[HECnet] Emulated XQ polling timer setting and data overrun

Johnny Billquist bqt at softjar.se
Thu Jun 5 09:26:48 PDT 2014


On 2014-06-05 02:38, Jean-Yves Bernier wrote:
At 4:59 PM -0700 4/6/14, Mark Pizzolato - Info Comm wrote:

Did you change the number of receive buffers?

That does not seem possible under RSX.

It is, but you need to do it in CFE. No way of dynamically changing at runtime.

That really only indicates that you're running on a platform which can
do Ethernet network I/O in a parallel thread.   Most platforms did not
use the threaded model previously.   Previously, in 3.9, Polling was
still necessary since the simulator didn't really support an
asynchronous I/O model.   The latest codebase has support for
asynchronous network AND disk I/O.   On the current codebase if you've
got threads available, then network reads and writes are performed
asynchronously and interrupts (I/O completion) is triggered with a few
microseconds of latency.   As I recall from earlier in these threads,
you're running under CentOS on VirtualBox. You didn't mention what
host OS you're running on.     In any case, the threaded model might
just work better in the virtual environment.


I have tested commit 753e4dc9 on Mac OS 10.6, no virtualization. Both
simh instances run on the same hardware. XQ set to different MAC
addresses, since this is now enforced.

Asynchronous network/disk IO may explain the uncommon transfer speed (I
have filled a   RM03 in seconds).

Interesting. I still have real network issues with the latest simh talking to a real PDP-11 sitting on the same physical network. So you seem to have hit sime other kind of limitation or something...

	Johnny

-- 
Johnny Billquist                                   || "I'm on a bus
                                                                  ||   on a psychedelic trip
email: bqt at softjar.se                         ||   Reading murder books
pdp is alive!                                         ||   tryin' to stay hip" - B. Idol



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