net: use recvmmsg on Linux

[gopherbot]

by teixeiradavid:

Hello,

Go should implement the recvmmsg linux syscall to improve peformance.
The option to use either "recvmmsg" or "recvmsg" should be available
on higher level packages like "net" when reading from a socket.

This would be a huge plus for small packet processing.

Thanks.
David.

[gopherbot]

Comment 1 by teixeiradavid:

link for the kernel commit :
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a2e2725541fad72416326798c2d7fa4dafb7d337

[rsc]

Comment 2:

Package net - a portable API - is certainly not going to grow an option just to support
the Linux system call flavor of the week.
If we do anything, it would be to make the various calls to recvmsg use recvmmsg
transparently when that's available.  However, it is unclear to me how important this
really is.  I am pretty sure this is not yet a bottleneck in real code.

Labels changed: added priority-later, removed priority-triage.

Status changed to LongTerm.

[gopherbot]

Comment 4 by teixeiradavid:

Hello, sorry for the mistake about using  an option in the net package.
This is important if you want to reduce latency on processing small packets (udp
mulicast for example), it is not a bottleneck, it's just more efficient.
Thanks.

[alexbrainman]

Comment 5:

I am pretty sure, our current windows syscalls could support these too.
Alex

[anacrolix]

Comment 6:

So is there a mac/plan9 equivalent of these? I understand Commander Rob isn't a fan of
extensions like this, can it be added say to go.net or something?

[rsc]

Comment 7:

It's fine to add these if you can't tell they're being used. API changes are not fine.

[rsc]

Comment 8:

Labels changed: added go1.3maybe.

[rsc]

Comment 9:

Labels changed: added release-none, removed go1.3maybe.

[rsc]

Comment 10:

Labels changed: added repo-main.

[ianlancetaylor]

Comment 11:

I don't see any way to use recvmmsg with the current net API (unless we add a buffer
which I think we do not want to do).

[anacrolix]

Comment 12:

It would be pretty clean to add something like func (PacketConn) MultiRecv([][]byte)
([]int, err).