Feature #11145
closed[PATCH] socket: avoid redundant fcntl with MSG_DONTWAIT
Description
MSG_DONTWAIT is enough to force non-blocking I/O under Linux,
so avoid changing the state of a socket. This will allow certain
threads to do a non-destructive non-blocking "peek" while others
block (without relying on an extra ppoll syscall).
I suspect any OS with the MSG_DONTWAIT flag implements it correctly. AFAIK,
MSG_DONTWAIT is only on FreeBSD and Linux, and I've only tested on Linux.
- ext/socket/init.c (rsock_s_recvfrom_nonblock): avoid redundant fcntl
Files
Updated by normalperson (Eric Wong) over 9 years ago
- File 0001-socket-avoid-redundant-fcntl-on-Linux.patch 0001-socket-avoid-redundant-fcntl-on-Linux.patch added
Better patch to support sending, too. I'm limiting this to Linux-only since
it seems newer FreeBSD has support for MSG_DONTWAIT, but I'm not sure it is
complete.
I'll commit in a few days
Updated by Anonymous over 9 years ago
- Status changed from Open to Closed
Applied in changeset r50666.
socket: avoid redundant fcntl on Linux
- ext/socket/ancdata.c (bsock_sendmsg_internal,
bsock_recvmsg_internal):
avoid redundant fcntl on Linux
[ruby-core:69154] [Feature #11145] - ext/socket/init.c (rsock_s_recvfrom_nonblock): ditto
- ext/socket/rubysocket.h (MSG_DONTWAIT_RELIABLE): new macro
MSG_DONTWAIT is enough to force non-blocking I/O under Linux,
so avoid changing the state of a socket. This will allow certain
threads to do a non-destructive non-blocking "peek" while others
block (without relying on an extra ppoll syscall).
We shall be conservative about enabling this feature since some
OSes may have incomplete support for MSG_DONTWAIT. I shall
defer to a FreeBSD expert to enable that for FreeBSD.