HackMD
Threading Issues
Implicit Threading
- thread 由 compiler 和 run-time library 建立和管理
- 常見方法
- Thread pools
- OpenMP
- Grand Central Dispatch
- TBB(Threading Building Blocks)
Thread Pools
- 預先建立一些 thread 等待 work
- 優點
- 預先建立好，速度較快
- 執行 thread 的數量被 pool 的大小限制
OpenMP
- Provides support for parallel programming in shared-memory environment
- Can identify parallel regions which can run in parallel
Grand Central Dispatch
- Apple technology for Mac OS and iOS operating system
- Allow identification of parallel sections
Signals
- 當某事件(event)發生時會產生signal
- signal會被傳送給process
- 兩種處理方式
- default
- user-defined(會覆蓋掉default)
Thread Cancellation
- 在 thread 完成前終止它
- 兩種方法
- Asynchronous cancellation
- 立即中止
- Deferred cancellation
- 一個時間週期到了才會被取消
- Asynchronous cancellation
- 一般預設是 Deferred cancellation
- 若 thread 的 state 是 disabled (不給取消)，則取消請求一直 pending 到 enabled
Scheduler Activation
- 在 M:M 和 Two-level 中，維持適當的 kernel thread 數量，再分配給程式
- LWP (Light Weight Process)
- 一種資料結構，提供虛擬行程的排程
last edit
dotWed, Jan 22, 2020 2:01 PM
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