STINNER Victor <vstin...@python.org> added the comment:
PR 23976 stores the currrent interpreter and the current Python thread state into a Thread Local Storage (TLS) using GCC/clang __thread keyword. On x86-64 using LTO and GCC -O3, _PyThreadState_GET() and _PyInterpreterState_GET() become a single MOV. Assembly code using LTO and gcc -O3. _PyThreadState_GET() in _PySys_GetObjectId(): 0x00000000004adabe <+14>: mov rbx,QWORD PTR fs:0xfffffffffffffff8 _PyThreadState_GET() in PyThreadState_Get(): 0x000000000046b660 <+0>: mov rax,QWORD PTR fs:0xfffffffffffffff8 _PyInterpreterState_GET() in PyTuple_New(): 0x000000000048dfcc <+12>: mov rax,QWORD PTR fs:0xfffffffffffffff0 _PyInterpreterState_GET() in PyState_FindModule(): 0x000000000044bf20 <+16>: mov rax,QWORD PTR fs:0xfffffffffffffff0 --- Note: Without LTO, sometimes there is an indirection: _PyThreadState_GET() in _PySys_GetObjectId(), 2 MOV (PIC indirection): mov rax,QWORD PTR [rip+0x1eb270] # 0x713fe0 # rax = 0xfffffffffffffff0 (-16) mov r13,QWORD PTR fs:[rax] _PyInterpreterState_GET() in PyTuple_New(), 2 MOV (PIC indirection): mov rax,QWORD PTR [rip+0x294d95] # 0x713ff8 mov rax,QWORD PTR fs:[rax] An optimized Python should always be built with LTO. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue40522> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
