pg_autovacuum questions

Hi all,
only two questions:
  1) where is the documentation about the
     meanings of option passed to pg_autovacuum

  2) Is it normal that a strace wake up it during a sleep?

     From linux doc:
          sleep()  makes  the  current  process  sleep until seconds
          seconds have elapsed or a signal arrives which is not ignored.


     for fix this is better substitute each sleep with:

          int a = <second_to_sleep>
          while (a>0) a=sleep(a);

     ( I didn't find the signal to ignore :-) )


Regards
Gaetano Mendola