Just a note, I haven't investigated yet and don't have time to do so tonight:
I just updated my slightly older -current kernel to -current as of a few
minutes ago (eager to look at the performance with cache enabled), but
for some reason the new kernel does not boot:

                           Starting up the system...

               To perform system maintenance instead, press <Esc>

NetBSD/sgimips 2.99.10 Bootstrap, Revision 1.2
(martin@night-porter.duskware.de, Tue Nov 16 17:11:31 CET 2004)
                                                               
devopen: scsi(0)disk(1)rdisk(0)partition(0) type scsi file netbsd
2018176+158284 [74240+63953]=0x23556c                            
[ Kernel symbol table missing! ]     
                                
and there the machine hangs. More experiments will have to wait untill
tomorrow...

Martin