| Re: [eigen] glibc's malloc (x86-64) 16 byte aligned? |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] glibc's malloc (x86-64) 16 byte aligned?
- From: Rohit Garg <rpg.314@xxxxxxxxx>
- Date: Mon, 25 Jan 2010 23:40:36 +0530
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On Mon, Jan 25, 2010 at 11:32 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
> uuuuhhhhh.....
>
> indeed a quick test program shows that they are right... all my
> pointers are 16 byte aligned...
>
> Did that change in a recent version of glibc???
Probably.
>
> i'm using glibc 2.11.1.
I am on 2.10.1.
>
> Benoit
>
> 2010/1/25 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>:
>> oh!
>> i didn't read correctly - "(or sixteen on 64-bit systems)"
>>
>> I think that's an error on their part. Here on linux x86-64 that's
>> definitely not the case.
>>
>> Benoit
>>
>> 2010/1/25 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>:
>>> I don't understand?
>>> on linux x86-64, malloc only returns 8-byte aligned pointers, and this
>>> page confirms it.
>>> Benoit
>>>
>>> 2010/1/25 Rohit Garg <rpg.314@xxxxxxxxx>:
>>>> Hi all,
>>>>
>>>> http://www.gnu.org/s/libc/manual/html_node/Aligned-Memory-Blocks.html
>>>>
>>>> I was quite surprised to come across this. I never knew this was the
>>>> case. I wrote a quick, dirty, non-comprehensive, non-exhaustive test
>>>> and all of the malloc'ed pointers were 16 byte aligned.
>>>>
>>>> May be it's worth trying to run the eigen's test suite on linux x86-64
>>>> assuming that the malloc is 16 byte aligned?
>>>>
>>>> Your thoughts?
>>>>
>>>> --
>>>> Rohit Garg
>>>>
>>>> http://rpg-314.blogspot.com/
>>>>
>>>> Senior Undergraduate
>>>> Department of Physics
>>>> Indian Institute of Technology
>>>> Bombay
>>>>
>>>>
>>>>
>>>
>>
>
>
>
--
Rohit Garg
http://rpg-314.blogspot.com/
Senior Undergraduate
Department of Physics
Indian Institute of Technology
Bombay