.PQ - Display Scheduler Queue Information

Display scheduler thread queue information for all (active) threads.

Syntax:

────.PQ ──────────────────────┬──────────┬────────────────────
                                ├── #    ──┤
                                ├── *    ──┤
                                └── slot ──┘

Parameters:

slot

Display queue status for thread slot slot.

The following short-hand may be used for the slot number:

• The current (last) thread the dispatcher gave control to. This value is taken from the word a global label:

       _TaskNumber
  

  
  
• The debugger default thread slot. This defaults to the current slot unless overridden by the .S command.

  If no slot number is given then all thread slots are displayed in slot number order.

Results & Notes:

The .PQ command locates each thread's TCB from the thread slot table, the linear address of which is given by global variable:

_papTCBSlots

or by traversing the process tree using TCBpTCBNext (TCB +0x14), TCBpPTDA (TCB +0x08) and ptda_pTCBHead (PTDA + 0x20) fields.

Output from the .PQ command appears in tabular form as follows:

 Slot  QSt Pri  pTCB     PriNextQ PriPrevQ PriHigh  PriLow   PriNext  PriPrev
 0001  blk 0100 ffe3c61c
 0002  blk 0200 7b9c8020
 0003  blk 0200 7b9c81d8
 0004  blk 081f 7b9c8390
 0005  blk 0800 7b9c8548
 0006  blk 0800 7b9c8700 7b9cb3b0 7b9c9830
 0008  blk 0500 7b9c8a70
 000a  blk 0800 7b9c8de0
*000b  blk 0800 7b9c8f98 7b9ca960 7b9ca960
 000c# blk 0800 7b9c9150 7b9cab18 7b9cab18

Each of the fields has the following meaning:

slot

The unique (hexadecimal) index in to the thread slot table of all threads.

This value may be flagged with:

• to the left to signify the current (or last) dispatched thread.
  
• to the right to signify the Kernel Debugger default thread slot.

  Slot may be found in the TCBNumber (TCB + 0x2) field of the TCB

QSt
The thread's descending or current scheduler state taken from the TCBQState (TCB +0x160) field.

Except when a state transition is progress this is the same as the desired state of the thread (see Sta field of the .P command.)

The following states are possible:

┌────┬────────────────┬────────────────────┬──────────────────────────────┐
│Abrv│Qst             │TCBQState Value     │Description                   │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│--- │STATE_VOID      │0                   │Uninitialized or Dead thread  │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│rdy │STATE_READY     │1                   │Thread ready to run           │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│blk │STATE_BLOCKED   │2                   │Blocked on a Block Id         │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│sus │STATE_SUSPENDED │3                   │*** Not in Use ***            │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│crt │STATE_CRITSEC   │4                   │Blocked by another CritSec    │
│    │                │                    │thread (after attempting to   │
│    │                │                    │run)                          │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│run │STATE_RUNNING   │5                   │Thread currently running      │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│tsd │STATE_TSD       │7                   │Thread waiting for the TSD    │
│    │                │                    │daemon to page in the TSD.    │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│bst │STATE_READYBOOST│6                   │current state never set to    │
│    │                │                    │this value - see note below.  │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│dly │STATE_DELAYED   │8                   │Delayed TKWakeup (Almost      │
│    │                │                    │Ready)                        │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│frz │STATE_FROZEN    │9                   │Frozen Thread via             │
│    │                │                    │DosSuspendThread,             │
│    │                │                    │DosCreateThread, DosExecPgm or│
│    │                │                    │DosSystemService              │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│gsk │STATE_GETSTACK  │10                  │TSD daemon is waiting for the │
│    │                │                    │page manager to page in a TSD │
├────┼────────────────┼────────────────────┼──────────────────────────────┤
│bad │STATE_BADSTACK  │11                  │TSD failed to page in         │
└────┴────────────────┴────────────────────┴──────────────────────────────┘

Notes:

STATE_READYBOOST is a modified ready state and never becomes the current state, instead a priority boost is applied and the state becomes STATE_READY

See Sta field decription of the .P Command for related information on thread states.

Pri
Thread priority in TCBPriority (TCB +0x168)

This is the current priority calculated by the scheduler based upon priority class (TCBPriClass (TCB +0x164)) priority class level (TCBPrilevel (TCB +0x165)) and priority boosts (TCBPriClassMod (TCB +0x166)). See Pri field description of the .P command for further information.

pTCB
Linear address of the TCB control block that represents the thread.
PriNextQ
The TCB address of the thread at the head of the next priority queue.

PriNextQ is taken from the TCBpTCBPriNextQ (TCB + 0x170) double-word field.

If there are no other linked priority queues then TCBpTCBPriNextQ and TCBpTCBPriPrevQ point to this thread and PriNextQ and PriPrevQ are shown blank.

All TCBs not heading a priority queue have TCBpTCBPriNextQ and TCBpTCBPriPrevQ pointing to themselves.

PriNext and PriPrev is only of relevance to blocked and delayed threads.

PriPrevQ
The TCB address of the thread at the head of the previous priority queue.

PriPrevQ is taken from the TCBpTCBPriPrevQ (TCB + 0x174) double-word field.

If there are no other linked priority queues then TCBpTCBPriNextQ and TCBpTCBPriPrevQ point to this thread and PriNextQ and PriPrevQ are shown blank.

All TCBs not heading a priority queue have TCBpTCBPriNextQ and TCBpTCBPriPrevQ pointing to themselves.

PriNext and PriPrev is only of relevance to blocked and delayed threads.

PriHigh
The TCB address of the next higher priority thread within this priority queue.

PriHigh is taken from the TCBpTCBPriHigher (TCB + 0x178) double-word field.

If there are no higher priority threads on this priority queue then TCBpTCBPriHigher points to this thread and PriHigh is shown blank.

PriLow
The TCB address of the next lower priority thread within this priority queue.

PriLow is taken from the TCBpTCBPriLower (TCB + 0x17c) double-word field.

If there are no lower priority threads on this priority queue then TCBpTCBPriLower points to this thread and PriLow is shown blank.

PriNext
The TCB address of the next thread of the same priority within this priority queue.

PriNext is taken from the TCBpTCBPriNext (TCB + 0x180) double-word field.

If there are no other threads of the same priority on this priority queue then TCBpTCBPriNext and TCBpTCBPriPrev point to this thread and PriNext and PriPrev are shown blank.

PriPrev
The TCB address of the previous thread of the same priority within this priority queue.

Priprev is taken from the TCBpTCBPriPrev (TCB + 0x184) double-word field.

If there are no other threads of the same priority on this priority queue then TCBpTCBPriNext and TCBpTCBPriPrev point to this thread and PriNext and PriPrev are shown blank.

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