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Subject: Re: [OMPI devel] SHMEM symmetric objects in shared libraries
From: Joshua Ladd (jladd.mlnx_at_[hidden])
Date: 2014-07-29 13:42:49


Gotcha, missed the shared lib part...

On Tue, Jul 29, 2014 at 1:30 PM, Pritchard Jr., Howard <howardp_at_[hidden]>
wrote:

> Hi Josh,
>
>
>
> No, I think what Bert is talking about is having something like
>
>
>
> foobar.c
> ==========================
>
> #include “shmem.h”
>
>
>
> long my_dso_val = 0;
>
>
>
> int foobar(void)
>
> {
>
> printf(“Hello from a shared library\n”);
>
> }
>
>
>
> ======
>
>
>
> cc –fPIC –c foobar.c
>
> cc –shared –o libfoobar.so foobar.o
>
> cc –o berts_code berts_code.c –lfoobar
>
>
>
> then in your main example below do a shmem_long_fadd on my_dso_val.
>
> It won’t work unless you’ve put smarts in the shmem library to go through
>
> the segments of loaded shared libraries and register them with the same
>
> mechanism used for the data segment of the executable.
>
>
>
> Howard
>
>
>
>
>
> *From:* devel [mailto:devel-bounces_at_[hidden]] *On Behalf Of *Joshua
> Ladd
> *Sent:* Tuesday, July 29, 2014 10:57 AM
> *To:* Open MPI Developers
> *Subject:* Re: [OMPI devel] SHMEM symmetric objects in shared libraries
>
>
>
> Are you claiming that in the following test, the static variable "val"
> will not be seen as a symmetric object?
>
> #include "shmem.h"
>
>
> int main( int argc, char **argv){
> long my_pe, npes, master;
>
> start_pes(0);
> my_pe = shmem_my_pe();
> npes = shmem_n_pes();
>
> master = npes - 1;
>
> /* only used on master */
> static long val = 0;
>
>
> if(my_pe != master ){
> shmem_long_fadd(&val,1,master);
> }
>
> shmem_barrier_all();
>
> return 0;
> }
>
> Josh
>
>
>
>
>
> On Tue, Jul 29, 2014 at 11:27 AM, Bert Wesarg <bert.wesarg_at_[hidden]>
> wrote:
>
> Hi,
>
> On 05/10/2014 02:46 PM, Bert Wesarg wrote:
>
> Hi,
>
> Btw, I'm pretty confident, that this Open SHMEM implementation does not
> recognize global or static variables in shared libraries as symmetric
> objects. It is probably wise to note this somewhere to the users.
>
>
> I've never got an reply to this query. Any comments on it?
>
> Bert
>
>
> Kind regards,
> Bert Wesarg
>
>
> --
> Dipl.-Inf. Bert Wesarg
> wiss. Mitarbeiter
>
> Technische Universität Dresden
> Zentrum für Informationsdienste und Hochleistungsrechnen (ZIH)
> 01062 Dresden
> Tel.: +49 (351) 463-42451
> Fax: +49 (351) 463-37773
> E-Mail: bert.wesarg_at_[hidden]
>
>
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>
>
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