Bug in Bob Supnik's Emulator!

[Steven M. Schultz]

Tim -

> From: Tim Shoppa <shoppa at alph02.triumf.ca>
> On a cow orker's 200 MHz Pentium Pro, Bob Supnik's emulator (compiled

	He's in the "dairy business"? :-) :-)

> with gcc and running under Linux) is about twice as fast as a real
> 11/73 for most CPU-intensive operations.  Speeds for I/O based
> operations can range from incredibly faster to incredibly slower

	Ok - I finally got around to retrying Bob's emulator.  This is using
	gcc 2.8.1 under BSD/OS 3.1 with a PPro 200 and the Dhrystone 2.1 (C
	language version) program.

	Running under the emulator I get 555 dhrystones/second.  On a real
	11/73 I see 664 dhrystones/sec.

	I/O operations are faster but I suspect a some of that is
	due to Ultra-Wide Barracuda drives vs. HP 3724 and an Emulex UC08.

> than a real -11, of course, and a lot of the interrupt and device
> priority schemes seem seriously out of whack with how a real PDP-11

	The line frequency clock seems to be acting strange.    When running
	the dhrystone program I see:

Measured time too small to obtain meaningful results
Please increase number of runs

	EVEN THOUGH the (wall clock) run time for 20000 dhrystones was 36 
	seconds.

> The same emulator running on a 7-year-old 133 MHz DEC Alpha is about

	I recall when the DEC rep here brought in one of the first 150mhz
	Alpha systems.  Thought it was awesome that a machine could do a
	3 phase build of GCC in about 1 hour.  Ummm, today a PPro can do it
	in about 15 or 20 minutes ;)

	Other benchmarks of possible interest:

	A recompile of the 2.11BSD C compiler:

11/44	9min 20sec
11/73   9min 33sec
11/93   6min 43sec
emulated PDP-11 5min 25sec (BUT the 'time' reported with "time make" was 10min
			    4 sec)

	the 44 and 73 are suprisingly close because the 44 was hobbled with
	RA81s on a UDA50 while the 73 had a HP3724S on Emulex UC08.  Alas,
	the RA81 died so I no longer have a 44 to test with (until I get a RA9x
	or something myself since the support department refused to do it).

	Interesting that the emulated one is faster on this test even though
	the dhrystone rating is about 20% slower.

	Steven


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