From 740ecf83a6cec93fc40a3ced1f7d8825a39516e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 20 Apr 2015 14:59:19 +0200
Subject: compile: Teach 'time' option to show three significant decimals
The 'time' option currently uses statistics(runtime) to measure
execution times. Typically, statistics(runtime) only returns
result with two significant figures.
Use the new erlang:monotonic_time/0 function to get three
significant figures.
---
lib/compiler/src/compile.erl | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index c45c9a1a29..635d322cc9 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -320,15 +320,14 @@ fold_comp([{Name,Pass}|Ps], Run, St0) ->
fold_comp([], _Run, St) -> {ok,St}.
run_tc({Name,Fun}, St) ->
- Before0 = statistics(runtime),
+ T1 = erlang:monotonic_time(),
Val = (catch Fun(St)),
- After0 = statistics(runtime),
- {Before_c, _} = Before0,
- {After_c, _} = After0,
+ T2 = erlang:monotonic_time(),
+ Elapsed = erlang:convert_time_unit(T2 - T1, native, milli_seconds),
Mem0 = erts_debug:flat_size(Val)*erlang:system_info(wordsize),
Mem = lists:flatten(io_lib:format("~.1f kB", [Mem0/1024])),
- io:format(" ~-30s: ~10.2f s ~12s\n",
- [Name,(After_c-Before_c) / 1000,Mem]),
+ io:format(" ~-30s: ~10.3f s ~12s\n",
+ [Name,Elapsed/1000,Mem]),
Val.
comp_ret_ok(#compile{code=Code,warnings=Warn0,module=Mod,options=Opts}=St) ->
--
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