From eea5f896780e07f7ca76685061d01e7be5a7abaa Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang-solutions.com>
Date: Thu, 11 Sep 2014 18:26:26 +0200
Subject: erts, kernel: Add os:perf_counter function

The perf_counter is a very very cheap and high resolution timer
that can be used to timestamp system events. It does not have
monoticity guarantees, but should on most OS's expose a monotonous
time.

A special instruction has been created for this counter to further
speed up fetching it.

OTP-12908
---
 erts/doc/src/erlang.xml | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'erts/doc')

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index d0d35ea25f..6915b35fcb 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -131,6 +131,17 @@
 	  </note>
 	  </item>
 
+	  <tag><c>perf_counter</c></tag>
+	  <item><p>Symbolic representation of the performance counter
+          time unit used by the Erlang runtime system.</p>
+
+          <p>The <c>perf_counter</c> time unit behaves much in the same way
+          as the <c>native</c> time unit. That is it might differ inbetween
+          run-time restarts. You get values of this type by calling
+          <seealso marker="kernel:os#perf_counter/0"><c>os:perf_counter()</c></seealso>
+          </p>
+          </item>
+
 	</taglist>
 
 	<p>The <c>time_unit/0</c> type may be extended. Use
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