[MESOS-9504] Use ResourceQuantities in the allocator and sorter to improve performance.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.8.0
• Component/s: allocation
• Labels: performance
• Epic Link: Allocator performance improvement.
• Sprint: Resource Mgmt RI12 Sp 43
• Story Points: 3
• Assignee: Meng Zhu
• Reporter: Meng Zhu
• Created: 31/Dec/18 18:53
• Updated: 01/Apr/19 19:45
• Resolved: 01/Apr/19 19:45

Description

In allocator and sorter, we need to do a lot of quantity calculations. Currently, we use the full Resources type with utilities like createScalarResourceQuantities(), even though we only care about quantities. Replace Resources with ResourceQuantities.

See:

https://github.com/apache/mesos/blob/386b1fe99bb9d10af2abaca4832bf584b6181799/src/master/allocator/sorter/drf/sorter.hpp#L444-L445
https://reviews.apache.org/r/70061/

With the addition of ResourceQuantities, callers can now just do ResourceQuantities.fromScalarResources(r.scalars()) instead of using Resources::createStrippedScalarQuantity(), which should actually be a bit more efficient since we only copy the shared pointers rather than construct new `Resource` objects.