probe ruby.method.entry, ruby.cmethod.entry {
  if((classname =~ "Array") && (methodname =~ "push"))
      printf("%d -> %s::%s %s:%d\n", tid(), classname, methodname, file, line);
}

probe ruby.method.return, ruby.cmethod.return {
  if((classname =~ "Array") && (methodname =~ "push"))
    printf("%d <- %s::%s %s:%d\n", tid(), classname, methodname, file, line);
}