8000 gh-121313: multiprocessing: change connection buffer size to 64KiB by methane · Pull Request #123559 · python/cpython · GitHub
[go: up one dir, main page]

Skip to content

gh-121313: multiprocessing: change connection buffer size to 64KiB #123559

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 9 commits into from
Sep 3, 2024
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 4 additions & 16 deletions Lib/multiprocessing/connection.py
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,6 @@
import io
import itertools
import os
import stat
import sys
import socket
import struct
Expand All @@ -40,7 +39,9 @@
#
#

BUFSIZE = 8192
# 64 KiB is the default PIPE buffer size of most POSIX platforms.
BUFSIZE = 64 * 1024

# A very generous timeout when it comes to local connections...
CONNECTION_TIMEOUT = 20.

Expand Down Expand Up @@ -361,11 +362,6 @@ def _get_more_data(self, ov, maxsize):
f.write(ov.getbuffer())
return f

"""
The default size of a pipe on Linux systems is 16 times the base page size:
https://man7.org/linux/man-pages/man7/pipe.7.html
"""
PAGES_PER_PIPE = 16

class Connection(_ConnectionBase):
"""
Expand All @@ -378,14 +374,11 @@ def _close(self, _close=_multiprocessing.closesocket):
_close(self._handle)
_write = _multiprocessing.send
_read = _multiprocessing.recv
_default_pipe_size = 0
else:
def _close(self, _close=os.close):
_close(self._handle)
_write = os.write
_read = os.read
_base_page_size = os.sysconf(os.sysconf_names['SC_PAGESIZE'])
_default_pipe_size = _base_page_size * PAGES_PER_PIPE

def _send(self, buf, write=_write):
remaining = len(buf)
Expand All @@ -400,13 +393,8 @@ def _recv(self, size, read=_read):
buf = io.BytesIO()
handle = self._handle
remaining = size
is_pipe = False
if size > self._default_pipe_size > 0:
mode = os.fstat(handle).st_mode
is_pipe = stat.S_ISFIFO(mode)
limit = self._default_pipe_size if is_pipe else remaining
while remaining > 0:
to_read = min(limit, remaining)
to_read = min(BUFSIZE, remaining)
chunk = read(handle, to_read)
n = len(chunk)
if n == 0:
Expand Down

This file was deleted.

Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Limit the reading size in the :class:`multiprocessing.connection.Connection` class to 64 KiB to prevent memory overallocation and unnecessary memory management system calls.
Loading
0