Subject: Re: [PATCH 1/1] net: Introduce recvmmsg socket syscall

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Mon, 12 Oct 2009 22:56:37 -0300

Em Mon, Oct 12, 2009 at 07:53:43PM +0200, Nir Tzachar escreveu:
> Hi Arnaldo.
> 
> Do you have any plans on how we can further investigate the delays I
> have seen with the second part of the patch? I have tried to simply
> unlock/lock the socket's mutex every couple of iterations inside the

Yeah, that is what tcp does, look at tcp_recvmsg (net/ipv4/tcp.c, line
1505), so I think we should do something along those lines, exactly when
and after which tests is a matter of experimentation.

I'll resume investigation tomorrow.

> loop (to allow the system to process some backlog), but this seems to
> have little to no effect.
 
> Also, a way to enable/disable the no_lock version at runtime will
> greatly help in testing. Maybe by first introducing a second syscall,
> recvmmsg_no_lock, for testing purposes??

I'll come up with a way for that to be possible.

- Arnaldo