Replacing rc(8) (Was: FreeBSD Boot Times)

Peter Jeremy peter at rulingia.com
Thu Jun 21 12:28:19 UTC 2012


On 2012-Jun-18 19:18:57 -0400, Brandon Falk <bfalk_bsd at brandonfa.lk> wrote:
>As the original poster of this thread, I can also say that Doug is 
>correct. The issue is not rc, it is the actual kernel boot process. 

I've videoed my netbook rebooting and gone through the video in slow
motion and that definitely doesn't match what I see.

>When it comes to a desktop/laptop/simple server and all you do with rc 
>is configure a static IP, start dbus/hal/sshd, and maybe launch a few 
>jails... at least 90-98% of the boot process is spent doing the kernel work.

In my case, starting from when the screen blanks after a reboot, the
breakdown is:
 7.4s - POST + BIOS splash (including ~1s waiting for input)
 4.4s - boot0/1/2, starting loader (including boot spinners)
 1.5s - loading kernel
11.0s - loader countdown
 7.0s - kernel startup
32.0s - rc scripts ("mounting root" through VTY login prompt)
 5.0s - X + xdm startup

Note that the majority of kernel probe time is:
 2000ms - atkbd
  750ms - ata
  500ms - memory probe
  500ms - ath0
  450ms - psm0

So, in my case, rc scripts account for just under 50% of the total
boot time and 50% of the remainder are various "waiting for input"
timeouts.  The kernel amounts for 10% of the total time and 50% of
that is 4 devices.  I intend to work through the rc process in more
detail to see where I can reduce the elapsed time.

-- 
Peter Jeremy
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