Re: [LARTC] Low latency on large uploads - almost done but not quite.

[Thilo Schulz <arny@ats.s.bawue.de>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tuesday 17 June 2003 20:16, sufcrusher wrote:
> (one of) the reasons for the unstable ping is that a packet of ~ 1500 bytes
> on a 128kbit connection (like yours and mine) takes roughly a 10th of a
> second to send (100ms). So at the moment a large packet is being sent and a
> quake packet is next in the queue, it still has to wait 100ms (worst case).
> This latency of course adds to the normal latency you already have to the
> quake server.

Yes, I have thought so too and thought about playing around with the MTU .. 
but did not really want to change it yet.
Thank you anyways for these helpful hints, I am going to try it as soon as 
possible :)

> I'm assuming the burst and quantum settings can be optimized for smaller
> packet sizes to take full advantage of this. But to be honest I haven't
> really done that yet.

The lower the burst settings, the less delay I have in theory, so high-prio 
queues _definitely_ get their turn in time.

> I use a cable connection which has a more than 10 times faster download
> than upload, so for me shaping the download isn't very effective. If you
> want to limit the maximum packetsize for incoming packets as well (at least
> for TCP) you can simply do this:

The same applies to me, I have 768 kbyte/s downlink, I doubt that this is an 
issue when gaming.

> For 1000 bytes packets. You can also use --clamp-mss-to-mtu option, which
> probably makes sense. Note that the MSS thing only works for new
> connections.

I have to do this anyways, as my pppoe is limiting the MTU on the virtual ppp0 
device to 1492 because ethernet frames can only have a certain size and pppoe 
still encapsules ppp in the ethernet.

> Also make sure you patched the kernel to use the high resolution timer
> (info at www.docum.org somewhere). That helped a lot in my case (you can
> put the ceilingrates closer to the actual 128kbit and therefore reduce
> latency as well). I'm not sure it's still necessary on 2.4.20 and/or
> 2.4.21.

I have a 133 Mhz AMD 486 - whether setting the resolution timer up would be 
very good for performance I don't know.

 - Thilo Schulz
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.2 (GNU/Linux)

iD8DBQE+8FviZx4hBtWQhl4RAkyNAKC+3wE3bqMmQEr8qwkxdpPX6cuzdwCff03Z
6YTVuELLr1BNRPl/hym44Fw=4Qwt
-----END PGP SIGNATURE-----

_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/