low slip throughput

low slip throughput

Post by Jeff Ram » Sat, 29 Jul 1995 04:00:00



I finally got my slip connection to work!

But now I have a very slow transfer rate problem.  Another person
I know has the same setup as me {we use the same slip server, and
our modems are both 14400bps}.  He tells me that he's able to achieve
28800bps, using CSLIP.  

I ran some tests last night, and my machine only achieves about
10500bps.  I set the rate of the device to 38400 in my dip script.

Anyone have any ideas?

--------------------------------------------------------------------
Jeffrey Ramin                     University of Wisconsin

608 262 1071                      1225 West Dayton
                                  Madison, WI  53706

 
 
 

low slip throughput

Post by Richard Kilgor » Sat, 29 Jul 1995 04:00:00





>[ ... lousy SLIP throughput ...]

>Same problem here. I have a Tadpole SPARCbook at home that (using the
>same 14.4Kbps modem, tele line, cable, SLIP server, even the comm
>program) gets upto 60% better throughput than my DX2-66/16M linux
>machine! The only potential culprit might be my UART, a lowly 16450
>which has no buffer.  Anybody know if I use a better I/O card (can't
>replace the chip since it's built onto my motherboard) if I'll improve
>my throughput significantly? Here's my serial parameters:

>    % setserial -a /dev/modem
>    /dev/modem, Line 1, UART: 16450, Port: 0x02f8, IRQ: 3
>    Baud_base: 115200, close_delay: 50, divisor: 0
>    Flags: spd_hi skip_test

The spd_hi flag can be a bad idea for a machine with a 16540 UART.
I'd suggest going with spd_normal, and you might even want to set
the port's speed at 19200.  I find that using the compression stuff
really doesn't make a very big difference, and with a slower UART,
you get MUCH WORSE performance from all of the overflows.

        Olah,

        - rick

--
Richard B. Kilgore
Summer Intern, Intel Santa Clara
Grad Student, University of Texas at Austin
WWW URL: http://lore.ece.utexas.edu/~rkilgore/


 
 
 

low slip throughput

Post by Matthew Lundbe » Mon, 31 Jul 1995 04:00:00



:
:Same problem here. I have a Tadpole SPARCbook at home that (using the
:same 14.4Kbps modem, tele line, cable, SLIP server, even the comm
:program) gets upto 60% better throughput than my DX2-66/16M linux
:machine! The only potential culprit might be my UART, a lowly 16450
:which has no buffer.  Anybody know if I use a better I/O card (can't
:replace the chip since it's built onto my motherboard) if I'll improve
:my throughput significantly? Here's my serial parameters:

Yes.  A 16450 or an 8250 will take much more machine resources
to drive.  They must interrupt the processor on each character,
and if a new one comes in before the processor's had a chance
to get the old, the old gets discarded.  16550A serial boards
run about $30, and most fast internal modems come with one.