[lug] Slow runnings on KRUD7 w/ 2.4.2 and KRUD7 router.

D. Stimits stimits at idcomm.com
Mon Mar 12 18:13:22 MST 2001

John Starkey wrote:
> I'm running two KRUD7 boxes. 1 is just routing and filtering and is a
> stock kernel and the second is a gnome desktop running 2.4. I am also
> viewing my work on an iMac which is routed by the first box. The iMac is
> running usual speed consistently using all the normal net protocols.
> But the gnome box has some very serious lag at times with all the
> protocols. I'm in vi on a remote server and it's getting really
> annoying. Like taking up to a minute per space when it moves, at times,
> then 20 minutes later it will fly. The only thing I can reproduce so far
> is when I restart it will come up fine.... then ten minutes later I'm
> dead in the water again.
> Memory is at approx 40 percent and CPU is fine. I guess the router isn't
> to blame since the iMac is fine. Windoze on this dual boot was fine last
> night, while the gnome boot was lagging just before. This has been going
> on for two days and i don't think I made any major changes, in fact i'm
> pretty sure, same kernel, NIC (via-rhine), everything.
> Anyone know what else i could look at to track this down?
> Thanks,
> john

One minor suggestion, that probably won't be of great help. If the MTU's
are too high on both machines, it might not be too responsive. If you
run "ifconfig", you will see a reference to MTU, which defaults to 1500.
This is good for internal nets and more reliable connections like T1's,
but can really suck on a modem. For modems I tend to take a power of 2
and add 40 to it (size of TCP headers) and get best luck with either 256
+ 40 or 512 + 40. If you do anything requiring responsiveness, you are
probably best with 296 (256 + 40). In the case of ppp, this is done
through an option to the pppd daemon. You can also do this with MRU, but
MRU is only a suggestion, and can be ignored, so it tends to be less
useful. For example, your /etc/ppp/options might have in it:
mtu 296
mru 556

D. Stimits, stimits at idcomm.com

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