Van Jacobson's network stack restructure

John-Mark Gurney gurney_j at
Tue Jan 31 23:48:27 PST 2006

Greg 'groggy' Lehey wrote this message on Wed, Feb 01, 2006 at 11:50 +1030:
> Last week, at the in Dunedin, Van Jacobson presented
> some slides about work he has been doing rearchitecting the Linux
> network stack.  He claims to have reduced the CPU usage by 80% and
> doubled network throughput (he expects more, but it was limited by
> memory bandwidth).  The approach looks like it would work on FreeBSD
> as well.  I spoke to him and he confirmed.
> He's currently trying to get the code released as open source, but in
> the meantime his slides are up on
>  Yes, this is my web
> site.  The conference organizers are going to put it up on their web
> site soon, but in the meantime he's asked me to put it were I can.
> Comments?

I must say that the idea of requiring the userland to provide receive
buffers before you can open up a window is a cool idea...  This means
that instead of the normal failure mode of a box that can't handle all
the data it's receiving because of lack of cpu processing, the kernel
buffers won't fill up..  only the allocated userland buffers will..

This also has interesting possibilities for smarter ethernet cards
where the card can dump it directly into the userland buffer w/o having
to do the special page flipping thing we can do now...

definately some interesting ideas...

  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."

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