network perf : em driver ?
patpro at patpro.net
Fri Jan 12 01:27:51 PST 2007
I'm the happy owner of a Tyan Tiger i7520SD motherboard, sporting two
ethernet ports using a Intel 82571EB GbE controller and running
FreeBSD 6.2 RC1. FreeBSD uses the em driver for this ports:
em0: <Intel(R) PRO/1000 Network Connection Version - 6.2.9> port
0x2000-0x201f mem 0xd8020000-0xd803ffff,0xd8000000-0xd801ffff irq 16
at device 0.0 on pci3
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255
media: Ethernet autoselect (1000baseTX <full-duplex>)
The box uses its 100baseT fxp driven eth port for internet access,
and shares this access with a Mac OS X plugged on the em0 interface.
I've set up pf with firewall and nat rules to act as a gateway. Both
machines are in "Ethernet autoselect (1000baseTX <full-duplex>)" and
linked with a direct ethernet wire.
File transfert through em0 looks quite slow : at best 17 MB/s (scp
gives better results than http, tested with a 120MB file)
File copy, from one HDD to another or from one HDD to /dev/null,
ranges from 30 to 48 MB/s on the FreeBSD side (SATA HD).
I would like to know if there is a good method to find the bottleneck
and to get rid of it. How comes my GbE is so slow ?
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