Open MPI logo

Hardware Locality Users' Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Hardware Locality Users mailing list

Subject: Re: [hwloc-users] Thread binding problem
From: Gabriele Fatigati (g.fatigati_at_[hidden])
Date: 2012-09-05 09:56:16


An update:

placing strerror(errno) after hwloc_set_area_membind_nodeset gives:
"Cannot allocate memory"

2012/9/5 Gabriele Fatigati <g.fatigati_at_[hidden]>

> Hi,
>
> I've noted that hwloc_set_area_membind_nodeset return -1 but errno is not
> equal to EXDEV or ENOSYS. I supposed that these two case was the two unique
> possibly.
>
> From the hwloc documentation:
>
> -1 with errno set to ENOSYS if the action is not supported
> -1 with errno set to EXDEV if the binding cannot be enforced
>
>
> Any other binding failure reason? The memory available is enought.
>
> 2012/9/5 Brice Goglin <Brice.Goglin_at_[hidden]>
>
>> Hello Gabriele,
>>
>> The only limit that I would think of is the available physical memory on
>> each NUMA node (numactl -H will tell you how much of each NUMA node memory
>> is still available).
>> malloc usually only fails (it returns NULL?) when there no *virtual*
>> memory anymore, that's different. If you don't allocate tons of terabytes
>> of virtual memory, this shouldn't happen easily.
>>
>> Brice
>>
>>
>>
>>
>> Le 05/09/2012 14:27, Gabriele Fatigati a écrit :
>>
>> Dear Hwloc users and developers,
>>
>>
>> I'm using hwloc 1.4.1 on a multithreaded program in a Linux platform,
>> where each thread bind many non contiguos pieces of a big matrix using in a
>> very intensive way hwloc_set_area_membind_nodeset function:
>>
>> hwloc_set_area_membind_nodeset(topology, punt+offset, len, nodeset,
>> HWLOC_MEMBIND_BIND, HWLOC_MEMBIND_THREAD | HWLOC_MEMBIND_MIGRATE);
>>
>> Binding seems works well, since the returned code from function is 0
>> for every calls.
>>
>> The problems is that after binding, a simple little new malloc fails,
>> without any apparent reason.
>>
>> Disabling memory binding, the allocations works well. Is there any
>> knows problem if hwloc_set_area_membind_nodeset is used intensively?
>>
>> Is there some operating system limit for memory pages binding?
>>
>> Thanks in advance.
>>
>> --
>> Ing. Gabriele Fatigati
>>
>> HPC specialist
>>
>> SuperComputing Applications and Innovation Department
>>
>> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
>>
>> www.cineca.it Tel: +39 051 6171722
>>
>> g.fatigati [AT] cineca.it
>>
>>
>> _______________________________________________
>> hwloc-users mailing listhwloc-users_at_[hidden]http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users
>>
>>
>>
>
>
> --
> Ing. Gabriele Fatigati
>
> HPC specialist
>
> SuperComputing Applications and Innovation Department
>
> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
>
> www.cineca.it Tel: +39 051 6171722
>
> g.fatigati [AT] cineca.it
>

-- 
Ing. Gabriele Fatigati
HPC specialist
SuperComputing Applications and Innovation Department
Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
www.cineca.it                    Tel:   +39 051 6171722
g.fatigati [AT] cineca.it