[SERVER-50290] Enforce stronger limits on task splitting Created: 13/Aug/20  Updated: 29/Oct/23  Resolved: 13/Aug/20

Status: Closed
Project: Core Server
Component/s: Testing Infrastructure
Affects Version/s: None
Fix Version/s: 4.4.1, 4.7.0

Type: Improvement Priority: Major - P3
Reporter: David Bradford (Inactive) Assignee: David Bradford (Inactive)
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File Screen Shot 2020-08-19 at 9.32.11 AM.png    
Issue Links:
Backports
Backwards Compatibility: Fully Compatible
Backport Requested:
v4.4
Sprint: DAG 2020-08-24
Participants:

 Description   

We have found that splitting tasks too aggressively we can create a lot of extra work in setup and teardown of the tests, which causes us to split tasks even more, which leads to more setup and teardown. By limiting the number of sub-tasks we create, we can contain the growth of the setup/teardown overhead.

In some exploration, it appears that a max split of 3 gives us similar makespans as we currently have, which minimizing the overhead of additional tasks.


As a server engineer,
I want tasks in my patch builds split optimally,
So that I can minimize the amount of time I spend waiting for a patch build.


AC:

  • All required builders set the max_sub_suites value to 3.
  • Non-required builders set the max_sub_suites value to 1.


 Comments   
Comment by Harris Hoke (Inactive) [ 19/Aug/20 ]

Just for the last 24 hours, we didn’t even hit max_hosts on either rhel62 distro, much less maxing out for those long nightly plateaus we’ve come to expect. With one day of this I would be worried it was just a fluke due to fluctuations in volume, but two days is extremely promising to me!

Comment by Githook User [ 13/Aug/20 ]

Author:

{'name': 'David Bradford', 'email': 'david.bradford@mongodb.com', 'username': 'dbradf'}

Message: SERVER-50290: Cap number of subtasks generated

(cherry picked from commit 53b690294d160a6e1cd0f4a004cb55c4835a48b8)
Branch: v4.4
https://github.com/mongodb/mongo/commit/7ef0e225846a25821325bd24fc66d29f4c503385

Comment by Githook User [ 13/Aug/20 ]

Author:

{'name': 'David Bradford', 'email': 'david.bradford@mongodb.com', 'username': 'dbradf'}

Message: SERVER-50290: Cap number of subtasks generated
Branch: master
https://github.com/mongodb/mongo/commit/53b690294d160a6e1cd0f4a004cb55c4835a48b8

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