The DCMD_PROC_TIDSTATUS command

The DCMD_PROC_TIDSTATUS command returns a structure of type procfs_status, which is equivalent to debug_thread_t:

typedef struct _debug_thread_info {
  pid_t       pid;
  pthread_t   tid;
  uint32_t    flags;
  uint16_t    why;
  uint16_t    what;
  uint64_t    ip;
  uint64_t    sp;
  uint64_t    stkbase;
  uint64_t    tls;
  uint32_t    stksize;
  uint32_t    tid_flags;
  uint8_t     priority;
  uint8_t     real_priority;
  uint8_t     policy;
  uint8_t     state;
  int16_t     syscall;
  uint16_t    last_cpu;
  uint32_t    timeout;
  int32_t     last_chid;
  sigset_t    sig_blocked;
  sigset_t    sig_pending;
  siginfo_t   info;

  // blocking information deleted (see next section)

  uint64_t    start_time;
  uint64_t    sutime;
} debug_thread_t;

More information than you can shake a stick at (224 bytes)! Here are the fields and their meanings:

pid and tid: The process ID and the thread ID.
flags: Flags indicating characteristics of the thread (see <sys/debug.h> and look for the constants beginning with _DEBUG_FLAG_).
why and what: The why indicates why the thread was stopped (see <sys/debug.h> and look for the constants beginning with _DEBUG_WHY_) and the what provides additional information for the why parameter. For _DEBUG_WHY_TERMINATED, the what variable contains the exit code value, for _DEBUG_WHY_SIGNALLED and _DEBUG_WHY_JOBCONTROL, what contains the signal number, and for _DEBUG_WHY_FAULTED, what contains the fault number (see <sys/fault.h> for the values).
ip: The current instruction pointer where this thread is executing.
sp: The current stack pointer for the thread.
stkbase and stksize: The base of the thread's stack, and the stack size.
tls: The Thread Local Storage (TLS) data area. See <sys/storage.h>.
tid_flags: See <sys/neutrino.h> constants beginning with _NTO_TF.
priority and real_priority: The priority indicates thread priority used for scheduling purposes (may be boosted), and the real_priority indicates the actual thread priority (not boosted).
policy: The scheduling policy (e.g. FIFO, Round Robin).
state: The current state of the thread (see <sys/states.h>, e.g., STATE_MUTEX if blocked waiting on a mutex).
syscall: Indicates the last system call that the thread made (see <sys/kercalls.h>).
last_cpu: The last CPU number that the thread ran on (for SMP systems).
timeout: Contains the flags parameter from the last TimerTimeout() call.
last_chid: The last channel ID that this thread MsgReceive()'d on. Used for priority boosting if a client does a MsgSend() and there are no threads in STATE_RECEIVE on the channel.
sig_blocked, sig_pending, and info: These fields all relate to signals—recall that signals have a process aspect as well as a thread aspect. The sig_blocked indicates which signals this thread has blocked. Similarly, sig_pending indicates which signals are pending on this thread. The info member carries the information for a sigwaitinfo() function.
start_time: The time, in nanoseconds since January 1, 1970, that the thread was started. Useful for detecting thread ID reuse.
sutime: Thread's system and user running times (in nanoseconds).