#4349 NORM Never A: Improve startup speed

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#4349: Improve startup speed
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  Reporter:  wmb at firmworks.com  |       Owner:  cscott        
      Type:  defect             |      Status:  new           
  Priority:  normal             |   Milestone:  Never Assigned
 Component:  distro             |     Version:                
Resolution:                     |    Keywords:                
  Verified:  0                  |  
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Comment(by wmb at firmworks.com):

 I thought of another way to eliminate the udev time from startup -
 I just let the system come up, then made a tar file of the dev directory.
 I replaced "start_udev" in rc.sysinit with "(cd /; tar xf /etc/dev.tar)"

 With that change, I now get to the shell prompt in just under 30 seconds,
 a 6-second improvement from the last milestone and a 17 second improvement
 from the starting point.

 We can start udev later in the process to pick up USB devices.

 I just put some "echo x" lines in start_udev to see where it is taking so
 much time.  About half of the time is just stupid - it reads the file
 /etc/udev/makedev/50-udev.nodes, then runs /sbin/MAKEDEV on that list of
 files, preparing the argument list with a shell function replacement for
 xargs.  That step takes about 2 seconds to create a grand total of 28 /dev
 entries, 8 of which are for devices that we don't even have (parport0-3
 and lp0-3).

 In contrast, the "tar" technique takes 0.07 seconds to create the entire
 /dev/ hierarchy.

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Ticket URL: <https://dev.laptop.org/ticket/4349#comment:3>
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