openPMD/openPMD-api

MPI-I/O Hints

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#1,449 opened on May 23, 2023

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MPIbackend: HDF5help wanted

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Description

Recent MPI standards provide in Chapter 14 - 14.2. FILE MANIPULATION standardized options to describe file striping, e.g., on Lustre.

ROMIO seems to support this well and also OpenMPI's OMPIO works well with those in 5.0+: https://github.com/open-mpi/ompi/issues/10132

We should consider exposing these options and setting reasonable defaults :)

https://www.mpi-forum.org/docs/mpi-4.0/mpi40-report.pdf

Older keys in T3PIO for ROMIO only: https://github.com/TACC/t3pio/blob/0ea823059607bd17c0faf0dd80c5a3979bf4ba69/libt3pio/set_info.c#L160-L173

Contributor guide

Research direction
Investigate the MPI standard's file hints, specifically how ROMIO and OMPIO implement them. Explore the T3PIO reference implementation and identify the relevant parts of the openPMD api source code where MPI file info is set, to plan where hints can be exposed.
Tech stack
cpp
Domain
backendperformance
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitC++MPI
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50