SIS900 performance/autonegotiation issue

From: André Weidemann (Andre.Weidemann@web.de)
Date: Wed Mar 05 2003 - 06:52:35 EST


Hi,
I have an Elitegroup K7SEM mainboard with onaboard VGA and onbaord NIC.
The NIC is an SIS900. The mainboard is equipted with 128MB RAM and I am
using the onbaord VGA with 8MB share Memory.
I am using the latest patch from kernel.org, 2.4.21-pre5, and the stable
2.4.20 for testing. Both show the same behavior. The 2.4.21-pre5
sometimes starts the sis900 at 10Mbit autonegotiation. All other NIC's I
tested on the very same cable always came up at 100Mbit and had full
performance.
The machine I am having trouble with is working as a video server with a
Technotrend DVB-S card and is booted via Etherboot 5.1.3. The Ehterboot
ROM resides inside the BIOS ROM. The machine is starting up via DHCP,
TFTP and get it's root file system via NFS.
The problem is that the network speed on the SIS900 is "asymmetrical". I
am using netio 1.13 to do performance measuring. When I start "netio -s"
on the video machine and "netio 192.168.0.20" on the server I get the
following results at 100Mbit(autonegotiantion)

TCP/IP connection established.
Packet size 1 k bytes: 61169 bytes/sec
Packet size 2 k bytes: 60416 bytes/sec
Packet size 4 k bytes: 59392 bytes/sec
Packet size 8 k bytes: 64710 bytes/sec
Packet size 16 k bytes: 54067 bytes/sec
Packet size 32 k bytes: 68811 bytes/sec

When I start "netio -s" on the server and "netio 192.168.0.42" on the
video machine I get the following at 100Mbit (autonegotiantion):

TCP/IP connection established.
Packet size 1 k bytes: 3123 k bytes/sec
Packet size 2 k bytes: 2852 k bytes/sec
Packet size 4 k bytes: 3069 k bytes/sec
Packet size 8 k bytes: 3927 k bytes/sec
Packet size 16 k bytes: 4867 k bytes/sec
Packet size 32 k bytes: 3721 k bytes/sec

Besides the asymmetrical effect the speed is still very slow for the
fast side. A cheap Realtek 8139 card plugged into the video machine and
using the very same cabel (Cat 5 double shielded, 25m to switch) gets a
symmetrical speed of 10-11Mbyte.
The NIC inside the server is a 3COM 3C905-TX-M at 100Mbit.

After that I set the speed for the SIS900 manually to 10Mbit using
"mii-tool -F 10baseT-FD".
With "netio -s" on the video machine the results now look like this:

TCP/IP connection established.
Packet size 1 k bytes: 1081 k bytes/sec
Packet size 2 k bytes: 1099 k bytes/sec
Packet size 4 k bytes: 1040 k bytes/sec
Packet size 8 k bytes: 1109 k bytes/sec
Packet size 16 k bytes: 1099 k bytes/sec
Packet size 32 k bytes: 1085 k bytes/sec

Doing it the other way round (netio -s on the server) results in this:

TCP/IP connection established.
Packet size 1 k bytes: 896 k bytes/sec
Packet size 2 k bytes: 902 k bytes/sec
Packet size 4 k bytes: 857 k bytes/sec
Packet size 8 k bytes: 872 k bytes/sec
Packet size 16 k bytes: 869 k bytes/sec
Packet size 32 k bytes: 869 k bytes/sec

Any help in getting the sis900 to full speed or at least to 3Mbyte in
both directions are greatly appreciated.

  André.

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This archive was generated by hypermail 2b29 : Fri Mar 07 2003 - 22:00:01 EST