1. Thread 組員：王傳陞、林威丞 黃品舜、李盈賢

2. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Processor affinity  Quantum  thread dispatching  Priority Levels  Windows Scheduling APIs

3. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Processor affinity  Quantum  thread dispatching  Priority Levels  Windows Scheduling APIs

4. Thread-related tools ： Process Explorer

5. Thread-related tools ： Process Explorer (cont.)

6. Download Process Explorer http://www.sysinternals.com Context switch delta ： The number of times that thread began running between the refreshes Process Explorer Thread activity  Context switch delta  CPU percentage

7. Thread-related tools ： Process Explorer (cont.) Thread start address ： Displayed in the form “module!function” address,where module is the name of the.exe or.dll. Note ： Windows threads start at a common process or thread startup wrapper function Problem ： most threads would appear to have started at same address

8. Thread-related tools ： Process Explorer (cont.)

10. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Processor affinity  Quantum  thread dispatching  Priority Levels  Windows Scheduling APIs

11. Why a process is hung Use Process Explorer viewing the thread stack help us determine why a process is hung. Example ： Show that PowerPoint of thread stack.

12. Why a process is hung (cont.)

15. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Processor affinity  Quantum  thread dispatching  Priority Levels  Windows Scheduling APIs

16. Viewing Ready Threads In the WinDbg  kd> !ready 1

17. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Processor affinity  Quantum  thread dispatching  Priority Levels  Windows Scheduling APIs

18. Processor affinity the highest-priority runnable (ready) thread always runs, with the caveat that the thread chosen to run might be limited by the processors, a phenomenon called processor affinity.

19. Processor affinity [wiki] (cont.) [wiki] Example ： Involves two processor-intensive tasks (A & B) having affinity to one processor while another processor lies unused.

20. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Windows Scheduling APIs  Processor affinity  Quantum  thread dispatching  Priority Levels

21. Quantum It run for an amount of time called a quantum Quantum values can vary  System configuration settings  Foreground/background status of the process  Use of the job object to alter the quantum A thread might not complete its quantum  Preemptive scheduler

22. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Windows Scheduling APIs  Processor affinity  Quantum  Thread dispatching  Priority Levels

23. Thread dispatching Events might require thread dispatching  A thread become ready to execute  A thread leaves the running state  A thread’s priority changes  A thread’s processor affinity changes Note: Windows schedule at the thread granularity  Example ： If process A has 10 runnable threads, process B has 2 runnable threads, and all 12 threads are at the same priority. Threads would receive one-twelfth of CPU time Windows wouldn’t give 50% CPU to process A and 50% CPU to process B.

24. Thread dispatching (cont.)

25. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Processor affinity  Quantum  thread dispatching  Priority Levels  Windows Scheduling APIs

26. Priority Levels

27. Thread priority levels are assigned form two different perspectives:  Windows API ： First organizes processes  Windows kernel ： Set relative priority of the individual threads within those processes Priority class  Real-time  High  Above Normal  Normal  Below Normal  Idle

28. Priority Levels (cont.)

29. Process has only one priority values  Current priority Thread has two priority values  Current priority  Base priority

30. Priority Levels (cont.) priority boosting  in the dynamic range (1 through 15) for brief periods.  Windows never adjusts the priority of threads in the real-time range (16 through 31), so they always have the same base and current priority.

31. Priority Levels (cont.) A thread’s initial bas priority is inherited from the process base priority A process inherits its base priority from the process that created it.  CreateProcess function  Command-line START command Changed process priority  SetPriorityClass  Various tools that expose that function Task Manager Process Explorer

32. Priority Levels (cont.) Process base priority  Default to the value at middle of each process priority range(24,13,10,8,6,4)  Some Windows system processes have a bas process priority slightly higer than the default for the Normal class(8) Session Manager, service controller, local security authentication server  Use an internal system call (NtSetInformationProcess) to set process base priority

33. Outline Examining Thread Activity  Thread-related tools ： Process Explorer  Why a process is hung  Viewing Ready Threads Thread Scheduling  Processor affinity  Quantum  thread dispatching  Priority Levels  Windows Scheduling APIs

34. Windows Scheduling APIs Scheduling-Related APIs and Their Functions APIFunction SuspendSuspend/ResumeThreadResumeThreadSuspends or resumes a paused thread from execution. GetGet/SetPriorityClassSetPriorityClassReturns or sets a process's priority class (base priority). GetGet/SetThreadPrioritySetThreadPriorityReturns or sets a thread's priority (relative to its process base priority). GetGet/SetProcessAffinity MaskSetProcessAffinity Mask Returns or sets a process's affinity mask. SetThreadAffinityMaskSets a thread's affinity mask (must be a subset of the process's affinity mask) for a particular set of processors, restricting it to running on those processors.

35. APIFunction SetInformationJobObjectSets attributes for a job; some of the attributes affect scheduling, such as affinity and priority. GetLogicalProcessor Information Returns details about processor hardware configuration (for hyper-threaded [wiki] and NUMA [wiki] systems).[wiki] GetGet/SetThreadPriorityBoostSetThreadPriorityBoostReturns or sets the ability for Windows to boost the priority of a thread temporarily. (This ability applies only to threads in the dynamic range.) SetThreadIdealProcessorEstablishes a preferred processor for a particular thread, but doesn't restrict the thread to that processor. Windows Scheduling APIs (cont.) Scheduling-Related APIs and Their Functions

36. APIFunction GetGet/SetProcess PriorityBoostSetProcess PriorityBoost Returns or sets the default priority boost control state of the current process. (This function is used to set the thread priority boost control state when a thread is created.) SwitchTo Thread Yields execution to another thread (at priority 1 or higher) that is ready to run on the current processor. SleepPuts the current thread into a wait state for a specified time interval (figured in milliseconds [msec]). A zero value relinquishes the rest of the thread's quantum. SleepExCauses the current thread to go into a wait state until either an I/O completion callback is completed, an APC is queued to the thread, or the specified time interval ends. Scheduling-Related APIs and Their Functions Windows Scheduling APIs (cont.)