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Kubernetes Submit Queue 795b7da8b0 Merge pull request #65714 from resouer/fix-63784

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Re-design equivalence class cache to two level cache

**What this PR does / why we need it**:

The current ecache introduced a global lock across all the nodes, and this patch tried to assign ecache per node to eliminate that global lock. The improvement of scheduling performance and throughput are both significant.

**CPU Profile Result** 

Machine: 32-core 60GB GCE VM

1k nodes 10k pods bench test (we've highlighted the critical function):

1. Current default scheduler with ecache enabled:
![equivlance class cache bench test 001](https://user-images.githubusercontent.com/1701782/42196992-51b0a32a-7eb3-11e8-89ee-f13383091a00.jpeg)
2. Current default scheduler with ecache disabled:
![equivlance class cache bench test 002](https://user-images.githubusercontent.com/1701782/42196993-51eb0c68-7eb3-11e8-9326-1a7762072863.jpeg)
3. Current default scheduler with this patch and ecache enabled:
![equivlance class cache bench test 003](https://user-images.githubusercontent.com/1701782/42196994-52280ed8-7eb3-11e8-8100-690e2af2cf2f.jpeg)

**Throughput Test Result** 

1k nodes 3k pods `scheduler_perf` test: 

Current default scheduler, ecache is disabled:
```bash
Minimal observed throughput for 3k pod test: 200
PASS
ok      k8s.io/kubernetes/test/integration/scheduler_perf    30.091s
```
With this patch, ecache is enabled:
```bash
Minimal observed throughput for 3k pod test: 556
PASS
ok      k8s.io/kubernetes/test/integration/scheduler_perf    11.119s
```

**Design and implementation:**

The idea is: we re-designed ecache into a "two level cache". 

The first level cache holds the global lock across nodes and sync is needed only when node is added or deleted, which is of much lower frequency. 

The second level cache is assigned per node and its lock is restricted to per node level, thus there's no need to bother the global lock during whole predicate process cycle. For more detail, please check [the original discussion](https://github.com/kubernetes/kubernetes/issues/63784#issuecomment-399848349).

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #63784

**Special notes for your reviewer**:

~~Tagged as WIP to make sure this does not break existing code and tests, we can start review after CI is happy.~~

**Release note**:

```release-note
Re-design equivalence class cache to two level cache
```

2018-07-19 16:16:02 -07:00

BUILD

Run hack/update-bazel.sh

2018-06-22 16:22:57 -07:00

cache_comparer_test.go

Merge pull request #63666 from xchapter7x/pkg-scheduler-factory

2018-07-19 02:09:06 -07:00

cache_comparer.go

Move pkg/scheduler/schedulercache -> pkg/scheduler/cache

2018-05-31 22:55:34 +08:00

factory_test.go

Merge pull request #63666 from xchapter7x/pkg-scheduler-factory