PCIe vs PCI (was: Re: FreeBSD bind performance in FreeBSD 7)

Dieter freebsd at sopwith.solgatos.com
Mon Mar 3 22:38:59 UTC 2008


> Is there a way to tell from dmesg or pciconf that something is
> PCIe rather than PCI?  The onboard stuff could be either.

The secret appears to be
	pciconf -l -v | grep -i express

device   = 'BCM5750A1 NetXtreme Gigabit Ethernet PCI Express'

This bge(4) Broadcom chip had problems in 6.0 but works well in 6.2.
The critical part for my application is not getting the maximum
number of packets per second, but in not dropping any, and
getting them acked rapidly.  The closed source "black box" on the
other end of the wire has a buggy network stack, a *way* too small
transmit buffer, and generates data in real time that I have only
one chance to capture.

The remaining problem is that other device drivers can lock it out.
For example:
	http://www.freebsd.org/cgi/query-pr.cgi?pr=118093


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