[io] Deprecate TMPIFile and the mpi build option#22846
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TMPIFile and its `mpi` build option are deprecated and scheduled for removal in the next release cycle. TMPIFile originated in the US DOE HEP-CCE program as a demonstrator for in-flight merging of ROOT output from MPI ranks in ATLAS event processing on DOE supercomputers (Theta at ALCF, Cori at NERSC): worker ranks send TMemFile buffers over MPI to collector ranks that merge them into a single output file (taken from this repo [1]). It was developed at ANL/LBNL from 2018 on, upstreamed in PR root-project#4375 (December 2019), and presented at CHEP 2019 [2]. Development stopped weeks after the merge: the last functional commit to `io/mpi` dates from January 2020, the original hep-cce/TMPIFile repository is frozen, the workflow was never adopted in production, and the HPC systems the demonstrator targeted have since been decommissioned. Every io/mpi commit since 2020 has been a mechanical tree-wide cleanup. The package is disabled by default and has no owner in the ROOT team. Deprecating the package also frees up the too-generically named `mpi` CMake option, which gates only TMPIFile, its tutorial, and its roottest test. MPI support in Minuit2 is unaffected: it is controlled by the independent `minuit2_mpi` option, which finds MPI on its own. [1] https://github.com/hep-cce/TMPIFile [2] https://indico.cern.ch/event/773049/contributions/3473315/, proceedings: https://zenodo.org/records/3599673
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Test Results 23 files 23 suites 3d 17h 37m 42s ⏱️ Results for commit 68a8cc4. |
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TMPIFile and its
mpibuild option are deprecated and scheduled for removal in the next release cycle.TMPIFile originated in the US DOE HEP-CCE program as a demonstrator for in-flight merging of ROOT output from MPI ranks in ATLAS event processing on DOE supercomputers (Theta at ALCF, Cori at NERSC): worker ranks send TMemFile buffers over MPI to collector ranks that merge them into a single output file (taken from this repo [1]). It was developed at ANL/LBNL from 2018 on, upstreamed in PR #4375 (December 2019), and presented at CHEP 2019 [2].
Development stopped weeks after the merge: the last functional commit to
io/mpidates from January 2020, the original hep-cce/TMPIFile repository is frozen, the workflow was never adopted in production, and the HPC systems the demonstrator targeted have since been decommissioned. Every io/mpi commit since 2020 has been a mechanical tree-wide cleanup. The package is disabled by default and has no owner in the ROOT team.Deprecating the package also frees up the too-generically named
mpiCMake option, which gates only TMPIFile, its tutorial, and its roottest test. MPI support in Minuit2 is unaffected: it is controlled by the independentminuit2_mpioption, which finds MPI on its own.[1] https://github.com/hep-cce/TMPIFile
[2] https://indico.cern.ch/event/773049/contributions/3473315/,
proceedings: https://zenodo.org/records/3599673