def _read(self):
        filepos = self._fp.tell()
        if filepos < 1:
            return ""
        destpos = max(filepos - self._chunk_size, 0)
        self._fp.seek(destpos)
        buf = self._fp.read(filepos - destpos)
        self._fp.seek(destpos)
        return buf
Start the scenario within threads.
dataset/ETHPy150Open Jahaja/psdash/psdash/log.py/ReverseFileSearcher._read--crossover with--dataset/ETHPy150Open openstack/rally/rally/plugins/common/runners/constant.py/_worker_process