
} while (0)
/* these are only default values */
int NUM_THREADS=3;
int NUM_SEMS=10;
#define MAX_SEMS 1000
#define EXEC_COST 10
#define PERIOD 100
/* The information passed to each thread. Could be anything. */
struct thread_context {
int id;
int fd;
int od[MAX_SEMS];
int count;
unsigned int rand;
};
void* rt_thread(void* _ctx);
int nested_job(struct thread_context* ctx, int *count, int *next);
int job(struct thread_context*);
#define OPTSTR "t:s:"
int main(int argc, char** argv)
{
int i;
struct thread_context* ctx;
pthread_t* task;
int fd;
int opt;
while((opt = getopt(argc, argv, OPTSTR)) != -1) {
switch(opt) {
case 't':
NUM_THREADS = atoi(optarg);
break;
case 's':
NUM_SEMS = atoi(optarg);
assert(NUM_SEMS <= MAX_SEMS);
break;
default:
fprintf(stderr, "Unknown option: %c\n", opt);
exit(-1);
break;
}
}
ctx = (struct thread_context*) calloc(NUM_THREADS, sizeof(struct thread_context));
task = (pthread_t*) calloc(NUM_THREADS, sizeof(pthread_t));
srand(0); /* something repeatable for now */
fd = open("semaphores", O_RDONLY | O_CREAT, S_IRUSR | S_IWUSR);
CALL( init_litmus() );
for (i = 0; i < NUM_THREADS; i++) {
ctx[i].id = i;
ctx[i].fd = fd;
ctx[i].rand = rand();
CALL( pthread_create(task + i, NULL, rt_thread, ctx + i) );
}
for (i = 0; i < NUM_THREADS; i++)
pthread_join(task[i], NULL);
return 0;
}
void* rt_thread(void* _ctx)
{
int i;
int do_exit = 0;
struct thread_context *ctx = (struct thread_context*)_ctx;
TH_CALL( init_rt_thread() );
/* Vary period a little bit. */
TH_CALL( sporadic_global(EXEC_COST, PERIOD + 10*ctx->id) );
for (i = 0; i < NUM_SEMS; i++) {
ctx->od[i] = open_fmlp_sem(ctx->fd, i);
if(ctx->od[i] < 0)
perror("open_fmlp_sem");
}
TH_CALL( task_mode(LITMUS_RT_TASK) );
printf("[%d] Waiting for TS release.\n ", ctx->id);
wait_for_ts_release();
ctx->count = 0;
do {
int which_sem = (int)(NUM_SEMS * (rand_r(&(ctx->rand)) / (RAND_MAX + 1.0)));
printf("[%d]: trying to get semaphore %d.\n", ctx->id, which_sem);
fflush(stdout);
TH_SAFE_CALL ( litmus_lock(which_sem) );
printf("[%d] got semaphore %d.\n", ctx->id, which_sem);
fflush(stdout);
do_exit = job(ctx);
printf("[%d]: freeing semaphore %d.\n", ctx->id, which_sem);
fflush(stdout);
TH_SAFE_CALL ( litmus_unlock(which_sem) );
if(!do_exit) {
sleep_next_period();
}
} while(!do_exit);
/*****
* 4) Transition to background mode.
*/
TH_CALL( task_mode(BACKGROUND_TASK) );
return NULL;
}
void dirty_kb(int kb)
{
int32_t one_kb[256];
int32_t sum = 0;
int32_t i;
for (i = 0; i < 256; i++)
sum += one_kb[i];
kb--;
/* prevent tail recursion */
if (kb)
dirty_kb(kb);
for (i = 0; i < 256; i++)
sum += one_kb[i];
}
int job(struct thread_context* ctx)
{
/* Do real-time calculation. */
dirty_kb(8);
/* Don't exit. */
//return ctx->count++ > 100;
//return ctx->count++ > 12000;
//return ctx->count++ > 120000;
return ctx->count++ > 30000; // controls number of jobs per task
}
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