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Subject: Re: [hwloc-devel] [hwloc-svn] svn:hwloc r3046
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-01-18 17:56:55


I took the liberty of committing this in r3090.

On Jan 18, 2011, at 2:00 PM, Jeff Squyres wrote:

> On Jan 12, 2011, at 10:10 AM, Samuel Thibault wrote:
>
>> This is not what I meant: hwloc_alloc_membind_policy's purpose is only
>> to allocate bound memory. It happens that hwloc_alloc_membind_policy
>> _may_ change the process policy in order to be able to bind memory
>> at all (when the underlying OS does not have a directed allocation
>> primitive), but that's not necessary. If hwloc can simply call a
>> directed allocation primitive, it will do it. If the OS doesn't support
>> binding at all, then hwloc will just allocate memory.
>
> How's this?
>
> * Setting this policy will cause the OS to try to bind a new memory
> * allocation to the specified set. As a side effect, some operating
> * systems may change the current memory binding policy; others may
> * simply ignore the policy (i.e., not bind the new memory allocation
> * at all). Note that since HWLOC_MEMBIND_STRICT was not specified,
> * failures to bind will not be reported -- generally, only memory
> * allocation failures will be reported (e.g., even a plain malloc()
> * would have failed with ENOMEM).
>
>>> + HWLOC_MEMBIND_INTERLEAVE = 3, /**< \brief Allocate memory on
>>
>> This is not really correct: if the threads were splitting the memory
>> amongst themselves, FIRSTTOUCH should be used instead, to migrate pages
>> close to where they are referenced from. I have rephrased that
>
> What's a good simple example scenario when it would be good to use INTERLEAVE, then?
>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
>

-- 
Jeff Squyres
jsquyres_at_[hidden]
For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/