Using the PiCalculator to calculate 20000 digits of pi in 1000 threads of
20 digits each on my grid came up with this:
Time Number of Threads completed
12:40:59 0 (Started)
12:41:04 33
12:41:05 39
12:41:34 190
12:42:02 268
12:42:24 307
12:43:26 400
12:45:29 493
12:47:27 600
12:51:16 701
12:55:45 800
13:01:43 900
13:07:20 960
13:08:10 970
13:09:22 980
13:10:40 990
13:20:47 998
13:27:54 999
14:59:59 1000 (Finished)
I previously ran 3000 digits with 25 digits per thread in 34 seconds. So
scaling up from that you would think it would take approx. 5 minutes for 20000.
I think this difference is because of the way in which I have set up the
grid (using version 1.0.2 of the SDK, Manager - database in Memory - and
Executor Service) on 250 computers. I have set the executor service to
start when theres no-one logged in (on boot and logout) and stop on login.
I would guess the problem in this case is that an executor is allocated a
thread and then the executor stopped (because someone is logging into the
machine). The Manager never reallocates the thread and so we have to wait
for the executor to be restarted (the person logs out of the machine) and
then the job to be done.
I recall there was some discussion of having a a re-scheduler in the
Manager so that the manager can re-issue the thread to another executor if
the executor heartbeat dies (i.e. the executor is stopped). Has that been
implemented in the later versions?
I'm not planning on upgrading all the executors to a later version for
another month or two (as part of the mid-semester rebuild of the computer
labs I'm in charge of) so I'll live with it for now.
-------------------------
Reece Arnott
Learning Environments Specialist
School of Business
University of Otago
Dunedin
New Zealand
[EMAIL PROTECTED]
-------------------------
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