Le Tue, 22 Oct 2013 10:54:03 +0200, Victor Stinner <victor.stinner@gmail.com> a écrit :
Hi,
Would it be possible to use os.pipe() on all OSes except AIX?
Pipes and socket pairs may have minor differences, but some applications may rely on these minor differences. For example, is the buffer size the same? For example, in test.support, we have two constants: PIPE_MAX_SIZE (4 MB) and SOCK_MAX_SIZE (16 MB).
For the record, pipe I/O seems a little faster than socket I/O under Linux: $ ./python -m timeit -s "import os, socket; a,b = socket.socketpair(); r=a.fileno(); w=b.fileno(); x=b'x'*1000" "os.write(w, x); os.read(r, 1000)" 1000000 loops, best of 3: 1.1 usec per loop $ ./python -m timeit -s "import os, socket; a,b = socket.socketpair(); x=b'x'*1000" "a.sendall(x); b.recv(1000)" 1000000 loops, best of 3: 1.02 usec per loop $ ./python -m timeit -s "import os; r, w = os.pipe(); x=b'x'*1000" "os.write(w, x); os.read(r, 1000)" 1000000 loops, best of 3: 0.82 usec per loop Regards Antoine.
Victor
2013/10/22 guido.van.rossum <python-checkins@python.org>:
http://hg.python.org/cpython/rev/2a0bda8d283d changeset: 86557:2a0bda8d283d user: Guido van Rossum <guido@dropbox.com> date: Mon Oct 21 20:37:14 2013 -0700 summary: Switch subprocess stdin to a socketpair, attempting to fix issue #19293 (AIX hang).
files: Lib/asyncio/unix_events.py | 29 +++++++++- Lib/test/test_asyncio/test_unix_events.py | 7 ++ 2 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py --- a/Lib/asyncio/unix_events.py +++ b/Lib/asyncio/unix_events.py if stdin == subprocess.PIPE: self._pipes[STDIN] = None + # Use a socket pair for stdin, since not all platforms + # support selecting read events on the write end of a + # socket (which we use in order to detect closing of the + # other end). Notably this is needed on AIX, and works + # just fine on other platforms. + stdin, stdin_w = self._loop._socketpair() if stdout == subprocess.PIPE: self._pipes[STDOUT] = None if stderr == subprocess.PIPE: