About Network performance

[Mr. Worm~~]

I've been using ULE for a long time, and it's a great program and I see frequent updates and noticed that network throughput is working at 1/10 of its potential since from hadrware perspective 100mbps/full duplex is detected and works as it is 10mbps/half duplex, regarding CSMA/CD control (full/half duplex), I suspect that the problem relies on drivers used for the PS2NIC and maybe deserves some investigation in order to improve network throughtput 10 times...so a std 700megs movie will take 2 minutes instead of 20...
No hurry, just a thing to take in consideration for some day...
Maybe I've mentioned this sometime ago, or someone else did...cya ;)

[adavidm]

Intresting,

Have you actually seen collisions occuring on the connection, or does it just "feel" like a 10Mbps/half duplex connection? I thought the slow speeds were due to the way the IOP has to poll the NIC, rather than using DMA.

I have a fluke network tester at work that I could borrow to do some checking for collisions and other bad frames. Ethereal might do in a pinch too, though i have never used it for this.

Unless someone else has already tried monitoring the raw frames, I might give it a go tomorrow.

adavidm

[Mr. Worm~~]

I've made two test, one connect PC&PS2 using a cross utp wire, so physical negotiation takes place at 100mbps full duplex, so no CSMA/CD, in tother words no collisions...
Two, I've connect in between a Cisco Catalyst switch with fastethernet ports, and auto negotiation and the resut was 100mbps full duplex...
In both cases transfer speeds feel like 10Mbps / half duplex, about 5% of available link speed (about 650Kbps)...So I dont know where is the limitation, is not at physical layer, but could be at logical link control sublayer...
PC to PC I got more that 6500kbps...at least 10 times faster....

[Drakonite]

...The limitation is related to the IOP. You can only run so much through an IP stack and then through a filesystem driver on a 36Mhz processor.
Would it be possible to optimize some things to increase performance? Probably. Would it be possible to transfer at the full capacity of a 100mbps LAN? HA! Not even close.

[amuront]

Then why the PS2 Linux kit allows me to take advantage of the 100mbps network speed? How would it be different from homebrew?

[Drakonite]

Well, for one thing, what I've heard about ps2linux kit's network performance doesn't put it anywhere near the theoretical maximum of a 100baseT network.

Homebrew, commercial games, and essentially everything other than the ps2linux kit have the IP stack on the IOP. The PS2LINK kit however, just has a transport layer on the IOP. All the work is done on the EE, which means unlike with it being on the IOP, the IP stack is no longer the bottle neck, just pushing the raw bits through the IOP is. For just raw network performance it may seem like this is a better way to go, but it has a very detrimental effect to anything running on the EE (not to mention the mess of a driver setup it'd make).

Also keep in mind things such as how linux will cache as much drive activity as possible in ram before commiting to disk, which would greatly reduce the immediate strain on the IOP for short download bursts.

Remember that PS2IP uses LWIP, which probably isn't going to be the fastest IP stack in the world, but AFAIK no one has really benchmarked everything. I admit I may be a bit biased as I really do not like LWIP.

There has been talk of trying to find another IP stack, as LWIP is disliked by many, but it would be quite a bit of work for relatively little gain, so your guess is as good as mine as to whether it will happen ;)