task2cpu.h File Reference

Go to the source code of this file.

Functions
int	mbdyn_task2cpu (int cpu)

Function Documentation

int mbdyn_task2cpu

(

int

cpu

)

Definition at line 56 of file task2cpu.cc.

References DEBUGCERR, and mbdyn_task2cpu_disabled.

{
        int             fd = -1;

#ifdef HAVE_THREADS
        pthread_mutex_lock(&::mbdyn_task2cpu_mutex);
#endif /* HAVE_THREADS */
        if (!::mbdyn_task2cpu_disabled) {
#ifdef HAVE_TASK2CPU
                fd = open("/dev/TASK2CPU", O_RDWR);
                if (fd != -1) {
                        ioctl(fd, 0, cpu);
                        close(fd);

                } else {
                        int save_errno = errno;
                        char *err_msg = strerror(save_errno);

                        silent_cerr("Error opening /dev/TASK2CPU ("
                                        << save_errno << ": " << err_msg << ";"
                                       " ignored)" << std::endl);
                        ::mbdyn_task2cpu_disabled = true;
                }
#elif defined(USE_PTHREAD_SETAFFINITY_NP)
                cpu_set_t cpuset;
                CPU_ZERO(&cpuset);
                CPU_SET(cpu, &cpuset);

                const pthread_t thread = pthread_self();

                int s = pthread_setaffinity_np(thread, sizeof(cpuset), &cpuset);

                if (0 != s) {
                        silent_cerr("warning: pthread_setaffinity_np failed with status " << s << std::endl);
                        goto failed;
                }

#ifdef DEBUG
                s = pthread_getaffinity_np(thread, sizeof(cpuset), &cpuset);

                if (0 != s) {
                        DEBUGCERR("warning: pthread_getaffinity_np failed with status " << s << std::endl);
                        goto failed;
                }

                for (int i = 0; i < CPU_SETSIZE; ++i) {
                        if (CPU_ISSET(i, &cpuset)) {
                                DEBUGCERR("thread " << cpu + 1 << " running at CPU " << i << std::endl);
                        }
                }
#endif
                fd = 1; // return 0

        failed:
                if (fd == -1) {
                        ::mbdyn_task2cpu_disabled = true;
                }
#else  /* ! HAVE_TASK2CPU */
                silent_cerr("/dev/TASK2CPU or pthread_getaffinity_np are not available" << std::endl);
                ::mbdyn_task2cpu_disabled = true;
#endif /* ! HAVE_TASK2CPU */
        }
#ifdef HAVE_THREADS
        pthread_mutex_unlock(&::mbdyn_task2cpu_mutex);
#endif /* HAVE_THREADS */

        return (fd == -1);
}