> One request at the end of all this: if someone still has problems
> with overflows on x86 machines can they please give a very accurate
> description of the situation (software, hardware and processes that
> are running) in which the overflows occur.

I can try :) Hardware is an 25 MHz 80386 w/387, 4MB RAM, one IDE hard
drive, some serial port card with two 16550 ports, Olicom NE2000 clone
ethernet card, 3Com Etherlink II ethernet card. The network traffic is
extremely light... I'm too cheap to get a real ethernet hub and am
using the 386 as my "hub"... three computers total. It's running a May
17 NetBSD-current kernel, 115200 baud pppd connection (over a 64K ISDN
line). I've got NAT turned on in the kernel, and if I ftp from another
machine, using the 386 as the gateway (ISP <--PPP--> 386 <--NE2000-->
Pentium), I get about 10 silo overflows/minute. However, if I ftp
directly from the 386 (ISP <--PPP--> 386), I get maybe one overflow in
10 minutes. If, instead of using NAT, I run socks5 on the 386 and
connect through that, I get about one overflow per minute.

I also have a 100MHz Pentium, 48MB RAM, 53c810 SCSI controller with
two drives, 3c595 ethernet, two 16550 serial ports. I can usually run
both ports at 115200 baud and not see any problems, but I get silo
overruns fairly often with a single 57600 baud PPP connection over a
null modem cable if the Pentium's a NFS server (with the client being
the other end of the PPP link). Deflate compression was turned on for
the PPP link, if it matters...

So, it looks like at least on my machines, the com driver isn't too
bad (although if you can get 115200 on a 486DX2-66 w/8250 ports, it
seems like I should be able to do the same on my 386-25 w/16550 :)
Other parts of the system seem to block out interrupts for too long
though...

Name: Dave Huang     |   Mammal, mammal / their names are called /
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