On Tue, May 01, 2001 at 07:08:46PM -0400, Steve Bellovin wrote:
>
> Is there any reason (other than memory consumption) to refrain from 
> changing COM_RING_SIZE from 2048 to, say, 32768?  The comments indicate 
> that it's patchable, but has to be a power of 2.  It's used as the arg 
> to malloc(); are there limits to how large a block kernel malloc() can 
> allocate?

There should be no problems increasing it to any size you want, as long
as malloc() succeeds.

> My concern is the data rate of the Novatel "Merlin for Ricochet" PCMCIA 
> modem.  Linux has problems with its data rate (for details, see
> http://homepages.nyu.edu/~gmp216/nrm6842/bigfastuart.html); in a very 
> brief test today, I saw some indications that NetBSD was overflowing 
> that buffer as well.

Unless you got `silo overflow' or `ibuf flood' messages, that's not the
problem, or the hardware isn't reporting overflows.  It also seems a
little more suspicious since I *know* that we can keep up with a UART
running at 115200 baud, and Ricochet maxes at not much more than that.

So, I doubt this is going to help you, but I would need better
information to say anything else about it.