As reported in id:"87sj80yb3e.fsf@kepler.schwinge.homeip.net",
after a GCC build (native, so three stages bootstrap), we got:
PID UID PPID PGrp Sess TH Vmem RSS %CPU User System Args 449 1000 3 1 1 10118 782M 198M 0.0 0:40.78 2:26.65 /hurd/fifo
The other processes, in particular two instances of ext2fs and one of ?exec, looked reasonable.