# [pypy-svn] extradoc extradoc: replace one itemize by a sentence, which gives me enough space to resurrect the

Fri Apr 15 13:40:48 CEST 2011

Author: Carl Friedrich Bolz <cfbolz at gmx.de>
Changeset: r3518:0e0627c8d4c1
Date: 2011-04-15 13:40 +0200

Log:	replace one itemize by a sentence, which gives me enough space to
resurrect the meta-paragraph.

diff --git a/talk/icooolps2011/paper.tex b/talk/icooolps2011/paper.tex
--- a/talk/icooolps2011/paper.tex
+++ b/talk/icooolps2011/paper.tex
@@ -378,15 +378,10 @@
hand, if applied incorrectly they might lead to code bloat, thus making the
resulting program actually slower.

-For constant folding to work, two conditions need to be met:
-
-\begin{itemize}
-    \item the arguments of an operation actually need to all be constant,
-    i.e. statically known by the optimizer
-    \item the operation needs to be \emph{constant-foldable}, i.e. always yield
-    the same result given the same arguments.
-\end{itemize}
-
+For constant folding to work, two conditions need to be met: the arguments of
+an operation actually need to all be constant, i.e. statically known by the
+optimizer and the operation needs to be \emph{constant-foldable}, i.e. always
+yield the same result given the same arguments.
There is one kind of hint for both of these conditions.

@@ -395,7 +390,6 @@
It is worth clarifying what a constant'' is in this context.  A variable of
the trace is said to be constant if its value is statically known by the
optimizer.
-
The simplest example of constants are literal values, such as \texttt{1}.
However, the optimizer can statically know the value of a variable even if it
is not a constant in the original source code. For example, consider the
@@ -698,8 +692,8 @@
\subsection{Making Instance Attributes Faster Using Maps}

The first step in making \texttt{getattr} faster in our object model is to optimize
-away the dictionary lookups on the instances. The hints we have introduced in the
-two previous sections don't seem to help with the current object model. There is
+away the dictionary lookups on the instances. The hints of the previous section
+don't seem to help with the current object model. There is
no trace-elidable function to be seen, and the instance is not a candidate for promotion,
because there tend to be many instances.

@@ -749,7 +743,12 @@
between. This trace is already much better than
the original one. Now we are down from five dictionary lookups to just two.

-XXX separation of fast and slow-changing parts
+The technique to make instance lookups faster is applicable in more general
+cases. A more abstract view of maps is that of splitting a data-structure into
+an immutable part (\eg the map) and a part that changes (\eg the storage list).
+All the computation on the immutable part is trace-elidable so that only the
+manipulation of the quick-changing part remains in the trace after
+optimization.

\begin{figure}
\input{code/trace2.tex}
@@ -856,12 +855,6 @@

%\subsection{More General Patterns}
%
-%The techniques we used above to make instance and class lookups faster are
-%applicable in more general cases than the one we developed them for. A more
-%abstract view of maps is that of splitting a data-structure into an immutable part (\eg the map)
-%and a part that changes (\eg the storage list). All the computation on the
-%immutable part is trace-elidable so that only the manipulation of the quick-changing
-%part remains in the trace after optimization.
%
%Similarly, versions can be used to constant-fold arbitrary functions of large data
%structures. The version needs to be updated carefully every time the result of

diff --git a/talk/icooolps2011/jit-hints.pdf b/talk/icooolps2011/jit-hints.pdf
index f8a740101f3b8f4b2e95a30938567c5ae6d11c34..295a4bb35ae37f83812c8d212381354e07d8d44d
GIT binary patch
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