Ethernet nic

Paul Civati paul at
Tue Oct 15 11:57:12 BST 2002

=?iso-8859-1?q?Sam=20Pikesley?= <samdavidpikesley at> wrote:

> > Intel EtherExpress Pro/100 for ethernet.
> Hmm, I had a lot of grief with one of these in my firewall, kept
> getting strange 'no buffer space available' errors... swapped it
> out for an old NE2000 and the problem went away...

This implies that some of the kernel buffers were running out
perhaps?  Maybe you needed to add NMBCLUSTERS to your kernel config
or increase maxusers, what version of FreeBSD?  Recent versions
auto-scale maxusers so I don't think you should need to do this..

# Set the size of the mbuf KVM reservation, in clusters.  This is scaled
# by approximately 2048 bytes.  The system will auto-size the mbuf area
# to (512 + maxusers*16) if this option is not specified.
# maxusers is in turn computed at boot time depending on available memory
# or set to the value specified by "options MAXUSERS=x" (x=0 means
# autoscaling).
# So, to take advantage of autoscaling, you have to remove both
# NMBCLUSTERS and MAXUSERS (and NMBUFS) from your kernel config.
options         NMBCLUSTERS=1024

# Set the number of mbufs available in the system. Each mbuf
# consumes 256 bytes. The system will autosize this (to 4 times
# the number of NMBCLUSTERS, depending on other constraints)
# if this option is not specified.
options         NMBUFS=4096

> > very cheap stuff that is Realtek 8139 based.
> And I've used these both at home and at work with no
> trouble ever... YMMV ;)

My understanding is that they'll fall over under high load.


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