Revert "poky: subtree update:b23aa6b753..ad30a6d470"

This reverts commit af5e4ef732faedf66c6dc1756432e9de2ac72988.

This commit introduced openbmc/openbmc#3720 and no solution has been
forthcoming. Revert until we can get to the bottom of this.

Change-Id: I2fb0d81eb26cf3dadb2f2abdd1a1bb7a95eaf03c
diff --git a/poky/documentation/profile-manual/profile-manual-examples.xml b/poky/documentation/profile-manual/profile-manual-examples.xml
new file mode 100644
index 0000000..91e06fc
--- /dev/null
+++ b/poky/documentation/profile-manual/profile-manual-examples.xml
@@ -0,0 +1,40 @@
+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<chapter id='profile-manual-examples'>
+
+<title>Real-World Examples</title>
+
+<para>
+    This chapter contains real-world examples.
+</para>
+
+<section id='slow-write-speed-on-live-images'>
+    <title>Slow Write Speed on Live Images</title>
+
+    <para>
+        In one of our previous releases (denzil), users noticed that booting
+        off of a live image and writing to disk was noticeably slower.
+        This included the boot itself, especially the first one, since first
+        boots tend to do a significant amount of writing due to certain
+        post-install scripts.
+    </para>
+
+    <para>
+        The problem (and solution) was discovered by using the Yocto tracing
+        tools, in this case 'perf stat', 'perf script', 'perf record'
+        and 'perf report'.
+    </para>
+
+    <para>
+        See all the unvarnished details of how this bug was diagnosed and
+        solved here: Yocto Bug #3049
+    </para>
+</section>
+
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->