Allow parallel I/O for hydro and particle reading #4730
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cphyc
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cphyc
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Nov 3, 2023
| @@ -1157,9 +1199,9 @@ def alltoallv_array(self, send, total_size, offsets, sizes): | |||
| dtr = send.dtype.itemsize / tmp_send.dtype.itemsize # > 1 | |||
| roff = [off * dtr for off in offsets] | |||
| rsize = [siz * dtr for siz in sizes] | |||
| tmp_recv = recv.view(self.__tocast) | |||
| tmp_recv = recv.view(transport_dtype) | |||
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The motivation for getting rid of the cast to CHAR is so that we do not hit the limit imposed by MPI of 2**31 elements when communicating arrays as quickly.
cphyc
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Nov 3, 2023
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| self.comm.send( | ||
| (arr.dtype.str, arr.shape, transport_dtype) + unit_metadata, | ||
| dest=dest, | ||
| tag=tag, | ||
| ) | ||
| self.comm.Send([arr, mpi_type], dest=dest, tag=tag) |
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Isn't there a bug here? I think this should be
Suggested change
| self.comm.send( | |
| (arr.dtype.str, arr.shape, transport_dtype) + unit_metadata, | |
| dest=dest, | |
| tag=tag, | |
| ) | |
| self.comm.Send([arr, mpi_type], dest=dest, tag=tag) | |
| self.comm.send( | |
| (arr.dtype.str, arr.shape, transport_dtype) + unit_metadata, | |
| dest=dest, | |
| tag=tag, | |
| ) | |
| self.comm.Send([tmp, mpi_type], dest=dest, tag=tag) |
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I think it should be tmp, yeah, but since it has been working I think it's possible that mpi4py was fixing it implicitly.
|
@yt-fido test this please |
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PR Summary
This allows parallel I/O for the RAMSES dataset. Reading a RAMSES dataset has three steps:
The strategy I have adopted is to parallelize on the first one, such that each MPI task is now in charge of a few domains and only reads those (incl. hydro + particles).