em driver input errors

[alexpalias-bsdstable at yahoo.com]

--- On Wed, 8/5/09, Marat N.Afanasyev <amarat at ksu.ru> wrote:

> From: Marat N.Afanasyev <amarat at ksu.ru>
> Subject: Re: em driver input errors
> To: alexpalias-bsdstable at yahoo.com, "freebsd-stable at freebsd.org >> FreeBSD-STABLE Mailing List" <freebsd-stable at freebsd.org>
> Date: Wednesday, August 5, 2009, 11:47 PM
> alexpalias-bsdstable at yahoo.com
> wrote:
> > 
> > kern.ipc.nmbclusters=655360
> > 
> do you have enough mbufs? look for mbuf clusters value in
> netstat -m output. if 'current' is near to 'total' you'll
> have drops of input packets. and take a look to 'jumbo
> clusters' in netstat -m too.
> 
> -- SY, Marat
> 

As mentioned in my initial mail, I did tune nmbclusters (you might say it's excessively high, 655360, but I still have 2.5 GB free memory on that machine.  I forgot to mention, MTU is 1500 on all vlans, so there's no need for jumbo frames, only VLAN_MTU flag on the interfaces.  All interfaces have:

em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
        ether 00:14:22:xx:xx:xx
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active


Here's the output from netstat -m for reference:

> netstat -m
16390/9350/25740 mbufs in use (current/cache/total)
16388/7938/24326/655360 mbuf clusters in use (current/cache/total/max)
16388/7932 mbuf+clusters out of packet secondary zone in use (current/cache)
0/151/151/12800 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/6400 9k jumbo clusters in use (current/cache/total/max)
0/0/0/3200 16k jumbo clusters in use (current/cache/total/max)
36873K/18817K/55691K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/0/0 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
0 calls to protocol drain routines