Changeset 82c65b7 for introduction/important

Timestamp:

06/07/2015 12:57:42 AM (9 years ago)

Author:

Bruce Dubbs <bdubbs@…>

Branches:

10.0, 10.1, 11.0, 11.1, 11.2, 11.3, 12.0, 12.1, 7.10, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 9.0, 9.1, basic, bdubbs/svn, elogind, kea, ken/TL2024, ken/inkscape-core-mods, ken/tuningfonts, lazarus, lxqt, nosym, perl-modules, plabs/newcss, plabs/python-mods, python3.11, qt5new, rahul/power-profiles-daemon, renodr/vulkan-addition, trunk, upgradedb, xry111/intltool, xry111/llvm18, xry111/soup3, xry111/test-20220226, xry111/xf86-video-removal

Children:

ff6e37c8

Parents:

69a39a2

Message:

Update to v4l-utils-1.6.3.
Add 'Using Multiple Processors' to Notes on Building Software.
Minor grammar and spacing corrections.

git-svn-id: svn://svn.linuxfromscratch.org/BLFS/trunk/BOOK@16089 af4574ff-66df-0310-9fd7-8a98e5e911e0

File:

• introduction/important/building-notes.xml (modified) (2 diffs)

introduction/important/building-notes.xml

@@ -7 +7 @@
 
 <sect1 id="unpacking">
-  <?dbhtml filename="unpacking.html"?>
+  <?dbhtml filename="notes-on-building.html"?>
 
   <sect1info>
@@ -133 +133 @@
     <replaceable>&lt;command&gt;</replaceable> is returned as the result and not the
     result of the <command>tee</command> command.</para>
+
+  </sect2>
+
+  <sect2 id="parallel-builds" xreflabel="Using Multiple Processors">
+    <title>Using Multiple Processors</title>
+
+    <para>For many modern systems with multiple processors (or cores) the
+    compilation time for a package can be reduced by performing a "parallel
+    make" by either setting an environment variable or telling the make program
+    how many processors are available. For instance, a Core2Duo can support two
+    simultaneous processes with: </para>
+
+    <screen><userinput>export MAKEFLAGS='-j2'</userinput></screen>
+
+    <para>or just building with:</para>
+
+    <screen><userinput>make -j2</userinput></screen>
+
+    <para>Generally the number of processes should not exceed the number of
+    cores supported by the CPU.  To list the processors on your
+    system, issue: <userinput>grep processor /proc/cpuinfo</userinput>.
+    </para>
+
+    <para>In some cases, using multiple processors may result in a 'race'
+    condition where the success of the build depends on the order of the
+    commands run by the <command>make</command> program.  For instance, if an
+    execuatable needs File A and File B, attempting to link the program before
+    one of the dependent components is available will result in a failure.
+    This condition usually arises because the upstream developer has not
+    properly designated all the prerequsites needed to accomplish a step in the
+    Makefile.</para>
+
+    <para>If this occurs, the best way to proceed is to drop back to a
+    single processor build.  Adding '-j1' to a make command will override
+    the similar setting in the MAKEFLAGS environment variable.</para>
 
   </sect2>