[SPARK-32878][CORE] Avoid scheduling TaskSetManager which has no pending tasks #29750
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@tgravescs @jiangxb1987 @cloud-fan Any idea on this? |
mridulm
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Sep 14, 2020
mridulm
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Sep 14, 2020
tgravescs
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definitely seems like a good thing in general, I was a little worried about other side affects that happen in the scheduling loop but the only one I saw was with locality which doesn't matter since no pending tasks so I think its ok.
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Test build #128660 has finished for PR 29750 at commit
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dongjoon-hyun
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Sep 15, 2020
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+1, LGTM. It seems that @mridulm 's comment is the last one we need to do.
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Thanks all! I've addressed the comment. |
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Merged to master for Apache Spark 3.1.0 on December 2020. |
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Thank you, @Ngone51 and all! |
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Test build #128689 has finished for PR 29750 at commit
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What changes were proposed in this pull request?
This PR proposes to avoid scheduling the (non-zombie) TaskSetManager which has no pending tasks.
Why are the changes needed?
Currently, Spark always tries to schedule a (non-zombie) TaskSetManager even if it has no pending tasks. This causes notable problems for the barrier TaskSetManager: 1.
calculateAvailableSlotscan be called for multiple times for a launched barrier TaskSetManager; 2. user would see "Skip current round of resource offers for barrier stage" log message fora launched barrier TaskSetManager all the time until the barrier TaskSetManager finishes, which is quite confused.
Besides, scheduling a TaskSetManager always involves many function invocations even if there're no pending tasks.
Therefore, I think we can skip those un-schedulable TasksetManagers to avoid the potential overhead.
Does this PR introduce any user-facing change?
No.
How was this patch tested?
Pass existing tests.