Poor performance with my gigabit card?

GetCool

I have a Gentoo box running samba and a Windows XP machine directly connected with a crossover cable. Both machines have SMC9452TX V.2 gigabit NICs (I compiled support for the "Marvell Yukon / SysKonnect SK-98xx" chipset into my kernel, which specifically lists this card in the help screen). The cable is cat 5e, and I made it myself; the machines are sitting right next to each other so it's only about 2' long. I doubt that is the problem because I make cables all the time at my job and I am very careful, but I am not ruling out this possibility.

Anyway, I am getting (what I think is) poor performance. I'm using the latest Windows drivers for the card and I compiled support for this chipset into my 2.6.4-rc2-love1 kernel. I don't know if it can be trusted, but the task manager in Windows never shows higher than 12% network utilization when I am copying large amounts of data from my Windows machine to my samba share. Anyhow, I just copied ~12 GB of FLAC files over and it took approximately 14-15 minutes.

I am definitely going to try changing the cable, but I just wanted to know if this could be some sort of hardware issue. Also, it would be nice to find some linux utility that can monitor network utilization - any suggestions?

Thanks.

rockfly · Apprentice Joined: 27 Apr 2003 Posts: 179

copying with windows can slow down the proces, try to copy from a linux system to a linux system

GetCool · Posted: Thu Mar 11, 2004 10:05 pm Post subject:

sigSEGV2003 · Posted: Fri Mar 12, 2004 4:34 am Post subject:

IMO, that seems fairly good. Would be about 133Mbps. How fast are your hard drives?

sigSEGV2003 · Posted: Fri Mar 12, 2004 4:36 am Post subject:

Try bwmon or iftop to monitor your utilization.

GetCool · Posted: Fri Mar 12, 2004 5:28 am Post subject:

eNTi · Posted: Thu Apr 29, 2004 10:47 pm Post subject:

lol? i'm getting 5-7MByte/s on my gigabit network!!!
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Mnemia · Guru Joined: 17 May 2002 Posts: 476

How slow are the machines? On some fast machines I was able to get the Gigabit network to transfer up to about 750 Mbps, but on some older 600 MHz PIII machines I could only get the transfer rate up to about 350-400 Mbps. Things like the speed of your memory bus might make a difference.

You also might consider looking into some TCP performance tuning stuff, but I kinda doubt that that is the problem. Since your "network" probably has almost no latency it's probably not exceeding the TCP window size etc.

Try using tcpdump/Ethereal and trying to see if any weird stuff is going on, like heavy fragmentation.

MrMullen · n00b Joined: 24 Jan 2003 Posts: 27

The default networking tuning was not setup for 1000 Mbit. You should really tune out the TCP/IP stack before you conduct tests. I have worked with 1000Mbit in a enterprise eviroment and the default tuning for Linux is pretty bad. However, the good news is that there is a buttload of information to be found and it easy to get this tuning information in the stack without rebooting.

Pax-UX · n00b Joined: 20 Feb 2004 Posts: 65

I'm currently have the same problem with my linux 2.4 server running PIII 750 and 1Gb card, ATA100/133 a mix of each. Max speed for a file transfer is 5.7MB sometimes up to 7MB max, but mostly 5.7.

Did you manage to fix your problem with speed? As I don't think its a hard drive issue on my system. Do you know the links to any good TCP stack tunning guides?

Pax-UX · n00b Joined: 20 Feb 2004 Posts: 65

I found my problem, all the transfers were going through the SSH daemon for some reason, so I was maxing out my CPU 100% on my 750Mhz PIII. I ran iftop and then checked the normal top at the same time and saw that it was a CPU limitation. I'm going to look into removing the need for SSH on the transfers, as I do most of this stuff with rsync.

Paladine01 · Posted: Tue Aug 10, 2004 2:53 pm Post subject:

Try to enable Jumbo Frames on your card. An mtu around 9000 is desirable. It will ease the burden on your CPU and increase your network utilization.

Pax-UX · n00b Joined: 20 Feb 2004 Posts: 65

I have a 1Gb CNet 5 Port hub for the servers with a link to a normal 24 port 100Mb hub. Would this change effect all comunication with them, as I have little experence chaning the MTU setting? Also do you know if you need to have a hub that will support this? (i.e. is this non-standard? or just a new way of looking at network optimization? I've read a little before about Jumbo packets but was unsure if it would be compatable)