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gh-100146: Steal references from stack when building a list#100147
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d223e29 to808385cCompareWhen executing the BUILD_LIST opcode, steal the references from the stack,in a manner similar to the BUILD_TUPLE opcode. Implement this by offloadingthe logic to a new private API, _PyList_FromArraySteal(), that works similarlyto _PyTuple_FromArraySteal().This way, instead of performing multiple stack pointer adjustments while thelist is being initialized, the stack is adjusted only once and a fast memorycopy operation is performed in one fell swoop.
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Yeah, looks good to me. We probably won't be able to prove this improves performance, but I don't doubt that plenty of code will benefit from such a micro-optimization.
Ping me Monday about merging it.
bedevere-bot commentedDec 10, 2022
🤖 New build scheduled with the buildbot fleet by@gvanrossum for commit9379cd4 🤖 If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again. |
I've requested a buildbot build to make sure there isn't some dumb issue with refleaks. |
| Improve ``BUILD_LIST`` opcode so that it works similarly to the | ||
| ``BUILD_TUPLE`` opcode, by stealing references from the stack rather than | ||
| repeatedly using stack operations to set list elements. Implementation | ||
| details are in a new private API :c:func:`_PyList_FromArraySteal`. |
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| details are in a new private API:c:func:`_PyList_FromArraySteal`. | |
| details are in a new private API:c:func:`!_PyList_FromArraySteal`. |
No need to link to private functions.
| Improve ``BUILD_LIST`` opcode so that it works similarly to the | ||
| ``BUILD_TUPLE`` opcode, by stealing references from the stack rather than |
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| Improve``BUILD_LIST`` opcodeso that it works similarly tothe | |
| ``BUILD_TUPLE`` opcode, by stealing references from the stack rather than | |
| Improve:opcode:`BUILD_LIST`so that it works similarly to | |
| :opcode:`BUILD_TUPLE`, by stealing references from the stack rather than |
I don't know what's up with the ARM64 Windows buildbot, but it's been failing the same way for at least three days, so no need to worry that this PR could somehow have made it go red. |
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Thanks, this looks solid. |
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When executing the BUILD_LIST opcode, steal the references from the stack, in a manner similar to the BUILD_TUPLE opcode. Implement this by offloading the logic to a new private API, _PyList_FromArraySteal(), that works similarly to _PyTuple_FromArraySteal().
This way, instead of performing multiple stack pointer adjustments while the list is being initialized, the stack is adjusted only once and a fast memory copy operation is performed in one fell swoop.