Network stack cloning / virtualization patches
Sean Chittenden
sean at chittenden.org
Mon Jun 2 13:02:01 PDT 2003
> > Has anyone looked at making the patch work with CURRENT? Does
> > this do anything to degrade performance of UP systems with no (0?)
> > virtualised images running?
>
> I have been running tests between two machines with this patch
> installed. There is a "per packet" overhead increase of about 1%.
> there is no overhead increase in the per-byte overhead.. in ther
> words, sending 1 byte packets gets about a 1% decrease in throughput
> but sending 8k chunks has almost no overhead increase..
>
> Both my machines end up maxing out the 100Mb ethernet between them
> before they see any speed difference at high packet sizes.
1% per packet seems a bit high... where is the overhead coming from?
Seems as though there should be less overhead and that lookup of the
necessary components for each vimage could be found with a hash... I
looked through the patch and couldn't see any places that screamed
optimization. Is the overhead really just from copying the data of
the vimage around?
> > Does it make the locking situation much worse? Can it be stripped
> > down to minimal, clean, well-architected diffs to accomplish a
> > centralised goal, rather than a "Network+goodies, random subsystem
> > overhaul"?
>
> It is unlikely that the patches could be made in smaller orthogonal
> patches. Its kind of "all or nothing".. Either everything is global
> or it is in a structure (per VM).
*nods* Hrm, it would appear so.
> > If this is your priority patch, hunting down someone with serious
> > network\ stack-fu to review the diff, and whatnot, would probably
> > be a good investment of your time in that regard.
>
> I'll bepresenting Marco's paper at USENIX on the (ummm 12th I
> think). His baby is due then so he can't make it.. (whereas mine
> arrived today so I'll be looking for an excuse to be away from the
> house for 2 days ;-)
:) Congrats (again!)!
Julian, am I safe in assuming that you have an interest in this work?
If not, I may setup a p4 branch to work with and to merge these bits
into -CURRENT if no one else is interested. -sc
--
Sean Chittenden
More information about the freebsd-hackers
mailing list