Spontaneous Slowdowns on SMP System

Jim Morris jim@morris.net
Thu Aug 19 12:31:47 1999

Hi all.

I have a dual-processor system running the Linux 2.2.10 kernel.  I am
using a very recently acquired LinkSys Etherfast 10/100 PCI card, based on
the PNIC-II chipset.   When running an SMP-enabled kernel, things will run
great for a while, and then I suddenly start getting calls from users
complaining that the "network is slow".  Sure enough, I can do a telnet,
or a domain logon to Samba from a Windows PC, and it appears as though the
network connetion to the server is running at about 1/100th speed.  I.e.
everything works, but VERY slowly.

If I take the network down on the server, and rmmod the tulip module, and
then run "/etc/rc.d/init.d/network start" to bring networking backup,
everything will be fine again for a while.  All in all, the slowdowns
occur somewhat randomly, at least once or twice per day.

If I build and run a non-SMP kernel (and tulip driver), then everything
runs fine indefinitely. In fact, I went on vacation last week, and left
the server running the uniprocessor kernel, and its been running for
almost 2 weeks solid with no network slowdowns.

I have tried the Linksys-modified driver that came on the floppy with the
card (a modified 0.90f), as well as 0.91, and the latest test version,
0.91g. The problem occurs with all 3 drivers.

I *thought* I had seen mention of this, but looking through the mailing
list archives on Tux, as well as the newsgroup archives on Dejanews
doesn't turn up anything.

Any help will be greatly appreciated!

| Jim Morris  |  jim@morris.net |