Re: asymmetric smp

[John Nemeth <jnemeth%cue.bc.ca@localhost>]

On Apr 2,  1:55pm, Johnny Billquist wrote:
} On 2014-04-01 23:04, Warner Losh wrote:
} > On Apr 1, 2014, at 5:49 AM, Johnny Billquist <bqt%softjar.se@localhost> 
wrote:
} >
} >> Good points.
} >> Is this the right time to ask why booting NetBSD on a VAX (a 3500) now 
takes more than 15 minutes? What is the system doing all that time???
} >
} > FreeBSD used to take forever to boot on certain low-end ARM CPUs with 
/etc/rc.d after it was imported from NetBSD. This was due to crappy root-device 
performance (100kB/s is enough for anybody, right?) and crappy, at the time, 
pmap code that caused excess page traffic in the /etc/rc.d environment. Perhaps 
those areas would be fruitful to profile? Also, there were some inefficiencies 
that were either the result of a botched port, or were basic to the system that 
got fixed. Between fixing all these things, the boot time went from 10 minutes 
down to ~20s.
} 
} Always nice with some ideas. The problem here is that this used to be 
} way faster in the past, but have slowed down recently.
} 
} The time between entering a username and getting the password prompt in 
} the same 3500 with the latest release is something like 30 seconds.
} 
} This is on an otherwise idle system, where boot has completed. 30 
} seconds (approximately, I should time it) just from pressing enter after 
} the username, until I just get the "Password:" prompt seems incredible 
} to me.
} 
} The root fs in on nfs, as I'm running the machine diskless. Disk is 
} served from a -current NetBSD/alpha system sitting right next to it. And 
} I have changed the Alpha to run at 10 MB/s half duplex, and I have 2k 
} block size for NFS. Login is obviously already running, since that is 
} what also prompts for the username, and doing it twice should even put 
} some stuff in local cache.

     Uh, actually getty does the initial prompt for username on
the console.  After collecting the username, getty execs login.

}-- End of excerpt from Johnny Billquist