Dear Patrick, Thanks for the quick answer.
Sorry for the broken link, i send anyway the code as an tarball in my previous mail I am myself using fortran together with Lustre, using a different application IO than pure fortran i.e MPI-IO or HDF5 and it works just fine. I never used the pure fortran IO with lustre and was surprised by the low performance on our filesystem that users reported. In the tarball i adapted the pure fortran code to use a different application IO (HDF5). In this case i see no preformance problem. Could it be that i both case, there are data contention problem and/or temporal network issue but the HDF5 IO is just more resilient than fortran IO to these issue. Anyway how to check properly for these Lustre system problem ( data contention/network)? Regards, Denis ________________________________ From: Patrick Farrell <[email protected]> Sent: Thursday, February 3, 2022 4:15:16 PM To: Bertini, Denis Dr.; [email protected] Subject: Re: RE-Fortran IO problem Denis, FYI, the git link you provided seems to be non-public - it asks for a GSI login. Fortran is widely used for applications on Lustre, so it's unlikely to be a fortran specific issue. If you're seeing I/O rates drop suddenly during activity, rather than being reliably low for some particular operation, I would look to the broader Lustre system. It may be suddenly extremely busy or there could be, eg, a temporary network issue - Assuming this is a system belonging to your institution, I'd check with your admins. Regards, Patrick ________________________________ From: lustre-discuss <[email protected]> on behalf of Bertini, Denis Dr. <[email protected]> Sent: Thursday, February 3, 2022 6:43 AM To: [email protected] <[email protected]> Subject: [lustre-discuss] RE-Fortran IO problem Hi, Just as an add-on to my previous mail, the problem shows up also with intel fortran and it not specific to gnu fortran compiler. So it seems to be linked to how the fortran IO is handled which seems to be sub-optimal in cas of a Lustre filesystem. I would be grateful if one can confirm/disconfirm that. Here again the access to the code i used for my benchmarks: https://git.gsi.de/hpc/cluster/ci_ompi/-/tree/main/f/src Best, Denis --------- Denis Bertini Abteilung: CIT Ort: SB3 2.265a Tel: +49 6159 71 2240 Fax: +49 6159 71 2986 E-Mail: [email protected] GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de Commercial Register / Handelsregister: Amtsgericht Darmstadt, HRB 1528 Managing Directors / Geschäftsführung: Professor Dr. Paolo Giubellino, Dr. Ulrich Breuer, Jörg Blaurock Chairman of the GSI Supervisory Board / Vorsitzender des GSI-Aufsichtsrats: Ministerialdirigent Dr. Volkmar Dietz
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