in reverie-ptrace/src/timer.rs [467:474]
fn is_timer_generated_signal(signal: &libc::siginfo_t) -> bool {
// The signal that gets sent is SIGPOLL. We reconfigured the signal
// number, but the struct info is the same. Per the perf manpage, signal
// notifications will come indicating either POLL_IN or POLL_HUP.
signal.si_signo == MARKER_SIGNAL as i32
&& (signal.si_code == i32::from(libc::POLLIN)
|| signal.si_code == i32::from(libc::POLLHUP))
}