HEADS UP: inpcb/inpcbinfo rwlocking: coming to a 7-STABLE
branch near you
alfred at freebsd.org
Sun Aug 10 01:42:11 UTC 2008
Robert, reviews of sorecv_drgram:
/* XXXRW: sbwait() may not be as happy without sblock(). */
error = sbwait(&so->so_rcv);
Does not need XXX, sbwait waits for data, it's not really related
to sblock(). remove comment.
The variable orig_resid can be removed, I think the purpose
of it is to to restart blocking in the "generic sorecv" case,
in your code you only set it, you never reference it.
* Robert Watson <rwatson at FreeBSD.org> [080806 23:37] wrote:
> On Wed, 6 Aug 2008, Alfred Perlstein wrote:
> >* David G Lawrence <dg at dglawrence.com> [080805 11:37] wrote:
> >>>The thrust of this change is to replace the mutexes protecting the inpcb
> >>>and inpcbinfo data structures with read-write locks (rwlocks). These
> >> That's really cool and directly affects my current work project. I'm
> >>developing (have developed, actually) a multi-threaded, 5000+ member
> >>VoIP/SIP conferencing server called Nconnect. It a primarily UDP
> >>application running on FreeBSD 7. This generates and receives about
> >>250,000 UDP packets a second, with 200 byte packets, resulting in about
> >>400Mbps of traffic in each direction. The current bottleneck is the
> >>kernel UDP processing. It should be possible to scale to 10000+ members
> >>if kernel UDP processing had optimal concurrency.
> >> Anyway, thumbs up (and not for the middle-eastern meaning :-)) - I'm
> >>looking forward to the MFC.
> >David, one thing I noticed was that it appears that UDP sockets are
> >serialized for copyout.
> >Mainly that the socket is sblock()'d while the uiomove happens.
> >I was trying to figure out a way to bypass this somehow. Perhaps just
> >dequeuing and unlocking, the copyout after dropping the sblock.
> >If there's some error, then requeue or discard the packet.
> >I'll have to think about it.
> Or you can use the soreceive_dgram implementation in 8.x, which I will at
> some point MFC once I'm comfortable it doesn't contain any serious bugs.
> Robert N M Watson
> Computer Laboratory
> University of Cambridge
- Alfred Perlstein
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