New syntax for GADT-style record declarations, and associated refactoring

[ghc-hetmet.git] / docs / users_guide / profiling.xml

diff --git a/docs/users_guide/profiling.xml b/docs/users_guide/profiling.xml
index 1b4dfa0..adb7a33 100644 (file)
--- a/docs/users_guide/profiling.xml
+++ b/docs/users_guide/profiling.xml
@@ -33,7 +33,9 @@
     <listitem>
       <para> Run your program with one of the profiling options, eg.
       <literal>+RTS -p -RTS</literal>.  This generates a file of
-      profiling information.</para>
+      profiling information.  Note that multi-processor execution
+      (e.g. <literal>+RTS -N2</literal>) is not supported while
+      profiling.</para>
       <indexterm><primary><option>-p</option></primary><secondary>RTS
       option</secondary></indexterm>
     </listitem>
@@ -264,6 +266,22 @@ MAIN                     MAIN             0    0.0   0.0    100.0 100.0
       far to the right as possible when parsing. (SCC stands for "Set
       Cost Centre").</para>
 
+      <para>Here is an example of a program with a couple of SCCs:</para>
+
+<programlisting>
+main :: IO ()
+main = do let xs = {-# SCC "X" #-} [1..1000000]
+          let ys = {-# SCC "Y" #-} [1..2000000]
+          print $ last xs
+          print $ last $ init xs
+          print $ last ys
+          print $ last $ init ys
+</programlisting>
+
+      <para>which gives this heap profile when run:</para>
+
+      <imagedata fileref="prof_scc"/>
+
     </sect2>
 
     <sect2 id="prof-rules">