I've noticed just today that all doesn't seem to be well with 16550 
serial ports on i386 hardware. This is running a NetBSD 1.6H Kernel.

My machine is a AMD K6-200 and used to be able to keep up with 19200 
baud or more without any handshaking (this bit is imposed on my by the 
external hardware). Today I notice that it can't even keep up at 9600 
baud which is as low as my external hardware goes.

Did the interrupt latency just take a large leap or has there been 
another change in say the last 6 weeks that may have caused this? I'm 
not too sure which kernel was last OK. 1.6D seems to show the same 
behaviour and I don't have an older one around anywhere.

Any ideas?

Thanks

Alex.