Troubles with em on FreeBSD 7

[mike at sentex.net]

On Sat, 03 May 2008 18:28:55 +0300, in sentex.lists.freebsd.net you
wrote:

>Hi!
>
>I'm running a SMP FreeBSD box with mpd5 on it.
>
># uname -a
>FreeBSD xxx.xxxxxxxxx.xxx 7.0-STABLE FreeBSD 7.0-STABLE #0: Sat May  3 
>12:40:02 EEST 2008     xxxxx at xxx.xxxxxxxxx.xxx:/usr/obj/usr/src/sys/XXXX 
>  amd64
>
># mpd5 -v
>Version 5.1 (root at xxx.xxxxxxxxx.xxx 09:53  1-May-2008)
>
>Somehow em0 begins to eat all CPU time of one core.
>

A new version of the em drivers went into the tree Friday.

>dev.em.0.%desc: Intel(R) PRO/1000 Network Connection Version - 6.7.3

dev.em.0.%desc: Intel(R) PRO/1000 Network Connection 6.9.0
dev.em.0.%driver: em
dev.em.0.%location: slot=0 function=0
dev.em.0.%pnpinfo: vendor=0x8086 device=0x108c subvendor=0x15d9
subdevice=0x108c class=0x020000
dev.em.0.%parent: pci13
dev.em.0.debug: -1
dev.em.0.stats: -1
dev.em.0.rx_int_delay: 0
dev.em.0.tx_int_delay: 66
dev.em.0.rx_abs_int_delay: 66
dev.em.0.tx_abs_int_delay: 66
dev.em.0.rx_processing_limit: 100

Also, post some of the stats.  Do a 
sysctl -w dev.em.1.stats=1
to all of your em nics

em1: Excessive collisions = 0
em1: Sequence errors = 0
em1: Defer count = 0
em1: Missed Packets = 0
em1: Receive No Buffers = 0
em1: Receive Length Errors = 0
em1: Receive errors = 0
em1: Crc errors = 0
em1: Alignment errors = 0
em1: Collision/Carrier extension errors = 0
em1: RX overruns = 0
em1: watchdog timeouts = 0
em1: RX MSIX IRQ = 0 TX MSIX IRQ = 0 LINK MSIX IRQ = 0
em1: XON Rcvd = 0
em1: XON Xmtd = 0
em1: XOFF Rcvd = 0
em1: XOFF Xmtd = 0
em1: Good Packets Rcvd = 71949
em1: Good Packets Xmtd = 2507
em1: TSO Contexts Xmtd = 369
em1: TSO Contexts Failed = 0

And are you using gigabit or fastE. If fastE, try disabling TSO as
some people have said they have problems with it at 100Mb. 

	---Mike