On Fri, Jul 26, 2013 at 3:23 PM, Antoine Pitrou <solip...@pitrou.net> wrote:
> On Sat, 27 Jul 2013 00:18:40 +0200 > Victor Stinner <victor.stin...@gmail.com> wrote: > > 2013/7/26 Antoine Pitrou <solip...@pitrou.net>: > > > On Fri, 26 Jul 2013 22:17:47 +0200 > > >> """ > > >> 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) > > >> """ > > > > > > You aren't answering my question: slower than what? > > > > Ah, you didn't understand the labels. bench_cloexec.py runs a > > benchmark on os.open(path, os.O_RDONLY, cloexec=False) and > > os.open(path, os.O_RDONLY, cloexec=True) with different implementation > > of making the file descriptor non-inheritable. > > > > close-on-flag not set: 7.8 us > > => C code: open(path, O_RDONLY) > > > > O_CLOEXEC: 1% slower (7.9 us) > > => C code: open(path, O_RDONLY|CLOEXEC) > > => 1% slower than open(path, O_RDONLY) > > > > ioctl(): 3% slower (8.0 us) > > => C code: fd=open(path, O_RDONLY); ioctl(fd, FIOCLEX, 0) > > => 3% slower than open(path, O_RDONLY) > > > > fcntl(): 3% slower (8.0 us) > > => C code: fd=open(path, O_RDONLY); flags = fcntl(fd, F_GETFD); > > fcntl(fd, F_SETFD, flags | FD_CLOEXEC) > > => 3% slower than open(path, O_RDONLY) > > Ok, so I think this it is a totally reasonable compromise. > > People who bother about a 3% slowdown when calling os.open() can > optimize the hell out of their code using Cython for all I care :-) > > +1 ;) and +1 for making the sane default of noinherit / cloexec / whatever-others-call-it by default for all fds/handles ever opened by Python. It stops ignoring the issue (ie: the status quo of matching the default behavior of C as defined in the 1970s)... That is a GOOD thing. :) -gps
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