[MESOS-3997] Switch to fixed-point for resources

• Type: Epic
• Status: Accepted
• Priority: Major
• Resolution: Unresolved
• Component/s: allocation, master
• Labels: mesosphere resources
• Epic Name: Fixed Point Resources
• Assignee: Unassigned
• Reporter: Neil Conway
• Created: 23/Nov/15 20:02
• Updated: 27/Jan/16 18:43

Description

Using floating point for resources is problematic, because roundoff and precision errors when doing resource math can produce unexpected results.

Instead, we should probably adopt a fixed-point representation: e.g., CPU resources will be measured as an integer number of fractional CPUs (e.g., 25 deci-CPUs == 2.5 CPUs).

Issue Links

• is duplicated by: MESOS-3992 Change Doubles to Ints in the protobufs
• relates to: MESOS-1187 precision errors with allocation calculations
• relates to: MESOS-3090 Calculated CPU should be rounded
• relates to: MESOS-4071 Master crash during framework teardown (Check failed: total.resources.contains(slaveId))
• relates to: MESOS-2635 Web UI Display Bug when starting lots of tasks with small cpu value
• relates to: MESOS-3990 Unexpected reservation results due to floating point error
• relates to: MESOS-4018 Enhance float-point operation in Mesos
• relates to: MESOS-3341 Introduce Resource Resolution
• relates to: MESOS-3552 CHECK failure due to floating point precision on reservation request