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31 lines
1.5 KiB
XML
31 lines
1.5 KiB
XML
<sect1 id="ch02-aboutsbus">
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<title>About SBUs</title>
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<?dbhtml filename="aboutsbus.html" dir="chapter02"?>
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<para>SBUs are <emphasis>Static Bash Units</emphasis> and they are our way
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of identifying how long a package takes to compile. Why don't we use normal
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times like anybody else?</para>
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<para>The biggest problem is that times cannot be acurate, not even a
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little bit. So many people install LFS on so many different systems, the
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times it takes to compile something varies too much. One package may take
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20 minutes on one system, but that same package may take 3 days on another
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(this is not an exaggeration). So instead we've come up with a
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<emphasis>Static Bash Unit</emphasis> or <emphasis>SBU</emphasis>.</para>
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<para>It works like this: the very first package you compile in this book
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is Bash in Chapter 5 and it'll be statically linked. The time it takes to
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compile this package will be the basis and called the SBU. All other
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compile times are relative to the time it takes to install Bash. For
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example, GCC-3.2 takes about 9.5 SBUs and it's proven that this number is
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fairly consistent among a lot of different systems. So multiply 9.5 by the
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number of seconds it takes for Bash to install (the SBU value) and you get
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a close approximation of how long GCC will take on your system.</para>
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<para>Note: SBUs don't work on SMP machines. We've seen that SBUs don't
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work well on SMP based machines. So all bets are off if you're lucky enough
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to have an SMP setup.</para>
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</sect1>
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