Re: Serious TCP performance regression in 4.0?

[Anders Magnusson <ragge%ludd.ltu.se@localhost>]

Havard Eidnes wrote:
>>> I have recently been made aware of what appears to be a serious
>>> TCP bulk data transfer performance regression experienced by
>>> NetBSD 4.0.
>> Does setting net.inet.tcp.congctl.selected=reno (default is newreno)
>> make a difference?
> 
> Nope, it didn't.
> 
> However, I may have to retract my claim, the problem appears to
> be specific to the "iperf" program.  Re-doing some of the tests
> with good old ttcp does not show the same behaviour.
> 
> It would still be interesting to know what "iperf" does to
> trigger the problem in 4.0, but the solution to that is now not
> urgent.
> 
A side note that still might be interesting;  Mike Silbersack had a presentation
at NycBSDCon (http://www.silby.com/nycbsdcon08/NYCBSDCon-tcpdiff.pdf) about a
test program he had that compared the IP stacks on different FreeBSD releases,
to find bugs.  And he had found some bugs also :-)

Maybe NetBSD should do something similar for regression?

-- Ragge