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
This commit is contained in:
parent
162c567d16
commit
e6f8abd500
|
@ -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
|
||||
=======================
|
||||
|
|
|
@ -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
|
|
@ -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
|
||||
}
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in New Issue