Fast Ethernet and Linux Technical Details
I tested five Linux boxes connected via Fast Ethernet hub,
equipped with three SMC EtherPro cards, one 3c905 and four
Intel EtherExpress Pro 10/100.
The cable lengths are 65 meters (from hub to Torus and Net3),
38m to Mira and 1m to Zeus and Star. For testing aims the binary FTP transfer
of a 12MB file has been used. I transferred this file several times
in order to obtain maximum results. Firstly, some data.
| FTP Transfer | File to file |
File to /dev/null |
| Zeus -> Torus | 810 Kbytes/sec | 4.2 Mbytes/sec
|
|---|
| Torus -> Zeus | 6.1 Mbytes/sec | 5.7 Mbytes/sec
|
|---|
| Zeus -> Net3 | 3.9 Mbytes/sec | 7.8 Mbytes/sec
|
|---|
| Net3 -> Zeus | 8.6 Mbytes/sec | 8.6 Mbytes/sec
|
|---|
| Zeus -> Mira | 3.6 Mbytes/sec | 7.1 Mbytes/sec
|
|---|
| Mira -> Zeus | 8.6 Mbytes/sec | 8.6 Mbytes/sec
|
|---|
| Zeus -> Star | 3.4 Mbytes/sec | 8.5 Mbytes/sec
|
|---|
| Star -> Zeus | 7.3 Mbytes/sec | 8.3 Mbytes/sec
|
|---|
- Mira:
- P133 64 MB RAM, Linux 2.0.27 tulip.c:v0.10+0.72+0.01
eth0: smc9332 (DEC 21140 Tulip) at 0x6100
- Net3:
- P120 32 MB RAM, Linux 2.0.27 tulip.c:v0.10+0.72
eth0: smc9332 (DEC 21140 Tulip) at 0xe000
- Zeus:
- 2xPPro200 256 MB RAM, Linux 2.0.27 tulip.c:v0.10+0.72+0.01
eth0: smc9332 (DEC 21140 Tulip) at 0xd800
- Torus:
- P120 32 MB RAM, Linux 2.1.21 3c59x.c:v0.30-all
eth0: 3Com 3c905 Boomerang 100baseTx at 0x6000
- Star:
- P120 32 MB RAM, Linux 2.1.30 eepro100.c:v0.32
eth1: Intel EtherExpress Pro 10/100 at 0xe000
Some notes and conclusions:
No problems with SMC EtherPro cards. Transfer rate up to
8.6 Mbytes/sec seems reasonable for practical work.
I've got many troubles with 3COM 3c905 card. One can see
extremely poor transfer rate when receiving data.
Ifconfig shows RX errors and dropped packets.
I tried several different versions of
Donald Becker's 3c59x.c and boomerang.c drivers and experienced
no difference. As the transfer rate is much more better when
receiving data to /dev/null, one can suppose that a conflict
with IDE take place. No solution yet.
Intel EtherExpress Pro 10/100 is the cheapest one. There are
two problems with this card: (1) at one of my boxes with 3 such
cards the initialisation after reboot is unstable. Sometimes I need
ifconfig down/up some interfaces in order to make it operational.
(2) one of my boxes with this card sometimes (rarely) hangs under
the heavy RX traffic. It never happened when received to /dev/null
(it sounds that it is the same problem as with 3c59x.c driver, i.e.
interference between Ethernet and IDE drivers). It never happened
also at the boxes with only SCSI drives.
Linux with SMC EtherPro seems very stable. During 8 months
we had no any hangs or troubles under rather intensive traffic.
Our
main router Net3
is now capable to handle Fast Ethernet interface, two 10Mb
Ethernets (with 3c509 cards) and 115Kbps serial link. I didn't
noticed any overloads and delays. Two parallel FTP sessions
10Mb Ethernet -> Net3 -> Fast Ethernet from two different
10Mb Ethernets runs at the full speed (about 900 Kb/sec).
The CPU utilization is about 20-25 percents for this extremal
situation.
Comments and questions to Evgeny Rodichev,
[email protected]
Last updated 21.07.1997.
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