Ryan Hileman <lunixbo...@gmail.com> added the comment:
Oops, by tb_code I meant traceback.tb_frame.f_code. So you can get to a frame from traceback.tb_frame (without triggering audit) or sys._getframe (which has an audit hook already), and you can get to __code__ from a frame via frame.f_code (without triggering audit). Here's a patch for both frame.f_code and traceback.tb_frame: https://github.com/lunixbochs/cpython/commit/2334a00c833874b7a2427e88abc9b51315bb010c --- Benchmarks follow this section, made using the commit I linked (and the parent commit without the patch for comparison). My takeaways from playing around: 1. You probably shouldn't install a Python audit hook if you care about performance. 2. C audit hook performance impact shows up in microbenchmarking but only have a small impact on real workloads (see the traceback.format_tb benchmark at the end). 3. Performance impact of this change when you _don't_ have an audit hook installed is very small. 4. This seems to mostly impact debugging and test code. A quick check of the stdlib shows: - traceback.tb_frame usage seems to be entirely in debugger, traceback, and testing code: https://github.com/python/cpython/search?l=Python&p=3&q=tb_frame - frame.f_code primarily has similar debug use (dis, warnings, profiling, inspect): https://github.com/python/cpython/search?l=Python&p=3&q=f_code Attached (c_audit_ext.zip) is the empty C audit hook I used for the benchmarks. `python3 setup.py build_ext` builds a `c_audit` module which registers an empty audit hook on import. ################################################################################ #### frame.f_code object.__getattr__ audit hook # Testing frame.f_code impact (no audit hook installed): ./python.exe -m timeit -s 'frame = sys._getframe()' -- 'frame.f_code' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 19.1 nsec per loop 20000000 loops, best of 5: 18.7 nsec per loop 20000000 loops, best of 5: 19.1 nsec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 17 nsec per loop 20000000 loops, best of 5: 16.7 nsec per loop 20000000 loops, best of 5: 17 nsec per loop # Testing frame.f_code impact (C audit hook installed): python.exe -m timeit -s 'import c_audit; frame = sys._getframe()' -- 'frame.f_code' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 5000000 loops, best of 5: 66.1 nsec per loop 5000000 loops, best of 5: 66.1 nsec per loop 5000000 loops, best of 5: 66.5 nsec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 16.9 nsec per loop 20000000 loops, best of 5: 16.9 nsec per loop 20000000 loops, best of 5: 16.8 nsec per loop # Testing frame.f_code impact (pure Python audit hook installed): ./python.exe -m timeit -s 'frame = sys._getframe(); sys.addaudithook(lambda *a: None)' -- 'frame.f_code' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 500000 loops, best of 5: 1.02 usec per loop 500000 loops, best of 5: 1.04 usec per loop 500000 loops, best of 5: 1.02 usec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 16.8 nsec per loop 20000000 loops, best of 5: 17.1 nsec per loop 20000000 loops, best of 5: 16.8 nsec per loop ################################################################################ #### tb.tb_frame object.__getattr__ audit hook # Testing tb.tb_frame impact (no audit hook installed) ./python.exe -m timeit -s "$(echo -e "try: a\nexcept Exception as e: tb = e.__traceback__")" -- 'tb.tb_frame' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 19.2 nsec per loop 20000000 loops, best of 5: 18.9 nsec per loop 20000000 loops, best of 5: 18.9 nsec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 17 nsec per loop 20000000 loops, best of 5: 16.7 nsec per loop 20000000 loops, best of 5: 16.8 nsec per loop # Testing tb.tb_frame impact (C audit hook installed) ./python.exe -m timeit -s "$(echo -e "import c_audit\ntry: a\nexcept Exception as e: tb = e.__traceback__")" -- 'tb.tb_frame' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 5000000 loops, best of 5: 64.8 nsec per loop 5000000 loops, best of 5: 64.8 nsec per loop 5000000 loops, best of 5: 64.8 nsec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 16.7 nsec per loop 20000000 loops, best of 5: 16.9 nsec per loop 20000000 loops, best of 5: 16.9 nsec per loop # Testing tb.tb_frame impact (pure Python audit hook installed) ./python.exe -m timeit -s "$(echo -e "sys.addaudithook(lambda *a: None)\ntry: a\nexcept Exception as e: tb = e.__traceback__")" -- 'tb.tb_frame' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 500000 loops, best of 5: 1.04 usec per loop 500000 loops, best of 5: 1.02 usec per loop 500000 loops, best of 5: 1.04 usec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 20000000 loops, best of 5: 16.9 nsec per loop 20000000 loops, best of 5: 16.9 nsec per loop 20000000 loops, best of 5: 17.2 nsec per loop ################################################################################ #### tb.tb_frame object.__getattr__ audit hook, traceback.format_tb() # Testing tb.tb_frame impact on traceback.format_tb (no audit hook installed) with patch 2334a00c833874b7a2427e88abc9b51315bb010c 100000 loops, best of 5: 3 usec per loop 100000 loops, best of 5: 3.03 usec per loop 100000 loops, best of 5: 3 usec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 100000 loops, best of 5: 2.99 usec per loop 100000 loops, best of 5: 3.02 usec per loop 100000 loops, best of 5: 2.99 usec per loop # Testing tb.tb_frame impact on traceback.format_tb (C audit hook installed) ./python.exe -m timeit -s "$(echo -e "import c_audit\nimport traceback\ntry: a\nexcept Exception as e: tb = e.__traceback__")" -- 'traceback.format_tb(tb)' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 100000 loops, best of 5: 3.13 usec per loop 100000 loops, best of 5: 3.13 usec per loop 100000 loops, best of 5: 3.12 usec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 100000 loops, best of 5: 3.06 usec per loop 100000 loops, best of 5: 3.06 usec per loop 100000 loops, best of 5: 3.05 usec per loop # Testing tb.tb_frame impact on traceback.format_tb (pure Python audit hook installed) ./python.exe -m timeit -s "$(echo -e "sys.addaudithook(lambda *a: None)\nimport traceback\ntry: a\nexcept Exception as e: tb = e.__traceback__")" -- 'traceback.format_tb(tb)' with patch 2334a00c833874b7a2427e88abc9b51315bb010c 50000 loops, best of 5: 5.1 usec per loop 50000 loops, best of 5: 5.18 usec per loop 50000 loops, best of 5: 5.06 usec per loop without patch 2334a00c833874b7a2427e88abc9b51315bb010c 100000 loops, best of 5: 3 usec per loop 100000 loops, best of 5: 3 usec per loop 100000 loops, best of 5: 3 usec per loop ---------- Added file: https://bugs.python.org/file49729/c_audit_ext.zip _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue42800> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
