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From: Thomas Koenig
Sent: Saturday, February 26, 2022 10:20:25 AM
To: Bertini, Denis Dr.; Harald Anlauf
Cc: Tobias Burnus; fortran@gcc.gnu.org
Subject: Re: Problem setting buffer size for gfortran ( v 11.2)
On 25.02.22 21:53, Bertini, Denis Dr. via Fortran wrote:
>
Hi Harald,
Yes i tried other values.
It seems that the value set in the foreseen environment variable is just
ignored.
And always a buffer size of 8kiB is used, which is the default values
for formatted I/O harcoded in libgfortran.
The only way to change this value is editing and recompiling
port GFORTRAN_FORMATTED_BUFFER_SIZE=1
export GFORTRAN_UNFORMATTED_BUFFER_SIZE=1
export GFORTRAN_UNBUFFERED_ALL=n
Does not work even on gcc/gfortran 11.2
If i set the same way some environment variables for openMPI,
it is working.
So this is not related to the forwarding of environment
09:15, Bertini, Denis Dr. via Fortran wrote:
> I can try that but on our cluster we are bound to use
>srun (slurm).
> Do you know how to use the same functionality with srun
> to set the environment variables.
I didn't – but the manual did: srun --export=...
See: https
, Denis Dr.; Harald Anlauf
Cc: fortran@gcc.gnu.org
Subject: Re: Problem setting buffer size for gfortran ( v 11.2)
Hi,
On 24.02.22 08:57, Bertini, Denis Dr. via Fortran wrote:
> Additonnaly i ran interactively my test program without slurm on with just
> one MPI process on
I think you eith
Hi Harald,
Good point.
I export both environment variables
export GFORTRAN_UNFORMATTED_BUFFER_SIZE=1024000
export GFORTRAN_UNBUFFERED_ALL=n
directly in the script wich is used within the sbatch main submit script.
I added ( in case ) the export also in my .bashrc profile.
So i guess all ra
Hi Harald,
I ran also the same with gfortran v11.2. together with singularity and
did not work as well.
Then i change the defintion of the buffer size in unix.c to default at 1 MiB
and it works.
What do you mean by vendor?
Do you think the problem could be linked to running fortran within sin
rg
Subject: Re: Problem setting buffer size for gfortran ( v 11.2)
Hi Denis,
Am 23.02.22 um 17:10 schrieb Bertini, Denis Dr. via Fortran:
> Hi
> Investigating some sporadical performance drop when using Fortran IO on our
> Lustre
> shared file system, we realized that the buffer size
Hi
Investigating some sporadical performance drop when using Fortran IO on our
Lustre
shared file system, we realized that the buffer size used as default by the gnu
fortran
compiler is 8 kiB only.
We wanted to change this default and according to the documentation, one has
just to set
the envir
