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Wangda Tan commented on YARN-4287: ---------------------------------- Some suggestions 1) RACK_LOCALITY_EXTRA_DELAY -> RACK_LOCALITY_DELAY, same as configuration property name (rack-locality-delay) 2) Do you think if is it a good idea to separate old rack-locality-delay computation (using getLocalityWaitFactor) and new rack-locality-delay config? Now rack-locality-delay = min(old-computed-delay, new-specified-delay), since the getLocalityWaitFactor has some flaws, I think we can make this configurable so user can choose to use specified or computed. Pseudo code may look like: {code} if type is OFF_SWITCH: if rack-locality-delay specified: delay = rack-locality-delay else: delay = computed-locality-delay else if type is RACK_LOCAL: delay = min(node-locality-delay, computed-or-specified-rack-locality-delay) {code} 3) bq. When we're getting rackLocal assignments, subsequent rackLocal assignments should not be delayed +1 to the fix, since this is a behavior change, do you think if we need to make this configurable? This change could lead to #node-local container allocation decreasing in some cases. Thanks, Wangda > Capacity Scheduler: Rack Locality improvement > --------------------------------------------- > > Key: YARN-4287 > URL: https://issues.apache.org/jira/browse/YARN-4287 > Project: Hadoop YARN > Issue Type: Improvement > Components: capacityscheduler > Affects Versions: 2.7.1 > Reporter: Nathan Roberts > Assignee: Nathan Roberts > Attachments: YARN-4287-v2.patch, YARN-4287.patch > > > YARN-4189 does an excellent job describing the issues with the current delay > scheduling algorithms within the capacity scheduler. The design proposal also > seems like a good direction. > This jira proposes a simple interim solution to the key issue we've been > experiencing on a regular basis: > - rackLocal assignments trickle out due to nodeLocalityDelay. This can have > significant impact on things like CombineFileInputFormat which targets very > specific nodes in its split calculations. > I'm not sure when YARN-4189 will become reality so I thought a simple interim > patch might make sense. The basic idea is simple: > 1) Separate delays for rackLocal, and OffSwitch (today there is only 1) > 2) When we're getting rackLocal assignments, subsequent rackLocal assignments > should not be delayed > Patch will be uploaded shortly. No big deal if the consensus is to go > straight to YARN-4189. -- This message was sent by Atlassian JIRA (v6.3.4#6332)