# Multiprocessor Scheduling

## Asymmetric multiprocessing
* Handle all scheduling decision by a single processor
## Symmetric multiprocessing
* Each processor is self-scheduling

## Cache
* 最近被存取的資料會被暫存到processor 的cache

* 如果process移動到另一個processor，cache的資料需要重新產生

* The contents of cache memory must be **invalidated** for the processor being migrate from

* SMP systems
* soft affinity
* hard affinity
## Load balancing
* Keep the workload balanced among all processor

* Push migration
* 平均分配(push/moving)給processor

* Pull migration
* 沒事做的processor會從忙碌的processor抓task過來

* 不論是把一個process push或pull到一另一個processor都會失去cache memory的效益

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##### last edit
> [name=dot] [time=Mon, Jan 6, 2020 3:21 PM]

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