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.buildinfo

@@ -1,4 +1,4 @@
 # Sphinx build info version 1
 # This file hashes the configuration used when building these files. When it is not found, a full rebuild will be done.
-config: d8862bc609545a59cb0d75fc5dbd55e6
+config: 658c1c056ff9c095d520e8ee5f5c269f
 tags: 645f666f9bcd5a90fca523b33c5a78b7

_sources/contents.rst.txt

@@ -22,3 +22,9 @@ Indices and tables
 * :ref:`genindex`
 * :ref:`search`
 * :ref:`glossary`
+
+
+Bibliography
+============
+
+.. bibliography::

_sources/src/Preliminaries/what_makes_fast_hs.rst.txt

@@ -142,10 +142,21 @@ Excessive Pointer Chasing
 What is Excessive Pointer Chasing
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Excessive pointer chasing is the enemy of any high performance Haskell program,
-and presents itself in various forms; most of which Haskeller's are familiar
-with to some degree. These include memory leaks during folds (strict and lazy),
-for example [#]_:
+Excessive pointer chasing is a form of superfluous computation; our program is
+doing more work than it needs in order to compute the result. It occurs anytime
+our programs dereference a pointer to retrieve a value instead of just
+referencing the value itself, thereby creating an extra layer of unnecessary
+indirection. In Haskell programs this most often occurs when we write programs
+without thinking about their memory representation; and especially around
+laziness. As such, most of these instances are well known and have floated
+around the community for some time.
+
+
+How does excessive pointer chasing slow down runtime performance?
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The classic example of excessive pointer chasing is memory leaks that result
+from folds that are overly lazy, for example [#]_:
 
 .. code-block:: haskell
    :caption: mean, calculated with a lazy left fold
@@ -219,16 +230,32 @@ that each ``Counter`` holds a pointer to an ``Int`` on the heap *not* a pointer
 to an ``Int`` directly. We can instruct GHC remove the heap indirection with the
 `unpack
 <https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/exts/pragmas.html?highlight=unpack#unpack-pragma>`_
+pragma and a bang pattern:
 
+.. code-block:: haskell
 
+   data Counter = Counter {-# UNPACK -#} !Int
 
-
+This pragma instructs GHC to store the contents of ``Int`` directly in the
+``Counter`` constructor, rather than storing a pointer to an ``Int`` on the heap
+in the constructor. We'll return to these fixes in the :ref:`Excessive Pointer
+Chasing` section.
 
 .. _canonical-closure-alloc:
 
 Excessive Closure Allocation
 ----------------------------
 
+What is Excessive Closure Allocation
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+xcessive :term:`Closure` allocation is :cite:p:`GHCInliner` and :cite:t:`GHCInliner`
+
+
+
+How does Excessive Closure Allocation slow down runtime performance
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 .. _canonical-domain-modeling:
 
 Poor Domain Modeling

_sources/src/glossary.rst.txt

@@ -16,20 +16,20 @@ Glossary
       <https://en.wikipedia.org/wiki/Lambda_calculus_definition#Weak_head_normal_form>`_
       for more.
 
-   Boxed Value
+   Boxed : Levity
       A Boxed value is a value that is represented by a pointer to the heap.
 
-   Unboxed Value
+   Unboxed : Levity
       An UnBoxed value is a value that is represented by the value itself.
       UnBoxed values therefore cannot be lazy, like boxed values.
 
-   Lifted Type
+   Lifted : Levity
       A Lifted type is a type that contains the value :math:`\bot`;
       which represents non-terminating computation. For example, the ``Bool``
       type is a set with three values: ``True``, ``False``, and :math:`\bot`.
       Therefore ``Bool`` is a Lifted type.
 
-   Unlifted Type
+   Unlifted : Levity
       An Unlifted type is a type where :math:`\bot` *is not* an element of that type.
 
    Thunk

contents.html

@@ -204,9 +204,14 @@ <h1>Welcome to Haskell Optimization Handbook<a class="headerlink" href="#welcome
 </li>
 <li class="toctree-l2"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#excessive-pointer-chasing">Excessive Pointer Chasing</a><ul>
 <li class="toctree-l3"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#what-is-excessive-pointer-chasing">What is Excessive Pointer Chasing</a></li>
+<li class="toctree-l3"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#how-does-excessive-pointer-chasing-slow-down-runtime-performance">How does excessive pointer chasing slow down runtime performance?</a></li>
+</ul>
+</li>
+<li class="toctree-l2"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#excessive-closure-allocation">Excessive Closure Allocation</a><ul>
+<li class="toctree-l3"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#what-is-excessive-closure-allocation">What is Excessive Closure Allocation</a></li>
+<li class="toctree-l3"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#how-does-excessive-closure-allocation-slow-down-runtime-performance">How does Excessive Closure Allocation slow down runtime performance</a></li>
 </ul>
 </li>
-<li class="toctree-l2"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#excessive-closure-allocation">Excessive Closure Allocation</a></li>
 <li class="toctree-l2"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#poor-domain-modeling">Poor Domain Modeling</a></li>
 <li class="toctree-l2"><a class="reference internal" href="src/Preliminaries/what_makes_fast_hs.html#references">References</a></li>
 </ul>
@@ -221,6 +226,16 @@ <h1>Indices and tables<a class="headerlink" href="#indices-and-tables" title="Pe
 <li><p><a class="reference internal" href="search.html"><span class="std std-ref">Search Page</span></a></p></li>
 <li><p><a class="reference internal" href="src/glossary.html#glossary"><span class="std std-ref">Glossary</span></a></p></li>
 </ul>
+</section>
+<section id="bibliography">
+<h1>Bibliography<a class="headerlink" href="#bibliography" title="Permalink to this headline">¶</a></h1>
+<div class="docutils container" id="id1">
+<div class="citation" id="id2" role="doc-biblioentry">
+<span class="label"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></span>
+<p>Simon Peyton Jones and Simon Marlow. Secrets of the glasgow haskell compiler inliner. <em>J. Funct. Program.</em>, 12(5):393–434, jul 2002. URL: <a class="reference external" href="https://doi.org/10.1017/S0956796802004331">https://doi.org/10.1017/S0956796802004331</a>, <a class="reference external" href="https://doi.org/10.1017/S0956796802004331">doi:10.1017/S0956796802004331</a>.</p>
+</div>
+</div>
+</div>
 </section>
 
 

genindex.html

@@ -180,34 +180,32 @@
 <h1 id="index">Index</h1>
 
 <div class="genindex-jumpbox">
- <a href="#B"><strong>B</strong></a>
- | <a href="#C"><strong>C</strong></a>
- | <a href="#L"><strong>L</strong></a>
+ <a href="#C"><strong>C</strong></a>
+ | <a href="#Levity"><strong>Levity</strong></a>
  | <a href="#Normal Forms"><strong>Normal Forms</strong></a>
  | <a href="#T"><strong>T</strong></a>
- | <a href="#U"><strong>U</strong></a>
 
 </div>
-<h2 id="B">B</h2>
+<h2 id="C">C</h2>
 <table style="width: 100%" class="indextable genindextable"><tr>
   <td style="width: 33%; vertical-align: top;"><ul>
-      <li><a href="src/glossary.html#term-Boxed-Value"><strong>Boxed Value</strong></a>
+      <li><a href="src/glossary.html#term-Closure"><strong>Closure</strong></a>
 </li>
   </ul></td>
 </tr></table>
 
-<h2 id="C">C</h2>
+<h2 id="Levity">Levity</h2>
 <table style="width: 100%" class="indextable genindextable"><tr>
   <td style="width: 33%; vertical-align: top;"><ul>
-      <li><a href="src/glossary.html#term-Closure"><strong>Closure</strong></a>
+      <li><a href="src/glossary.html#term-Boxed"><strong>Boxed</strong></a>
+</li>
+      <li><a href="src/glossary.html#term-Lifted"><strong>Lifted</strong></a>
 </li>
   </ul></td>
-</tr></table>
-
-<h2 id="L">L</h2>
-<table style="width: 100%" class="indextable genindextable"><tr>
   <td style="width: 33%; vertical-align: top;"><ul>
-      <li><a href="src/glossary.html#term-Lifted-Type"><strong>Lifted Type</strong></a>
+      <li><a href="src/glossary.html#term-Unboxed"><strong>Unboxed</strong></a>
+</li>
+      <li><a href="src/glossary.html#term-Unlifted"><strong>Unlifted</strong></a>
 </li>
   </ul></td>
 </tr></table>
@@ -228,18 +226,6 @@ <h2 id="T">T</h2>
   </ul></td>
 </tr></table>
 
-<h2 id="U">U</h2>
-<table style="width: 100%" class="indextable genindextable"><tr>
-  <td style="width: 33%; vertical-align: top;"><ul>
-      <li><a href="src/glossary.html#term-Unboxed-Value"><strong>Unboxed Value</strong></a>
-</li>
-  </ul></td>
-  <td style="width: 33%; vertical-align: top;"><ul>
-      <li><a href="src/glossary.html#term-Unlifted-Type"><strong>Unlifted Type</strong></a>
-</li>
-  </ul></td>
-</tr></table>
-
 
 
           </div>