static gint
poll_event_wait (void (*callback) (gint fd, gint events, gpointer user_data), gpointer user_data)
{
gint i, ready;
for (i = 0; i < poll_fds_size; ++i)
poll_fds [i].revents = 0;
mono_thread_info_set_flags (MONO_THREAD_INFO_FLAGS_NO_GC);
MONO_ENTER_GC_SAFE;
ready = mono_poll (poll_fds, poll_fds_size, -1);
MONO_EXIT_GC_SAFE;
mono_thread_info_set_flags (MONO_THREAD_INFO_FLAGS_NONE);
if (ready == -1) {
/*
* Apart from EINTR, we only check EBADF, for the rest:
* EINVAL: mono_poll() 'protects' us from descriptor
* numbers above the limit if using select() by marking
* then as POLLERR. If a system poll() is being
* used, the number of descriptor we're passing will not
* be over sysconf(_SC_OPEN_MAX), as the error would have
* happened when opening.
*
* EFAULT: we own the memory pointed by pfds.
* ENOMEM: we're doomed anyway
*
*/
switch (errno)
{
case EINTR:
{
ready = 0;
break;
}
case EBADF:
{
ready = poll_mark_bad_fds (poll_fds, poll_fds_size);
break;
}
default:
g_error ("poll_event_wait: mono_poll () failed, error (%d) %s", errno, g_strerror (errno));
break;
}
}
if (ready == -1)
return -1;
if (ready == 0)
return 0;
g_assert (ready > 0);
for (i = 0; i < poll_fds_size; ++i) {
gint fd, events = 0;
if (poll_fds [i].fd == -1)
continue;
if (poll_fds [i].revents == 0)
continue;
fd = poll_fds [i].fd;
if (poll_fds [i].revents & (MONO_POLLIN | MONO_POLLERR | MONO_POLLHUP | MONO_POLLNVAL))
events |= EVENT_IN;
if (poll_fds [i].revents & (MONO_POLLOUT | MONO_POLLERR | MONO_POLLHUP | MONO_POLLNVAL))
events |= EVENT_OUT;
if (poll_fds [i].revents & (MONO_POLLERR | MONO_POLLHUP | MONO_POLLNVAL))
events |= EVENT_ERR;
callback (fd, events, user_data);
if (--ready == 0)
break;
}
return 0;
}
static gsize
sampling_thread_func (gpointer unused)
{
MonoInternalThread *thread = mono_thread_internal_current ();
thread->flags |= MONO_THREAD_FLAG_DONT_MANAGE;
ERROR_DECL (error);
MonoString *name = mono_string_new_checked (mono_get_root_domain (), "Profiler Sampler", error);
mono_error_assert_ok (error);
mono_thread_set_name_internal (thread, name, FALSE, FALSE, error);
mono_error_assert_ok (error);
mono_thread_info_set_flags (MONO_THREAD_INFO_FLAGS_NO_GC | MONO_THREAD_INFO_FLAGS_NO_SAMPLE);
int old_policy;
struct sched_param old_sched;
pthread_getschedparam (pthread_self (), &old_policy, &old_sched);
/*
* Attempt to switch the thread to real time scheduling. This will not
* necessarily work on all OSs; for example, most Linux systems will give
* us EPERM here unless configured to allow this.
*
* TODO: This does not work on Mac (and maybe some other OSs). On Mac, we
* have to use the Mach thread policy routines to switch to real-time
* scheduling. This is quite tricky as we need to specify how often we'll
* be doing work (easy), the normal processing time needed (also easy),
* and the maximum amount of processing time needed (hard). This is
* further complicated by the fact that if we misbehave and take too long
* to do our work, the kernel may knock us back down to the normal thread
* scheduling policy without telling us.
*/
struct sched_param sched = { .sched_priority = sched_get_priority_max (SCHED_FIFO) };
pthread_setschedparam (pthread_self (), SCHED_FIFO, &sched);
MonoProfilerSampleMode mode;
init:
mono_profiler_get_sample_mode (NULL, &mode, NULL);
if (mode == MONO_PROFILER_SAMPLE_MODE_NONE) {
mono_profiler_sampling_thread_wait ();
if (!mono_atomic_load_i32 (&sampling_thread_running))
goto done;
goto init;
}
clock_init (mode);
for (guint64 sleep = clock_get_time_ns (); mono_atomic_load_i32 (&sampling_thread_running); clock_sleep_ns_abs (sleep)) {
uint32_t freq;
MonoProfilerSampleMode new_mode;
mono_profiler_get_sample_mode (NULL, &new_mode, &freq);
if (new_mode != mode) {
clock_cleanup ();
goto init;
}
sleep += 1000000000 / freq;
FOREACH_THREAD_SAFE_EXCLUDE (info, MONO_THREAD_INFO_FLAGS_NO_SAMPLE) {
g_assert (mono_thread_info_get_tid (info) != sampling_thread);
/*
* Require an ack for the last sampling signal sent to the thread
* so that we don't overflow the signal queue, leading to all sorts
* of problems (e.g. GC STW failing).
*/
if (profiler_signal != SIGPROF && !mono_atomic_cas_i32 (&info->profiler_signal_ack, 0, 1))
continue;
mono_threads_pthread_kill (info, profiler_signal);
mono_atomic_inc_i32 (&profiler_signals_sent);
} FOREACH_THREAD_SAFE_END
}
