[erlang-questions] native

Tony Rogvall <>
Tue Sep 11 16:19:47 CEST 2012


On 11 sep 2012, at 16:22, Kostis Sagonas <> wrote:

> On 09/11/2012 09:06 AM, Tony Rogvall wrote:
>> 
>> On 10 sep 2012, at 19:03, Thomas Lindgren <
>> <mailto:>> wrote:
>> 
>>>> ________________________________
>>>> From: Kostis Sagonas < <mailto:>>
>>>> 
>>>> 
>>>> I do not know why Thomas thinks that HiPE should be able to
>>>> confortably beat BEAM on this sort of code (care to elaborate?). From
>>>> a brief glance it seems to me that the code spends a lot of time in
>>>> BIFs written in C (most notably list_to_tuple/1 and element/2, but
>>>> also trunc/1, abs/1 and math:sin/1. All of these are outside the
>>>> reach of the native code compiler.
>>> 
>>> 
>>> The regular MD5 algorithm is basically a loop doing lots of integer
>>> arithmetic and bit operations as well as accessing a few arrays. This
>>> ought on the face of it to be quite amenable to native code
>>> compilation. I'm amazed that the implementation Tony used managed to
>>> get trunc/abs/sin into the inner loop, but that might as you say well
>>> explain the problem.
>> 
>> My goal with this implementation was not speed. I really wanted
>> something simple to look at. erlang:md5 already exists, and
>> there is no point competing with that. I just compiled it native for
>> fun. So do not be amazed! :-)
>> But as shown by kostis and others it looks like it is my computer that
>> behaves badly, I will have a look.
> 
> I investigated this further.  Can it be that your computer runs in 32-bit mode?  If so, I can explain what is happening.
> 
Yes.

/Tony

> Kostis

"Installing applications can lead to corruption over time. Applications gradually write over each other's libraries, partial upgrades occur, user and system errors happen, and minute changes may be unnoticeable and difficult to fix"



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