Ok Jeff, thanks very much for your support!
Regards,
2012/1/31 Jeff Squyres
> On Jan 31, 2012, at 3:59 AM, Gabriele Fatigati wrote:
>
> > I have very interesting news. I recompiled OpenMPI 1.4.4 enabling the
> memchecker.
> >
> > Now the warning on strcmp is disappeared also without buffers
> i
On Jan 31, 2012, at 3:59 AM, Gabriele Fatigati wrote:
> I have very interesting news. I recompiled OpenMPI 1.4.4 enabling the
> memchecker.
>
> Now the warning on strcmp is disappeared also without buffers initializations
> using memset!
>
> So the warning is a false positive? My simple code
Dear Jeff,
I have very interesting news. I recompiled OpenMPI 1.4.4 enabling the
memchecker.
Now the warning on strcmp is disappeared also without buffers
initializations using memset!
So the warning is a false positive? My simple code is safe?
Thanks.
2012/1/28 Jeff Squyres
> On Jan 28, 201
On Jan 28, 2012, at 5:22 AM, Gabriele Fatigati wrote:
> I had the same idea so my simple code I have already done calloc and memset ..
>
> The same warning still appear using strncmp that should exclude uninitialized
> bytes on hostnam_recv_buf :(
Bummer.
> My apologize for being so insistent,
HI Jeff,
I had the same idea so my simple code I have already done calloc and memset
..
The same warning still appear using strncmp that should exclude
uninitialized bytes on hostnam_recv_buf :(
My apologize for being so insistent, but I would understand if there is
some bug in MPI_Allgather, st
Ah, I have an idea what might be happening here: I believe that valgrind is
actually pretty smart.
If you have a buffer of size 128, and gethostname() only fills in, say, the
first 32 bytes (including the \0), the other 128-32=96 bytes are uninitialized.
You can MPI_Allgather these, in which c
Dear Ralph, thanks for the suggest, but doesn't solve the problem :(
The warning still exists.
2012/1/27 Ralph Castain
> I suspect that valgrind doesn't recognize that MPI_Allgather will ensure
> that hostname_recv_buf is filled prior to calling strcmp. If you want to
> eliminate the warning, y
I suspect that valgrind doesn't recognize that MPI_Allgather will ensure that
hostname_recv_buf is filled prior to calling strcmp. If you want to eliminate
the warning, you should memset hostname_recv_buf to 0 so it has a guaranteed
value.
On Jan 27, 2012, at 6:21 AM, Gabriele Fatigati wrote:
Hi Jeff,
yes, very stupid bug in a code, but also with the correction the problem
with Valgrind in strcmp remains:
==21779== Conditional jump or move depends on uninitialised value(s)
==21779==at 0x4A0898C: strcmp (mc_replace_strmem.c:711)
==21779==by 0x400BA8: main (all_gather.c:28)
==21
I see one problem:
gethostname(local_hostname, sizeof(local_hostname));
That should be:
gethostname(local_hostname, max_name_len);
because sizeof(local_hostname) will be sizeof(void*).
But if that's what you were intending, just to simulate a small hostname
buffer, then be aware that
Sorry,
this is the right code.
2012/1/27 Gabriele Fatigati
> Hi Jeff,
>
> The problem is when I use strcmp on ALLGather buffer and Valgrind that
> raise a warning.
>
> Please check if the attached code is right, where size(local_hostname) is
> very small.
>
> Valgrind is used as:
>
> mpirun val
Hi Jeff,
The problem is when I use strcmp on ALLGather buffer and Valgrind that
raise a warning.
Please check if the attached code is right, where size(local_hostname) is
very small.
Valgrind is used as:
mpirun valgrind --leak-check=full --tool=memcheck ./all_gather
and openmpi/1.4.4 compiled
I'm not sure what you're asking.
The entire contents of hostname[] will be sent -- from position 0 to position
(MAX_STRING_LEN-1). If there's a \0 in there, it will be sent. If the \0
occurs after that, then it won't.
Be aware that get_hostname(buf, size) will not put a \0 in the buffer if
Dear OpenMPi users/developers,
anybody can help about such problem?
2012/1/13 Gabriele Fatigati
> Dear OpenMPI,
>
> using MPI_Allgather with MPI_CHAR type, I have a doubt about
> null-terminated character. Imaging I want to spawn node names where my
> program is running on:
>
>
> --
Dear OpenMPI,
using MPI_Allgather with MPI_CHAR type, I have a doubt about
null-terminated character. Imaging I want to spawn node names where my
program is running on:
char hostname[MAX_LEN];
char*
hostname_recv_buf=(char*)calloc(num_procs*(MAX_STRING_
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