Gigabit network performance problems with Fedora Core 2

[Axel Suppantschitsch]

Hiya,

	I recently upgraded my Network Infrstructure to Gigabit Ethernet as
well as my Network Server form Fedora Core 1 to Fedora Core 2. So far so
good...

After the first network performance tests with netperf and netpipe I got
really disappointed, as the diskless network performance is around 200
Mbit/s.

A linux server with following specifications is used in this szenario:

* Hardware
	Asus A7V-266E
	Athlon 1800 XP
	512MB RAM
	eth0: Intel Pro/1000 MT Desktop Adapter, PCI (1 Gbit Fullduplex)
	eth1: Realtek 8139, PCI (100Mbit Fullduplex)
	Permedia 2 Graphics Adapter, PCI
	hda: Maxtor 80GB IDE HD (UDMA5)
	hdc: IBM 120GB IDE HD (UDMA5)
* Software
	Fedora Core 2 (latest patchlevel)
	Kernel 2.6.8-1.521
	e1000 driver, version: 5.3.19-NAPI

* Switch: D-link DGS-1008D Gigabit Switches

* Cables: Cat5 shielded TP cables tested with Fluke for Cat5 compliance

The hardware should be ok, as I tested eth0 within my Windows XP Workstation
and the card performed well with 560Mbit/s without tuning. The two Windows
XP workstations with onboard Intel Pro/1000 CT adapters even showed a
performace of 800Mbit/s without tuning.
So I guess the bottleneck has to be somewhere within the Fedora Core 2
System.

I also checked the CPU load during the tests, which peaked around 20%, so
this can't be the problem either. The card is configured correctly, as
ethtool eth0 shows following output:

Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised auto-negotiation: Yes
        Speed: 1000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: umbg
        Wake-on: g
        Current message level: 0x00000007 (7)
        Link detected: yes

I tried almost everything now, so I have any further ideas...

Any suggestions please?

Regards,

Axel.