Subject: Re: [q] A Mac is crashing my NetBSD/i386 box
To: Ken Wellsch <kwellsch@link.link-systems.com>
From: Peter Bentley <peter.bentley@nomura.co.uk>
List: port-i386
Date: 06/19/1998 15:00:21
Ken Wellsch wrote:
> | On Jun 18, Ken Wellsch wrote
> | > Within what seems like a few seconds I've consumed all my mbuf space,
> | > crippling my server system.  netstat claims I've got the expected 16Kb
> | > in the queue.
> | >
> | > The same server to another system, e.g. W95, W/NT, Linux does not have
> | > this problem - the NetBSD seems to be properly blocking my writes.

Have you been able to verify (eg with truss) that your writes are being
blocked? I know that the 16K in the send queue points to that, but if
the data consuming the mbufs isn't coming from your app, and if the Mac
isn't sending data to you then it must be triggering some very odd
breakage inside the TCP stack, perhaps by advertising dumb window sizes.

> I have watched via "netstat -m" as the percent used number grows
> rapidly when I'm running my application.  I mean rapidly too.  I
> ran "netstat" as quickly as I could and the %-used increased something
> like 6% to start, 23%, 56%, 73% and that is when I killed the process.

Perhaps if you could capture the start of the TCP stream with tcpdump,
one of the TCP gooroos can spot what the problem is...

Pete.