X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fdocs%2Fusers_guide%2Fruntime_control.xml;h=daed07cee340c6c5a3d8ff764854dcbb98c4c55f;hb=76c0086f090327eecaf510de8bc4efc4dee996dc;hp=ee62855d2f6b32358b90f9262207012f9b174118;hpb=092d79172d9e27e329481aae18b4a931619ab81c;p=ghc-hetmet.git

diff --git a/ghc/docs/users_guide/runtime_control.xml b/ghc/docs/users_guide/runtime_control.xml
index ee62855..daed07c 100644
--- a/ghc/docs/users_guide/runtime_control.xml
+++ b/ghc/docs/users_guide/runtime_control.xml
@@ -80,7 +80,7 @@
 </screen>
 
     <para>RTS options taken from the <envar>GHCRTS</envar> environment
-    variable can be overriden by options given on the command
+    variable can be overridden by options given on the command
     line.</para>
 
   </sect2>
@@ -245,6 +245,39 @@
 
       <varlistentry>
 	<term>
+	  <option>-I</option><replaceable>seconds</replaceable>
+	  <indexterm><primary><option>-H</option></primary>
+	    <secondary>RTS option</secondary>
+	  </indexterm>
+	  <indexterm><primary>idle GC</primary>
+	  </indexterm>
+	  </term>
+	<listitem>
+	  <para>(default: 0.3) In the threaded and SMP versions of the RTS (see
+	    <option>-threaded</option>, <xref linkend="options-linker" />), a
+	    major GC is automatically performed if the runtime has been idle
+	    (no Haskell computation has been running) for a period of time.
+	    The amount of idle time which must pass before a GC is performed is
+	    set by the <option>-I</option><replaceable>seconds</replaceable>
+	    option.  Specifying <option>-I0</option> disables the idle GC.</para>
+
+	  <para>For an interactive application, it is probably a good idea to
+	    use the idle GC, because this will allow finalizers to run and
+	    deadlocked threads to be detected in the idle time when no Haskell
+	    computation is happening.  Also, it will mean that a GC is less
+	    likely to happen when the application is busy, and so
+	    responsiveness may be improved.   However, if the amount of live data in
+	    the heap is particularly large, then the idle GC can cause a
+	    significant delay, and too small an interval could adversely affect
+	    interactive responsiveness.</para>
+
+	  <para>This is an experimental feature, please let us know if it
+	    causes problems and/or could benefit from further tuning.</para>
+	</listitem>
+      </varlistentry>
+
+      <varlistentry>
+	<term>
          <option>-k</option><replaceable>size</replaceable>
          <indexterm><primary><option>-k</option></primary><secondary>RTS option</secondary></indexterm>
          <indexterm><primary>stack, minimum size</primary></indexterm>
@@ -344,13 +377,20 @@
 
       <varlistentry>
 	<term>
-          <option>-t</option>
+          <option>-t<replaceable>file</replaceable></option>
           <indexterm><primary><option>-t</option></primary><secondary>RTS option</secondary></indexterm>
         </term>
 	<listitem>
 	  <para>Write a one-line GC stats summary after running the
 	  program.  This output is in the same format as that produced
 	  by the <option>-Rghc-timing</option> option.</para>
+
+	  <para>As with <option>-s</option>, the default
+          <replaceable>file</replaceable> is
+          <filename><replaceable>program</replaceable>.stat</filename>. The
+          <replaceable>file</replaceable> <constant>stderr</constant>
+          is treated specially, with the output really being sent to
+          <constant>stderr</constant>.</para>
 	</listitem>
       </varlistentry>
     </variablelist>