[[project @ 2005-11-17 10:12:26 by simonmar]
simonmar**20051117101226
 Separate the documentation for Concurrent Haskell from that for
 Parallel Haskell, and put a big note at the top of the Parallel
 Haskell section pointing to the GPH site.
] {
hunk ./ghc/docs/users_guide/using.xml 1481
-<title>Using Concurrent Haskell</title>
+    <title>Using Concurrent Haskell</title>
+    <indexterm><primary>Concurrent Haskell</primary><secondary>using</secondary></indexterm>
hunk ./ghc/docs/users_guide/using.xml 1484
-	     <indexterm><primary>Concurrent Haskell&mdash;use</primary></indexterm>
+    <para>GHC supports Concurrent Haskell by default, without requiring a
+      special option or libraries compiled in a certain way.  To get access to
+      the support libraries for Concurrent Haskell, just import
+      <ulink
+	url="../libraries/base/Control-Concurrent.html"><literal>Control.Concurrent</literal></ulink>.  More information on Concurrent Haskell is provided in the documentation for that module.</para>
hunk ./ghc/docs/users_guide/using.xml 1490
-<para>
-GHC supports Concurrent Haskell by default, without requiring a
-special option or libraries compiled in a certain way.  To get access
-to the support libraries for Concurrent Haskell, just import
-<literal>Control.Concurrent</literal> (details are in the accompanying
-library documentation).</para>
-
-<para>
-RTS options are provided for modifying the behaviour of the threaded
-runtime system.  See <xref linkend="parallel-rts-opts"/>.
-</para>
-
-<para>
-Concurrent Haskell is described in more detail in the documentation
-for the <literal>Control.Concurrent</literal> module.
-</para>
+    <para>The following RTS option(s) affect the behaviour of Concurrent
+      Haskell programs:<indexterm><primary>RTS options, concurrent</primary></indexterm></para>
hunk ./ghc/docs/users_guide/using.xml 1493
-</sect1>
+    <variablelist>
+      <varlistentry>
+	<term><option>-C<replaceable>s</replaceable></option></term>
+	<listitem>
+	  <para><indexterm><primary><option>-C<replaceable>s</replaceable></option></primary><secondary>RTS option</secondary></indexterm>
+	    Sets the context switch interval to <replaceable>s</replaceable>
+	    seconds.  A context switch will occur at the next heap block
+	    allocation after the timer expires (a heap block allocation occurs
+	    every 4k of allocation).  With <option>-C0</option> or
+	    <option>-C</option>, context switches will occur as often as
+	    possible (at every heap block allocation).  By default, context
+	    switches occur every 20ms.  Note that GHC's internal timer ticks
+	    every 20ms, and the context switch timer is always a multiple of
+	    this timer, so 20ms is the maximum granularity available for timed
+	    context switches.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </sect1>
hunk ./ghc/docs/users_guide/using.xml 1517
-<indexterm><primary>parallel Haskell&mdash;use</primary></indexterm>
-</para>
-
-<para>
-&lsqb;You won't be able to execute parallel Haskell programs unless PVM3
+<indexterm><primary>Parallel Haskell</primary><secondary>using</secondary></indexterm>
+&lsqb;NOTE: GHC does not support Parallel Haskell by default, you need to
+      obtain a special version of GHC from the <ulink
+	url="http://www.cee.hw.ac.uk/~dsg/gph/">GPH</ulink> site.  Also,
+you won't be able to execute parallel Haskell programs unless PVM3
hunk ./ghc/docs/users_guide/using.xml 1530
-parallel</literal> into your Haskell modules.
+Control.Parallel</literal> into your Haskell modules.
hunk ./ghc/docs/users_guide/using.xml 1662
-<option>-qP</option><indexterm><primary>-qP RTS option (concurrent, parallel)</primary></indexterm> RTS option.  The
+<option>-qP</option><indexterm><primary>-qP RTS option</primary></indexterm> RTS option.  The
hunk ./ghc/docs/users_guide/using.xml 1707
-<title>RTS options for Concurrent/parallel Haskell
+<title>RTS options for Parallel Haskell
hunk ./ghc/docs/users_guide/using.xml 1711
-<indexterm><primary>RTS options, concurrent</primary></indexterm>
hunk ./ghc/docs/users_guide/using.xml 1712
-<indexterm><primary>Concurrent Haskell&mdash;RTS options</primary></indexterm>
hunk ./ghc/docs/users_guide/using.xml 1718
-for concurrent/parallel execution.
+for parallel execution.
hunk ./ghc/docs/users_guide/using.xml 1773
-(paraLLEL ONLY) Limit the thread pool size, i.e. the number of concurrent
+(paraLLEL ONLY) Limit the thread pool size, i.e. the number of 
}