MXNET-1447 [Perl] Runtime features and large tensor support.

[sergeykolychev]

Description

[Perl] MXNET-1447 Runtime features and large tensor support.

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [MXNET-$JIRA_ID], where $JIRA_ID refers to the relevant JIRA issue created (except PRs with tiny changes)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage:
• Unit tests are added for small changes to verify correctness (e.g. adding a new operator)
• Nightly tests are added for complicated/long-running ones (e.g. changing distributed kvstore)
• Build tests will be added for build configuration changes (e.g. adding a new build option with NCCL)
• Code is well-documented:
• For user-facing API changes, API doc string has been updated.
• For new C++ functions in header files, their functionalities and arguments are documented.
• For new examples, README.md is added to explain the what the example does, the source of the dataset, expected performance on test set and reference to the original paper if applicable
• Check the API doc at https://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-$PR_ID/$BUILD_ID/index.html
• To the best of my knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

Changes

1. Added runtime features
2. Added support for large tensors

Comments

[sergeykolychev]

@tlby
Robert, could you please review. This is first from several PRs I plan to do within next few months.
It adds support for large tensors (int64) and for displaying runtime features (compile flags).

[tlby]

It seems a little awkward to put the caller in charge of checking the INT64_TENSOR_SIZE compile setting. Would it make sense to make AI::MXNetCAPI::NDArraySlice() and friends responsible for checking the flag and deferring to the NDArray*64() variants when appropriate?

[sergeykolychev]

@tlby On python side the switch is made in the caller space. The c api has two functions defined for each task, one with (u)?int32_t input/output and another with (u)?int64_t
I don't know how to combine these two functions via the swig space.
Looks like a task for you to complete later the line.

[tlby]

If that's how things are done in Python, then no need to diverge from this pattern. Thanks!

[tlby]

Is this a full switch away from the mx_ typedefs in reaction to #15899?

[sergeykolychev]

@tlby The mx_ typedefs change is a sync to current state of the mxnet/c_api.h in master branch.