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02da9437b0
swolchok reported that non-tracing usage of Tensor we are wasting a lot of time on is_symbolic() tests, e.g., when destructing SymInts. This is a regression for no good reason because we don't actually ever have SymInts in those cases. This PR moves the stored SymInts on Tensor out of line, into a separate ExtraMeta struct, which is only allocated when we make a Tensor store symbolic sizes/strides. To avoid adding another word to TensorImpl, I take over the named tensor metadata field. This makes named tensor require a double indirection and use up more space, but it's OK since we're going to delete this feature anyway soon. I restore regular int64_t storage on Tensor. This entailed reverting https://github.com/pytorch/pytorch/pull/82467 ; there are no other substantive changes to SizesAndStrides so a close review is not necessary. I don't bother optimizes sizes and strides in ExtraMeta in the same way stock tensor is optimized. I add a SymDimVector alias. I make SymInt UNCHECKED constructor public as it is a useful optimization in some situations when the int is known to be positive. I thought about storing the SymInts on the Python object instead. However, because we can allocate symbolic shape tensors directly from C++, we cannot guarantee that there is a PyInterpreter for a Tensor. So we do it this way instead; it's also faster since you don't have to take out the GIL to do accesses. Signed-off-by: Edward Z. Yang <ezyang@fb.com> Pull Request resolved: https://github.com/pytorch/pytorch/pull/84390 Approved by: https://github.com/swolchok, https://github.com/Krovatkin
17 lines
425 B
C++
17 lines
425 B
C++
#pragma once
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#include <c10/core/SymInt.h>
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#include <c10/core/impl/SizesAndStrides.h>
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#include <c10/util/SmallVector.h>
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#include <cstdint>
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namespace c10 {
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constexpr size_t kDimVectorStaticSize = C10_SIZES_AND_STRIDES_MAX_INLINE_SIZE;
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/// A container for sizes or strides
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using DimVector = SmallVector<int64_t, kDimVectorStaticSize>;
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using SymDimVector = SmallVector<c10::SymInt, kDimVectorStaticSize>;
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} // namespace c10
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