diff --git a/chapter08/automake.xml b/chapter08/automake.xml
index 4fc1bd277..5d7541049 100644
--- a/chapter08/automake.xml
+++ b/chapter08/automake.xml
@@ -53,11 +53,14 @@
 
 <screen><userinput remap="make">make</userinput></screen>
 
-    <para> Using the -j4 make option speeds up the tests, even on systems with
-    only one processor, due to internal delays in individual tests.  To test
+    <para>Using four parallel jobs speeds up the tests, even on systems with
+    less logical cores, due to internal delays in individual tests.  To test
     the results, issue:</para>
 
-<screen><userinput remap="test">make -j4 check</userinput></screen>
+<screen><userinput remap="test">make <replaceable>-j$(($(nproc)&gt;4?$(nproc):4))</replaceable> check</userinput></screen>
+
+    <para>Replace <replaceable>$((...))</replaceable> with the number of
+    logical cores you want to use if you don't want to use all.</para>
 
     <para>The test t/subobj.sh is known to fail.</para>