X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=docs%2Fusers_guide%2Fruntime_control.xml;h=95365bacce9af76da4febe616699e3682e307e94;hb=22010da1a4517529292991ab550bba6d3c3e7523;hp=e89f340430ddf77e7e6504898cc2db6549d35deb;hpb=78b620de24ceb4621cead67bd642f72749b41052;p=ghc-hetmet.git

diff --git a/docs/users_guide/runtime_control.xml b/docs/users_guide/runtime_control.xml
index e89f340..95365ba 100644
--- a/docs/users_guide/runtime_control.xml
+++ b/docs/users_guide/runtime_control.xml
@@ -108,6 +108,14 @@
          the <option>-C</option> or <option>-i</option> options.
          However, setting <option>-V</option> is required in order to
          increase the resolution of the time profiler.</para>
+
+         <para>Using a value of zero disables the RTS clock
+         completetly, and has the effect of disabling timers that
+         depend on it: the context switch timer and the heap profiling
+         timer.  Context switches will still happen, but
+         deterministically and at a rate much faster than normal.
+         Disabling the interval timer is useful for debugging, because
+         it eliminates a source of non-determinism at runtime.</para>
        </listitem>
      </varlistentry>