static L<Web> websMadeByProgram_parallel(S progID) {
  // TODO: clean up file handle in case of error
  IterableIterator<S> l = scanLog_iterator(progID, "webs-made.txt");
  fS src = progID;
  final L<Pair<Web, Int>> webs;
  
  int poolSize = numberOfCores(), queueSize = 20;
  NotifyingBlockingThreadPoolExecutor e = new(poolSize, queueSize, 15, TimeUnit.SECONDS);
  
  try {
    int i = 0;
    for (fS s : l) {
      ++i;
      final int _i = i;
      e.execute(r { pcall {
        SoftwareMadeWeb o = cast unstructure(s);
        Web web = o.web;
        if (web == null)
          web = (Web) unstructure(o.structure);
        if (web != null) synchronized(webs) {
          webs.add(pair(web_intern(web_setSourceIfEmpty(web, src)), _i));
        }
      }});
    }
    e.await();
  } finally {
    e.shutdown();
  }
  
  sortBySecondOfPairs_inPlace(webs);
  ret firstOfPairs(webs);
}