"locking down" user I/O buffers

[Steve Nuchia]

Greetings.  I have written a high-performance serial driver
for sysV/386 and other PC-based unix systems.  It works well
enough given that it was written without recourse to licensed
source code, but I would like to make it faster.

In the current incarnation it passes all data through the
line discipline, incurring several function calls per clist
block.  It is also context switching too often.  Since the
major case of interest is uucico and other raw mode applications
I was trying to see how to have the interrupt routine work
directly from user buffers.  I am using the National 16550A
replacement UART wich has 16 bytes of FIFO on chip in each
direction, so significant performance should be achievable.

Is there a portable way in systemV (.2 et seq. preferably)
to aquire a user space buffer that can be referenced at
interrupt time?  Barring that, can someone tell me how
to do it specifically in the V.3 for 386 environment?

	Thank you.
-- 
Steve Nuchia	      South Coast Computing Services
uunet!nuchat!steve    POB 890952  Houston, Texas  77289
(713) 964 2462	      Consultation & Systems, Support for PD Software.