[gentoo-user] Re: TCP Queuing problem

[Kai Krakow <hurikhan77@gmail.com>]

Am Wed, 21 Sep 2016 22:06:37 +0200
schrieb Kai Krakow <hurikhan77@gmail.com>:

> Am Wed, 21 Sep 2016 12:37:51 -0700
> schrieb Grant <emailgrant@gmail.com>:
> 
> >  [...]  
> >  [...]    
>  [...]  
> > >
> > > You may want to set the default congestion control to fq-codel
> > > (it's in the kernel) if you're using DSL links. This may help your
> > > problem a little bit. It is most effective if you deploy traffic
> > > shaping at the same time. There was once something like
> > > wondershaper. Trick is to get the TCP queuing back inside your
> > > router (that is where you deployed pppoe) as otherwise packets
> > > will queue up in the modem (dsl modems use huge queues by
> > > default). This works by lowering the uplink bandwith to 80-90% of
> > > measured maximum upload (the excess bandwidth is for short bursts
> > > of traffic). Traffic shaping now re-orders the packets. It should
> > > send ACK and small packets first. This should solve your queuing
> > > problem.    
> > 
> > 
> > We're talking about optimizing the DSL connection at my office but
> > the server is located in a data center.  I can't imagine optimizing
> > that office DSL connection is the way to solve this even though the
> > http response slowdowns do correlate to office hours.  As a note,
> > the slowdowns are recorded by my third-party monitoring service.  
> 
> Ah I didn't correctly get this... So as the problem correlates with
> office hours the first step of solving your traffic flow problems
> (timeouts, drops etc) should be sufficient to further work on problems
> of the other side.

I'd probably try iperf at this stage to test if this problem occurs
with application stacks only or also occurs using only raw tcp streams.
Try upload, download, and bidirectional. Do your tests again after
modifying some parameters, maybe access the http server in parallel,
test at different times of day (off-hours and office hours). See if you
can isolate it around specific settings or tasks.

-- 
Regards,
Kai

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