From d927209aa36fe370eb4ecf0a081923b0b951458b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 20 Apr 2015 15:32:22 +0200
Subject: timer: Use monotonic_time/0 in tc/1,2,3

---
 lib/stdlib/src/timer.erl | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

(limited to 'lib/stdlib')

diff --git a/lib/stdlib/src/timer.erl b/lib/stdlib/src/timer.erl
index 19d803345e..c266177b4d 100644
--- a/lib/stdlib/src/timer.erl
+++ b/lib/stdlib/src/timer.erl
@@ -161,10 +161,11 @@ sleep(T) ->
       Time :: integer(),
       Value :: term().
 tc(F) ->
-    Before = os:timestamp(),
+    T1 = erlang:monotonic_time(),
     Val = F(),
-    After = os:timestamp(),
-    {now_diff(After, Before), Val}.
+    T2 = erlang:monotonic_time(),
+    Time = erlang:convert_time_unit(T2 - T1, native, micro_seconds),
+    {Time, Val}.
 
 %%
 %% Measure the execution time (in microseconds) for Fun(Args).
@@ -175,10 +176,11 @@ tc(F) ->
       Time :: integer(),
       Value :: term().
 tc(F, A) ->
-    Before = os:timestamp(),
+    T1 = erlang:monotonic_time(),
     Val = apply(F, A),
-    After = os:timestamp(),
-    {now_diff(After, Before), Val}.
+    T2 = erlang:monotonic_time(),
+    Time = erlang:convert_time_unit(T2 - T1, native, micro_seconds),
+    {Time, Val}.
 
 %%
 %% Measure the execution time (in microseconds) for an MFA.
@@ -190,10 +192,11 @@ tc(F, A) ->
       Time :: integer(),
       Value :: term().
 tc(M, F, A) ->
-    Before = os:timestamp(),
+    T1 = erlang:monotonic_time(),
     Val = apply(M, F, A),
-    After = os:timestamp(),
-    {now_diff(After, Before), Val}.
+    T2 = erlang:monotonic_time(),
+    Time = erlang:convert_time_unit(T2 - T1, native, micro_seconds),
+    {Time, Val}.
 
 %%
 %% Calculate the time difference (in microseconds) of two
-- 
cgit v1.2.3