[ACT-R-users] Warning about upgrading to MacOS 10.15

[db30 at andrew.cmu.edu]

I've been working with 10.15 now and have some more information about
using ACT-R with it.

The current ACT-R standalone application for Macs will now work under
10.15.  It also works in 10.14 and 10.13 as well.  I assume that it
also continues to work in older versions too, but I don't have any
machines with those to test it on to be certain.

The version of Clozure Common Lisp available from the App Store now
only works in 10.15.  As I warned about yesterday, if you're using
the App Store version of CCL you should not apply the current update
if you're using any other Mac OS version.

I don't know if ACL or LispWorks will run under 10.15 because they
only make their 32-bit versions available for free trials.

SBCL does work under 10.15.  However, I encountered an odd issue with
running the normal ACT-R sources using SBCL on two machines (one
running 10.15 and one running 10.13) using multiple versions of SBCL.
The normal ACT-R version ran extremely slow compared to the single-
threaded version of ACT-R on the same machine using the same version
of SBCL.  It appears to be an issue with the threading resulting in
the processor just idling a lot.  Here are the results of timing a
short run of the zbrodoff task from the tutorial with the single-
threaded ACT-R:

* (time (zbrodoff-set))

              2 ( 8)      3 ( 8)      4 ( 8)
Block  1  2.320 ( 8)  2.807 ( 8)  3.320 ( 8)
Evaluation took:
  0.126 seconds of real time
  0.126219 seconds of total run time (0.123596 user, 0.002623 system)
  [ Run times consist of 0.010 seconds GC time, and 0.117 seconds non-GC time. ]
  100.00% CPU
  650 lambdas converted
  340,951,638 processor cycles
  35,463,872 bytes consed

and here's the same machine and same SBCL running the normal ACT-R
sources:

* (time (zbrodoff-set))

              2 ( 8)      3 ( 8)      4 ( 8)
Block  1  2.295 ( 8)  2.845 ( 8)  3.282 ( 8)
Evaluation took:
  71.418 seconds of real time
  1.138068 seconds of total run time (0.544565 user, 0.593503 system)
  [ Run times consist of 0.034 seconds GC time, and 1.105 seconds non-GC time. ]
  1.59% CPU
  628 lambdas converted
  192,833,028,057 processor cycles
  34,588,368 bytes consed

I don't see the same issue when using CCL on those machines,
and I also didn't see that problem under Linux or Windows with
the same versions of SBCL.  So, you may want to be careful when
using SBCL on Macs.


Hope that information is helpful,
Dan