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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/51929/
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(Updated Sept. 20, 2016, 10:02 p.m.)


Review request for Aurora, Joshua Cohen, Stephan Erb, and Zameer Manji.


Changes
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Stephan's comments.


Repository: aurora


Description
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This is phase 2 of scheduling perf improvement effort started in 
https://reviews.apache.org/r/51759/.

We can now take multiple (configurable) number of task IDs from a given 
`TaskGroup` per scheduling. The idea is to go deeper through the offer queue 
and assign more than one task if possible. This approach delivers substantially 
better MTTA and still ensures fairness across multiple `TaskGroups`. We have 
observed almost linear improvement in MTTA (4x+ with 5 tasks per round), which 
suggest the `max_tasks_per_schedule_attempt` can be set even higher if the 
majority of cluster jobs have large number of instances and/or update batch 
sizes.

As far as a single round perf goes, we can consider the following 2 worst-case 
scenarios:
- master: single task scheduling fails after trying all offers in the queue
- this patch: N tasks launched with the very last N offers in the queue + `(N x 
single_task_launch_latency)`

Assuming that matching N tasks against M offers takes exactly the same time as 
1 task against M offers (as they all share the same `TaskGroup`), the only 
measurable difference comes from the additional `N x 
single_task_launch_latency` overhead. Based on real cluster observations, the 
`single_task_launch_latency` is less than 1% of a single task scheduling 
attempt, which is << than the savings from avoided additional scheduling 
rounds. 

As far as jmh results go, the new approach (batching + multiple tasks per 
round) is only slightly more demanding (~8%). Both results though are MUCH 
higher than the real cluster perf, which just confirms we are not bound by CPU 
time here:

Master:
```
Benchmark                                                                    
Mode  Cnt      Score     Error  Units
SchedulingBenchmarks.InsufficientResourcesSchedulingBenchmark.runBenchmark  
thrpt   10  17126.183 ± 488.425  ops/s
```

This patch:
```
Benchmark                                                                    
Mode  Cnt      Score     Error  Units
SchedulingBenchmarks.InsufficientResourcesSchedulingBenchmark.runBenchmark  
thrpt   10  15838.051 ± 187.890  ops/s
```


Diffs (updated)
-----

  src/jmh/java/org/apache/aurora/benchmark/SchedulingBenchmarks.java 
6f1cbfbc4510a037cffc95fee54f62f463d2b534 
  src/main/java/org/apache/aurora/scheduler/filter/AttributeAggregate.java 
87b9e1928ab2d44668df1123f32ffdc4197c0c70 
  src/main/java/org/apache/aurora/scheduler/scheduling/SchedulingModule.java 
664bc6cf964ede2473a4463e58bcdbcb65bc7413 
  src/main/java/org/apache/aurora/scheduler/scheduling/TaskGroup.java 
5d319557057e27fd5fc6d3e553e9ca9139399c50 
  src/main/java/org/apache/aurora/scheduler/scheduling/TaskGroups.java 
d390c07522d22e43d79ce4370985f3643ef021ca 
  src/main/java/org/apache/aurora/scheduler/scheduling/TaskScheduler.java 
207d38d1ddfd373892602218a98c1daaf4a1325f 
  src/main/java/org/apache/aurora/scheduler/state/TaskAssigner.java 
7f7b4358ef05c0f0d0e14daac1a5c25488467dc9 
  
src/test/java/org/apache/aurora/scheduler/events/NotifyingSchedulingFilterTest.java
 ece476b918e6f2c128039e561eea23a94d8ed396 
  src/test/java/org/apache/aurora/scheduler/filter/AttributeAggregateTest.java 
209f9298a1d55207b9b41159f2ab366f92c1eb70 
  
src/test/java/org/apache/aurora/scheduler/filter/SchedulingFilterImplTest.java 
0cf23df9f373c0d9b27e55a12adefd5f5fd81ba5 
  src/test/java/org/apache/aurora/scheduler/http/AbstractJettyTest.java 
c1c3eca4a6e6c88dab6b1c69fae3e2f290b58039 
  
src/test/java/org/apache/aurora/scheduler/preemptor/PreemptionVictimFilterTest.java
 ee5c6528af89cc62a35fdb314358c489556d8131 
  src/test/java/org/apache/aurora/scheduler/preemptor/PreemptorImplTest.java 
98048fabc00f233925b6cca015c2525980556e2b 
  src/test/java/org/apache/aurora/scheduler/preemptor/PreemptorModuleTest.java 
2c3e5f32c774be07a5fa28c8bcf3b9a5d88059a1 
  src/test/java/org/apache/aurora/scheduler/scheduling/TaskGroupsTest.java 
88729626de5fa87b45472792c59cc0ff1ade3e93 
  
src/test/java/org/apache/aurora/scheduler/scheduling/TaskSchedulerImplTest.java 
a4e87d2216401f344dca64d69b945de7bcf8159a 
  src/test/java/org/apache/aurora/scheduler/state/TaskAssignerImplTest.java 
b4d27f69ad5d4cce03da9f04424dc35d30e8af29 

Diff: https://reviews.apache.org/r/51929/diff/


Testing
-------

All types of testing including deploying to test and production clusters.


Thanks,

Maxim Khutornenko

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