5
He escrito el programa de prueba para probar SCHED_FIFO. Me enteré de que SCHED_FIFO no puede ser reemplazado por SCHED_OTHER hilos. Pero no pude explicar los resultados obtenidos cuando el mismo programa se ejecuta varias veces.El subproceso SCHED_FIFO se reemplaza por el subproceso SCHED_OTHER en Linux
/* Includes */
#include <unistd.h> /* Symbolic Constants */
#include <sys/types.h> /* Primitive System Data Types */
#include <errno.h> /* Errors */
#include <stdio.h> /* Input/Output */
#include <stdlib.h> /* General Utilities */
#include <pthread.h> /* POSIX Threads */
#include <string.h> /* String handling */
#include <sched.h>
/* prototype for thread routine */
void print_message_function (void *ptr);
void print_message_function1 (void *ptr);
/* struct to hold data to be passed to a thread
this shows how multiple data items can be passed to a thread */
typedef struct str_thdata
{
int thread_no;
int thread_value;
char message[100];
} thdata;
int main()
{
pthread_t thread1, thread2; /* thread variables */
thdata data1, data2; /* structs to be passed to threads */
/* initialize data to pass to thread 1 */
data1.thread_no = 1;
data1.thread_value = 0;
strcpy(data1.message, "Hello!");
/* initialize data to pass to thread 2 */
data2.thread_no = 2;
data2.thread_value = 10000;
strcpy(data2.message, "Hi!");
/* create threads 1 and 2 */
pthread_create (&thread1, NULL, (void *) &print_message_function, (void *) &data1);
pthread_create (&thread2, NULL, (void *) &print_message_function1, (void *) &data2);
/* Main block now waits for both threads to terminate, before it exits
If main block exits, both threads exit, even if the threads have not
finished their work */
pthread_join(thread1, NULL);
pthread_join(thread2, NULL);
/* exit */
exit(0);
} /* main() */
/**
* print_message_function is used as the start routine for the threads used
* it accepts a void pointer
**/
void print_message_function (void *ptr)
{
thdata *data;
data = (thdata *) ptr; /* type cast to a pointer to thdata */
struct sched_param param;
//int priority=10;
/* sched_priority will be the priority of the thread */
//param.sched_priority = priority;
/* only supported policy, others will result in ENOTSUP */
int policy = SCHED_OTHER;
/* scheduling parameters of target thread */
pthread_setschedparam(pthread_self(), policy, ¶m);
printf("Thread %d says sched policy %d \n", data->thread_no, SCHED_OTHER);
pthread_getschedparam(pthread_self(),&policy,¶m);
printf("Thread %d says %s %d \n", data->thread_no, data->message,policy);
int i=0;
/* do the work */
printf("Thread %d says %s %d \n", data->thread_no, data->message,(int)pthread_self());
for(i=0;i<100;i++)
printf("Thread %d says %d \n", data->thread_no,data->thread_value++);
pthread_exit(0); /* exit */
} /* print_message_function (void *ptr) */
void print_message_function1 (void *ptr)
{
thdata *data;
data = (thdata *) ptr; /* type cast to a pointer to thdata */
struct sched_param param;
int priority=10;
/* sched_priority will be the priority of the thread */
param.sched_priority = priority;
/* only supported policy, others will result in ENOTSUP */
int policy = SCHED_FIFO;
/* scheduling parameters of target thread */
pthread_setschedparam(pthread_self(), policy, ¶m);
printf("Thread %d says sched policy %d \n", data->thread_no, SCHED_FIFO);
pthread_getschedparam(pthread_self(),&policy,¶m);
printf("Thread %d says %s %d \n", data->thread_no, data->message,policy);
int i=0;
/* do the work */
printf("Thread %d says %s %d \n", data->thread_no, data->message,(int)pthread_self());
for(i=0;i<100;i++)
printf("Thread %d says %d \n", data->thread_no,data->thread_value++);
pthread_exit(0); /* exit */
} /* print_message_function (void *ptr) */
He conseguido resultados inesperados en múltiples ejecuciones donde he visto SCHED_FIFO sea invalidada por SCHED_OTHER hilo, es decir, como por programa, hilo 2 es en FIFO modo, mientras que el hilo 1 es SCHED_OTHER modo. He visto varias veces donde thread1 es reemplazado por thread1.
¿Alguien me puede ayudar a encontrar el problema?
Salida de 'sysctl -a | grep _rt'? – ninjalj
@martinjames kernel.sched_rt_period_us = 1000000 kernel.sched_rt_runtime_us = 950000 – GoT
estoy usando Ubuntu 11.10 con g ++ 4.6.1 – GoT