Thread.priority= is effectively a no-op
I raised the following back in January:
Is it reasonable to expect the following to produce differing counts in the result array?
counts = [ 0 ] * 10
Thread.abort_on_exception = true
10.times do |i|
thread = Thread.new(i) do |index|
Thread.current.priority = index
counts[index] += 1
I get [6176, 6173, 6167, 6173, 6174, 6175, 6177, 6178, 6174, 6177]
I don't know the rationale behind, but at least on Linux:
- the default scheduling policy is SCHED_OTHER. Ruby does not explicitly specify scheduling policy.
- for SCHED_OTHER, min and max of priority is both zero
- the specified priority is rounded to zero
- as a result, no priority change happens
We have to ask Koichi if it's a bug or not.
Given this: (a) is it a Ruby bug, and (b) if not, should we remove the method, as it might confuse folks?
Updated by mame (Yusuke Endoh) over 11 years ago
- Assignee changed from mame (Yusuke Endoh) to ko1 (Koichi Sasada)
I have three choice:
(1) make Thread#priority= deprecated (or remove)
(2) add "Not available on all platforms." to its document
(3) very ad-hoc fix ruby-dev:33124 another way that I cannot think of
Please select :-)