forked from python/cpython
-
Notifications
You must be signed in to change notification settings - Fork 2
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge remote-tracking branch 'upstream/main' into pythongh-109595
- Loading branch information
Showing
201 changed files
with
5,735 additions
and
1,837 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.
Oops, something went wrong.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
|
@@ -33,4 +33,5 @@ Currently, the HOWTOs are: | |
perf_profiling.rst | ||
annotations.rst | ||
isolating-extensions.rst | ||
timerfd.rst | ||
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,230 @@ | ||
.. _timerfd-howto: | ||
|
||
***************************** | ||
timer file descriptor HOWTO | ||
***************************** | ||
|
||
:Release: 1.13 | ||
|
||
This HOWTO discusses Python's support for the linux timer file descriptor. | ||
|
||
|
||
Examples | ||
======== | ||
|
||
The following example shows how to use a timer file descriptor | ||
to execute a function twice a second: | ||
|
||
.. code-block:: python | ||
# Practical scripts should use really use a non-blocking timer, | ||
# we use a blocking timer here for simplicity. | ||
import os, time | ||
# Create the timer file descriptor | ||
fd = os.timerfd_create(time.CLOCK_REALTIME) | ||
# Start the timer in 1 second, with an interval of half a second | ||
os.timerfd_settime(fd, initial=1, interval=0.5) | ||
try: | ||
# Process timer events four times. | ||
for _ in range(4): | ||
# read() will block until the timer expires | ||
_ = os.read(fd, 8) | ||
print("Timer expired") | ||
finally: | ||
# Remember to close the timer file descriptor! | ||
os.close(fd) | ||
To avoid the precision loss caused by the :class:`float` type, | ||
timer file descriptors allow specifying initial expiration and interval | ||
in integer nanoseconds with ``_ns`` variants of the functions. | ||
|
||
This example shows how :func:`~select.epoll` can be used with timer file | ||
descriptors to wait until the file descriptor is ready for reading: | ||
|
||
.. code-block:: python | ||
import os, time, select, socket, sys | ||
# Create an epoll object | ||
ep = select.epoll() | ||
# In this example, use loopback address to send "stop" command to the server. | ||
# | ||
# $ telnet 127.0.0.1 1234 | ||
# Trying 127.0.0.1... | ||
# Connected to 127.0.0.1. | ||
# Escape character is '^]'. | ||
# stop | ||
# Connection closed by foreign host. | ||
# | ||
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | ||
sock.bind(("127.0.0.1", 1234)) | ||
sock.setblocking(False) | ||
sock.listen(1) | ||
ep.register(sock, select.EPOLLIN) | ||
# Create timer file descriptors in non-blocking mode. | ||
num = 3 | ||
fds = [] | ||
for _ in range(num): | ||
fd = os.timerfd_create(time.CLOCK_REALTIME, flags=os.TFD_NONBLOCK) | ||
fds.append(fd) | ||
# Register the timer file descriptor for read events | ||
ep.register(fd, select.EPOLLIN) | ||
# Start the timer with os.timerfd_settime_ns() in nanoseconds. | ||
# Timer 1 fires every 0.25 seconds; timer 2 every 0.5 seconds; etc | ||
for i, fd in enumerate(fds, start=1): | ||
one_sec_in_nsec = 10**9 | ||
i = i * one_sec_in_nsec | ||
os.timerfd_settime_ns(fd, initial=i//4, interval=i//4) | ||
timeout = 3 | ||
try: | ||
conn = None | ||
is_active = True | ||
while is_active: | ||
# Wait for the timer to expire for 3 seconds. | ||
# epoll.poll() returns a list of (fd, event) pairs. | ||
# fd is a file descriptor. | ||
# sock and conn[=returned value of socket.accept()] are socket objects, not file descriptors. | ||
# So use sock.fileno() and conn.fileno() to get the file descriptors. | ||
events = ep.poll(timeout) | ||
# If more than one timer file descriptors are ready for reading at once, | ||
# epoll.poll() returns a list of (fd, event) pairs. | ||
# | ||
# In this example settings, | ||
# 1st timer fires every 0.25 seconds in 0.25 seconds. (0.25, 0.5, 0.75, 1.0, ...) | ||
# 2nd timer every 0.5 seconds in 0.5 seconds. (0.5, 1.0, 1.5, 2.0, ...) | ||
# 3rd timer every 0.75 seconds in 0.75 seconds. (0.75, 1.5, 2.25, 3.0, ...) | ||
# | ||
# In 0.25 seconds, only 1st timer fires. | ||
# In 0.5 seconds, 1st timer and 2nd timer fires at once. | ||
# In 0.75 seconds, 1st timer and 3rd timer fires at once. | ||
# In 1.5 seconds, 1st timer, 2nd timer and 3rd timer fires at once. | ||
# | ||
# If a timer file descriptor is signaled more than once since | ||
# the last os.read() call, os.read() returns the nubmer of signaled | ||
# as host order of class bytes. | ||
print(f"Signaled events={events}") | ||
for fd, event in events: | ||
if event & select.EPOLLIN: | ||
if fd == sock.fileno(): | ||
# Check if there is a connection request. | ||
print(f"Accepting connection {fd}") | ||
conn, addr = sock.accept() | ||
conn.setblocking(False) | ||
print(f"Accepted connection {conn} from {addr}") | ||
ep.register(conn, select.EPOLLIN) | ||
elif conn and fd == conn.fileno(): | ||
# Check if there is data to read. | ||
print(f"Reading data {fd}") | ||
data = conn.recv(1024) | ||
if data: | ||
# You should catch UnicodeDecodeError exception for safety. | ||
cmd = data.decode() | ||
if cmd.startswith("stop"): | ||
print(f"Stopping server") | ||
is_active = False | ||
else: | ||
print(f"Unknown command: {cmd}") | ||
else: | ||
# No more data, close connection | ||
print(f"Closing connection {fd}") | ||
ep.unregister(conn) | ||
conn.close() | ||
conn = None | ||
elif fd in fds: | ||
print(f"Reading timer {fd}") | ||
count = int.from_bytes(os.read(fd, 8), byteorder=sys.byteorder) | ||
print(f"Timer {fds.index(fd) + 1} expired {count} times") | ||
else: | ||
print(f"Unknown file descriptor {fd}") | ||
finally: | ||
for fd in fds: | ||
ep.unregister(fd) | ||
os.close(fd) | ||
ep.close() | ||
This example shows how :func:`~select.select` can be used with timer file | ||
descriptors to wait until the file descriptor is ready for reading: | ||
|
||
.. code-block:: python | ||
import os, time, select, socket, sys | ||
# In this example, use loopback address to send "stop" command to the server. | ||
# | ||
# $ telnet 127.0.0.1 1234 | ||
# Trying 127.0.0.1... | ||
# Connected to 127.0.0.1. | ||
# Escape character is '^]'. | ||
# stop | ||
# Connection closed by foreign host. | ||
# | ||
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) | ||
sock.bind(("127.0.0.1", 1234)) | ||
sock.setblocking(False) | ||
sock.listen(1) | ||
# Create timer file descriptors in non-blocking mode. | ||
num = 3 | ||
fds = [os.timerfd_create(time.CLOCK_REALTIME, flags=os.TFD_NONBLOCK) | ||
for _ in range(num)] | ||
select_fds = fds + [sock] | ||
# Start the timers with os.timerfd_settime() in seconds. | ||
# Timer 1 fires every 0.25 seconds; timer 2 every 0.5 seconds; etc | ||
for i, fd in enumerate(fds, start=1): | ||
os.timerfd_settime(fd, initial=i/4, interval=i/4) | ||
timeout = 3 | ||
try: | ||
conn = None | ||
is_active = True | ||
while is_active: | ||
# Wait for the timer to expire for 3 seconds. | ||
# select.select() returns a list of file descriptors or objects. | ||
rfd, wfd, xfd = select.select(select_fds, select_fds, select_fds, timeout) | ||
for fd in rfd: | ||
if fd == sock: | ||
# Check if there is a connection request. | ||
print(f"Accepting connection {fd}") | ||
conn, addr = sock.accept() | ||
conn.setblocking(False) | ||
print(f"Accepted connection {conn} from {addr}") | ||
select_fds.append(conn) | ||
elif conn and fd == conn: | ||
# Check if there is data to read. | ||
print(f"Reading data {fd}") | ||
data = conn.recv(1024) | ||
if data: | ||
# You should catch UnicodeDecodeError exception for safety. | ||
cmd = data.decode() | ||
if cmd.startswith("stop"): | ||
print(f"Stopping server") | ||
is_active = False | ||
else: | ||
print(f"Unknown command: {cmd}") | ||
else: | ||
# No more data, close connection | ||
print(f"Closing connection {fd}") | ||
select_fds.remove(conn) | ||
conn.close() | ||
conn = None | ||
elif fd in fds: | ||
print(f"Reading timer {fd}") | ||
count = int.from_bytes(os.read(fd, 8), byteorder=sys.byteorder) | ||
print(f"Timer {fds.index(fd) + 1} expired {count} times") | ||
else: | ||
print(f"Unknown file descriptor {fd}") | ||
finally: | ||
for fd in fds: | ||
os.close(fd) | ||
sock.close() | ||
sock = None | ||
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.