Rumor has it that thorsten may have mentioned these words:
personally, i found it easier to just leave the machine turned on in a
quiet corner, rather than go through re-mounting/chroot each time i want
to work on it. i tend to find it serves as a little reminder/motivation
too, and it means you can set off the huge compiles and leave the machine
working whilst you get on with things like sleep ;)
If this is your first build of LFS I would encourage you to leave the
system running, there are too many things which can mess up rebooting the
system. Best thing for the first time is to follow the book as straight as
possible (assuming you are not very familiar with linux at this time and
know what you are doing).
If you have 1) time to tinker a bit before actually starting the LFS build,
and 2) another (preferably faster) machine available, there's a program
called distcc on the LFS Live CD that can distribute compilations across
multiple machines on the network.
I was hoping to have a hint and *maybe* patches to help people use this
type of setup by now, but familial duties has unfortunately compromised
much of my available free time in the last couple of weeks or so.
However, I can explain the basics in a nutshell:
1) boot your desktop machine and your laptop with a LFS LiveCD (make sure
you have the exact same version for both CDs. Altho distcc is normally not
very picky about stuff like that, making sure everything's on "the same
sheet of music" could nip a problem in the bud later on.)
2) Set up the networking on each machine and either a) assign each an IP
address, or if you're using DHCP, find out what IP addresses were assigned
to each machine. You're gonna need this later.
2.5) Let's assume for now that your on a trusted network (i.e. no external
internet access) and your IPs are 10.10.10/24. Your desktop machine is
10.10.10.2 and your laptop is 10.10.10.3.
3) Set up the environment necessary for distcc. On your desktop machine,
start the distcc daemon by typing:
distccd -a 10.10.10/24
The distcc daemon will complain that there's no 'distcc' user, but it
should work anyway.
=-=-=-=-= OK, what follows is what I haven't had a chance to tinker with...
you're gonna have to frobnicate with this stuff a bit, methinks... ;-)
=-=-=-=-=-=
4) I don't remember if you have to run a copy of the distccd daemon on the
client machine (in this case, the laptop) to use it for compilation as
well: If so, just start a daemon there using the same command listed above:
distccd -a 10.10.10/24
5) On your laptop, you're going to have to set up the environment to tell
distcc/gcc to be able to use the other machine(s); in this case, you'd need
to set an environment variable with the hostnames or ip addresses to all
the machines running the distccd daemon:
export DISTCC_HOSTS='10.10.10.2 10.10.10.3'
The hosts listed in the DISTCC_HOSTS environment variable should be ordered
with fastest machines first, and slowest machines last. So if your desktop
is much faster (most usually are) you'll want to make sure that IP address
is first.
Now, you're going to have to tell all the makefiles to use 'parallel
compiling' -- so go into the config/general.ent file, and where you see this:
<!ENTITY jlevel "">
you'll need to change that entry. There's the easy way, but *may* not work
right for all makefiles in the profile. If it doesn't work, don't worry -
it won't hurt anything, but you won't get distributed compiling, either.
Change the entry to this, and give this a try:
<!ENTITY jlevel "-j4 CC=distcc">
If the makefile honors the CC environment variable, all is good, and you
should be zooming. As far as I know, most if not all should honor this. If
that setting above works for all but one or two packages, then I'd say run
with it.
However, if you want to *force* distcc usage for all packages, you need to
trick the LFS LiveCD environment into thinking it's just running gcc, when
in fact it's running distcc. Run these commands:
mkdir /usr/local/distcc/bin
cd /usr/local/distcc/bin
ln -s /usr/bin/distcc gcc
ln -s /usr/bin/distcc cc
ln -s /usr/bin/distcc g++
ln -s /usr/bin/distcc c++
export PATH=/usr/local/distcc/bin:$PATH
and the change to the config/general.ent file would be:
<!ENTITY jlevel "-j4">
According to the distcc man page, this is called 'MASQUERADING'. This can
be both good and bad, however. Good in that if the makefile is a little
diddled up and it doesn't support the CC= environment variable, it can
still be parallel compiled. The bad news is, tho, if the package *can't* be
parallel compiled due to some other bug and you try to force it this way,
it may not build correctly. If you use the masquerading technique, do *not*
skip any testing phases of the build!
=-=-=-=-=-=-=
This technique scales quite well, with 4 machines (of similar speed) you'll
get about a 3.7x faster compile time IIRC, so if you have more than one
machine to access on the network, by all means, use 'em! ;-) If you do, a
decent rule of thumb is to set the jlevel number to 2x the number of
computers you're using on the network.
[[ If any of the computers are dual processor machines, consider them as
two machines for the sake of the jlevel -j number. The LFS LiveCD does
support SMP, so you can use all that horsepower! ]]
Of course, these commands are your friend: ;-)
distcc --help
distccd --help
man distcc
man distccd
More webpages on distcc:
http://ldp.paradoxical.co.uk/LDP/LGNET/current/simpson.html
http://www-128.ibm.com/developerworks/linux/library/l-distcc.html
Well, back to work... Hope this helps!
Laterz,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | Anarchy doesn't scale well. -- Me
[EMAIL PROTECTED] |
SysAdmin, Iceberg Computers
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