https://www.rosettacode.org/wiki/Metered_concurrency
I wanted to put together a more serious J implementation of the
rosettacode metered concurrency task.
Unfortunately, either (a) I do not understand how the threading
primitives are supposed to work, or (b) they are not working properly.
metcon=: {{
lock=: 10 T. 0
sleep=: 6!:3
metcon=: {{
lock=: 10 T. 0
sleep=: 6!:3
task=. {{
11 T. lock;_ NB. wait
sleep 2
echo r=.'Task ',y,&":' has the semaphore'
13 T. lock NB. release
r rplc 'has';'had'
}}
0&T.@'' each i.0>4-1 T.'' NB. ensure at least four threads
r=. task t.''"0 i.10 NB. dispatch 10 tasks
#each r NB. wait for completion
14 T. lock NB. discard lock
r
}}
I expect this to take about 20 seconds (because of the use of 6!:3)
and run ten tasks in 3 of the four guaranteed threads.
Instead, what I get is this:
metcon''
Task 1 has the semaphore
Task 3 has the semaphore
Task 5 has the semaphore
Task 7 has the semaphore
Task 9 has the semaphore
|value error
| #each r
So it looks like half of my tasks are getting lost somewhere, and it
looks like all of the results from those tasks are getting lost
somewhere.
JVERSION
Engine: j904/j64avx2/windows
Beta-d: commercial/2022-05-19T20:39:35
Library: 9.04.01
Qt IDE: 2.0.3/6.2.4(6.2.4)
Platform: Win 64
Installer: J904 install
InstallPath: c:/other/j904
Contact: www.jsoftware.com
Thanks,
--
Raul
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