37 lines
1.3 KiB
ReStructuredText
37 lines
1.3 KiB
ReStructuredText
.. _libc_gpu_testing:
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============================
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Testing the GPU libc library
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============================
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.. note::
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Running GPU tests with high parallelism is likely to cause spurious failures,
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out of resource errors, or indefinite hangs. limiting the number of threads
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used while testing using ``LIBC_GPU_TEST_JOBS=<N>`` is highly recommended.
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.. contents:: Table of Contents
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:depth: 4
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:local:
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Testing Infrastructure
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======================
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The testing support in LLVM's libc implementation for GPUs is designed to mimic
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the standard unit tests as much as possible. We use the :ref:`libc_gpu_rpc`
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support to provide the necessary utilities like printing from the GPU. Execution
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is performed by emitting a ``_start`` kernel from the GPU
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that is then called by an external loader utility. This is an example of how
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this can be done manually:
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.. code-block:: sh
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$> clang++ crt1.o test.cpp --target=amdgcn-amd-amdhsa -mcpu=gfx90a -flto
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$> ./amdhsa_loader --threads 1 --blocks 1 a.out
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Test Passed!
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Unlike the exported ``libcgpu.a``, the testing architecture can only support a
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single architecture at a time. This is either detected automatically, or set
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manually by the user using ``LIBC_GPU_TEST_ARCHITECTURE``. The latter is useful
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in cases where the user does not build LLVM's libc on machine with the GPU to
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use for testing.
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