gh-115999: Add free-threaded specialization for STORE_SUBSCR
#127169
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The specialization only depends on the type, so no special thread-safety considerations there. STORE_SUBSCR_LIST_INT needs to lock the list before modifying it. `_PyDict_SetItem_Take2` already internally locks the dictionary using a critical section.
Python/ceval_macros.h
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| // avoid any potentially escaping calls (like PyStackRef_CLOSE) while the | ||
| // object is locked. | ||
| #ifdef Py_GIL_DISABLED | ||
| # define LOCK_OBJECT(op) PyMutex_LockFast(&(_PyObject_CAST(op))->ob_mutex) |
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@mpage, I think this locking pattern will be slightly faster than using critical sections inline in bytecodes.c. The downside is that we will deopt if there's any lock contention, but I think that's an okay tradeoff.
If we decide to go with this pattern, we can update UNPACK_SEQUENCE_LIST to use it.
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@corona10 - I put my name down next to |
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Python/ceval_macros.h
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| // avoid any potentially escaping calls (like PyStackRef_CLOSE) while the | ||
| // object is locked. | ||
| #ifdef Py_GIL_DISABLED | ||
| # define LOCK_OBJECT(op) PyMutex_LockFast(&(_PyObject_CAST(op))->ob_mutex) |
Race condition with the wrong lock :) Fine, thank you for the work, I've updated the list of issues. |
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Please add test codes at test_opcache.py
cpython/Lib/test/test_opcache.py
Line 1227 in d24a22e
Co-authored-by: Donghee Na <donghee.na92@gmail.com>
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Performance difference is marginal: 1.00x faster (but 99.99% likely to be faster) I think it's worth doing even if the perf is neutral just to minimize divergence with the default (GIL) build. |
pythongh-127518: Fix pystats build after python#127619
…ython#127169) The specialization only depends on the type, so no special thread-safety considerations there. STORE_SUBSCR_LIST_INT needs to lock the list before modifying it. `_PyDict_SetItem_Take2` already internally locks the dictionary using a critical section.
pythongh-127518: Fix pystats build after python#127619
The specialization only depends on the type, so no special thread-safety considerations there.
STORE_SUBSCR_LIST_INT needs to lock the list before modifying it.
_PyDict_SetItem_Take2already internally locks the dictionary using a critical section.--disable-gilbuilds #115999