diff options
| author | Victor Stinner <vstinner@python.org> | 2020-04-24 10:06:58 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-04-24 10:06:58 (GMT) |
| commit | e6f8abd500751a834b6fff4f107ecbd29f2184fe (patch) | |
| tree | b6c864b0239aba840849bb4dba8a94d7b57b5b68 | |
| parent | 162c567d164b5742c0d1f3f8bd8c8bab9c117cd0 (diff) | |
| download | cpython-e6f8abd500751a834b6fff4f107ecbd29f2184fe.zip cpython-e6f8abd500751a834b6fff4f107ecbd29f2184fe.tar.gz cpython-e6f8abd500751a834b6fff4f107ecbd29f2184fe.tar.bz2 | |
bpo-38061: subprocess uses closefrom() on FreeBSD (GH-19697)
Optimize the subprocess module on FreeBSD using closefrom().
A single close(fd) syscall is cheap, but when sysconf(_SC_OPEN_MAX)
is high, the loop calling close(fd) on each file descriptor can take
several milliseconds.
The workaround on FreeBSD to improve performance was to load and
mount the fdescfs kernel module, but this is not enabled by default.
Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans
(kevans) and Kubilay Kocak (koobs):
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274
| -rw-r--r-- | Doc/whatsnew/3.9.rst | 4 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2020-04-24-01-55-00.bpo-38061.XmULB3.rst | 11 | ||||
| -rw-r--r-- | Modules/_posixsubprocess.c | 8 |
3 files changed, 22 insertions, 1 deletions
diff --git a/Doc/whatsnew/3.9.rst b/Doc/whatsnew/3.9.rst index ee85170..325121d 100644 --- a/Doc/whatsnew/3.9.rst +++ b/Doc/whatsnew/3.9.rst @@ -471,6 +471,10 @@ Optimizations until the main thread handles signals. (Contributed by Victor Stinner in :issue:`40010`.) +* Optimize the :mod:`subprocess` module on FreeBSD using ``closefrom()``. + (Contributed by Ed Maste, Conrad Meyer, Kyle Evans, Kubilay Kocak and Victor + Stinner in :issue:`38061`.) + Build and C API Changes ======================= diff --git a/Misc/NEWS.d/next/Library/2020-04-24-01-55-00.bpo-38061.XmULB3.rst b/Misc/NEWS.d/next/Library/2020-04-24-01-55-00.bpo-38061.XmULB3.rst new file mode 100644 index 0000000..603d80b --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-04-24-01-55-00.bpo-38061.XmULB3.rst @@ -0,0 +1,11 @@ +Optimize the :mod:`subprocess` module on FreeBSD using ``closefrom()``. +A single ``close(fd)`` syscall is cheap, but when ``sysconf(_SC_OPEN_MAX)`` is +high, the loop calling ``close(fd)`` on each file descriptor can take several +milliseconds. + +The workaround on FreeBSD to improve performance was to load and mount the +fdescfs kernel module, but this is not enabled by default. + +Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans (kevans) and +Kubilay Kocak (koobs): +https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274 diff --git a/Modules/_posixsubprocess.c b/Modules/_posixsubprocess.c index 7d5a7fe..60dd78d 100644 --- a/Modules/_posixsubprocess.c +++ b/Modules/_posixsubprocess.c @@ -264,9 +264,15 @@ _close_fds_by_brute_force(long start_fd, PyObject *py_fds_to_keep) start_fd = keep_fd + 1; } if (start_fd <= end_fd) { +#if defined(__FreeBSD__) + /* Any errors encountered while closing file descriptors are ignored */ + closefrom(start_fd); +#else for (fd_num = start_fd; fd_num < end_fd; ++fd_num) { - close(fd_num); + /* Ignore errors */ + (void)close(fd_num); } +#endif } } |