Add support for offheap allocation in multianewarray evaluator on IBM Z platform #22797
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ehsankianifar
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Remove WIP when I finish testing |
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Local tests pass. I remove the WIP and launching jenkin tests. |
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Enhances the multianewarray evaluator to support offheap allocation on
IMB Z platform. Offheap allocation for arrays with a zero-length second
dimension is not supported; in such cases, a helper call is triggered
to handle the allocation.
Please fix typo (IBM Z not IMB Z).
I have not looked into your code - but can you confirm this statement is true or not.
- We did inline zero-length first / second dimension array when off-heap is enabled. But changes in this PR will divert those case to helper (Or only zero length second dimension) and only inlines if both dimension is not zero?
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Thanks @r30shah! I fixed the commit message. Yes, we were inlining zero length 2D arrays before, then we disable inlining offheap and with this change we enable offheap except for zero length second dim. |
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Is it that complicated to fix for zero second length that you will do in second PR? |
No I have a few ideas but want to select a plan that has minimum impact on the non zero allocation since I expect non-zero to get called more frequently. |
| dependencies->addPostCondition(dim2SizeReg, TR::RealRegister::AssignAny); | ||
| cursor = generateRXInstruction(cg, TR::InstOpCode::LTGF, node, dim2SizeReg, generateS390MemoryReference(dimsPtrReg, 0, cg), cursor); | ||
| iComment("Load 2st dim length."); | ||
| // The size of zero length array is already loaded in size register. Jump over the array size calculation instructions if length is 0. |
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Since we're no longer writing 0 to dim2SizeReg, this comment can be removed.
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Thanks shubham. Comment was removed
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@hzongaro pointed that we do not inline constant non-zero second dimension 2D arrays (#22562 (review)). I am trying to see why it was added and will remove the condition if it is not necessary anymore. |
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@ehsankianifar Is this ready for review or are you still working on adding changes? |
Thanks @VermaSh, Yes it is ready for review. |
Enhances the multianewarray evaluator to support offheap allocation on IBM Z platform. Offheap allocation for arrays with a zero-length second dimension is not supported; in such cases, a helper call is triggered to handle the allocation. signed-off-by: Ehsan Kiani Far <[email protected]>
Enhances the multianewarray evaluator to support zero-length offheap allocation on IBM Z platform. signed-off-by: Ehsan Kiani Far <[email protected]>
Previously, inlining of constant 2D arrays with a non-zero second dimension was disabled on z due to limitations in handling such cases. However, recent improvements have resolved those issues, making it safe and beneficial to inline these arrays. Remove the constraint that prevented inlining of non-zero constant second dimension 2D arrays. signed-off-by: Ehsan Kiani Far <[email protected]>
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I upload a sample compilation log with constant zero length here for reference: |
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Thank you! @ehsankianifar. Can you please share trace logs for constant and non-constant non-zero 2nd dimension? |
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Thanks @VermaSh, |
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@r30shah
This PR add support for offheap 2D array allocation. It is calling helper if the second dim is zero length and allocating offheap. I have a few possible solutions for that.