纪秀峰]:erlang:now() os:timestamp() 比较_erlang:now() 与 os:timestamp() 区别-优快云博客

本文对比了Erlang中erlang:now()与os:timestamp()两个时间获取函数的性能，通过实验发现os:timestamp()函数在大量调用时表现出更好的效率。

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纪秀峰]:erlang:now() os:timestamp() 比较

受影响的文件:
    benchmark/src/now_timestamp.erl

master

commit ceefc934e92fc3ffd66683012d0e306be175302d 1 parent 16cbbe7

jixiuf authored January 25, 2013

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+32 −0  benchmark/src/now_timestamp.erl

32  benchmark/src/now_timestamp.erl

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+%%%-------------------------------------------------------------------
+%%% @author 纪秀峰 <jixiuf@gmail.com>
+%%% @doc
+%%%
+%%% @end
+%%% Created : 2013-01-25 10:21 by 纪秀峰 <jixiuf@gmail.com>
+%%%-------------------------------------------------------------------
+-module(now_timestamp).
+-export([test/1]).
+
+%% 测erlang:now() 与os:timestamp() 哪个速度更快
+%% (emacs@jf.org)22> now_timestamp:test(10000).
+%% erlang:now():{940,ok}
+%% os:timestamp():{522,ok}
+%% 测试结果显示 os:timestamp() 较快
+
+test(N)->
+ T=timer:tc(fun () -> now_benchmark(N) end),
+ io:format("erlang:now():~p~n",[T]) ,
+ T2=timer:tc(fun () -> os_timestamp_benchmark(N) end),
+ io:format("os:timestamp():~p~n",[T2])
+ .
+now_benchmark(0)->ok;
+now_benchmark(N)->
+ now(),
+ now_benchmark(N-1)
+ .
+os_timestamp_benchmark(0)->ok;
+os_timestamp_benchmark(N)->
+ os:timestamp(),
+ os_timestamp_benchmark(N-1)
+ .
 
  