2013/7/26 Antoine Pitrou <solip...@pitrou.net>: >> The main drawback is the additionnal syscalls: on some platforms, 2 >> additional syscalls are need to make a file descriptor non-inheritable >> for each creation of file descriptor. According to my benchmark on the >> implementation of the PEP 433: the overhead of making a file >> descriptor non-inheritable is between 1% and 3% (7.8 µs => 7.9 or 8.0 >> µs) on Linux 3.6. > > 1% and 3% of what? > You're telling us there's a 0.1µs overhead. It's positively tiny.
Copy-paste of the link: """ On Linux, setting the close-on-flag has a low overhead on performances. Results of bench_cloexec.py on Linux 3.6: - close-on-flag not set: 7.8 us - O_CLOEXEC: 1% slower (7.9 us) - ioctl(): 3% slower (8.0 us) - fcntl(): 3% slower (8.0 us) """ The overhead is between 0.1 and 0.2 µs (100 and 200 ns) according to my micro-benchmark. "python -c pass" takes 19,000 µs (0.019 sec) on my PC. It uses 207 syscalls creating file descriptors (open() and openat()): 67 are successful, 140 are failing with ENOENT. The estimated overhead on "python -c pass" is 0.2*67=13.4 µs (0.07%). Victor _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
