The _NTO_TRACE_VTHREAD class includes events related to state changes for virtual threads, special objects related to Transparent Distributed Processing (TDP) over Qnet.
The kernel often keeps pointers from different data structures to relevant threads. When those threads are off-node via Qnet, there isn't a local thread object to represent them, so the kernel creates a virtual thread object.
The events for virtual threads are similar to those for normal threads, but virtual threads don't go through the same set of state transitions that normal threads do:
| Event | traceprinter label | IDE label | Emitted when a virtual thread: |
|---|---|---|---|
| _NTO_TRACE_VTHCONDVAR | VTHCONDVAR | VCondvar | Enters the CONDVAR state |
| _NTO_TRACE_VTHCREATE | VTHCREATE | Create VThread | Is created |
| _NTO_TRACE_VTHDEAD | VTHDEAD | VDead | Enters the DEAD state |
| _NTO_TRACE_VTHDESTROY | VTHDESTROY | Destroy VThread | Is destroyed |
| _NTO_TRACE_VTHINTR | VTHINTR | VInterrupt | Enters the INTERRUPT state |
| _NTO_TRACE_VTHJOIN | VTHJOIN | VJoin | Enters the JOIN state |
| _NTO_TRACE_VTHMUTEX | VTHMUTEX | VMutex | Enters the MUTEX state |
| _NTO_TRACE_VTHNANOSLEEP | VTHNANOSLEEP | VNanosleep | Enters the NANOSLEEP state |
| _NTO_TRACE_VTHNET_REPLY | VTHNET_REPLY | VNetReply | Enters the NET_REPLY state |
| _NTO_TRACE_VTHNET_SEND | VTHNET_SEND | VNetSend | Enters the NET_SEND state |
| _NTO_TRACE_VTHREADY | VTHREADY | VReady | Enters the READY state |
| _NTO_TRACE_VTHRECEIVE | VTHRECEIVE | VReceive | Enters the RECEIVE state |
| _NTO_TRACE_VTHREPLY | VTHREPLY | VReply | Enters the REPLY state |
| _NTO_TRACE_VTHRUNNING | VTHRUNNING | VRunning | Enters the RUNNING state |
| _NTO_TRACE_VTHSEM | VTHSEM | VSemaphore | Enters the SEM state |
| _NTO_TRACE_VTHSEND | VTHSEND | VSend | Enters the SEND state |
| _NTO_TRACE_VTHSIGSUSPEND | VTHSIGSUSPEND | VSigSuspend | Enters the SIGSUSPEND state |
| _NTO_TRACE_VTHSIGWAITINFO | VTHSIGWAITINFO | VSigWaitInfo | Enters the SIGWAITINFO state |
| _NTO_TRACE_VTHSTACK | VTHSTACK | VStack | Enters the STACK state |
| _NTO_TRACE_VTHSTOPPED | VTHSTOPPED | VStopped | Enters the STOPPED state |
| _NTO_TRACE_VTHWAITCTX | VTHWAITCTX | VWaitCtx | Enters the WAITCTX state |
| _NTO_TRACE_VTHWAITPAGE | VTHWAITPAGE | VWaitPage | Enters the WAITPAGE state |
| _NTO_TRACE_VTHWAITTHREAD | VTHWAITTHREAD | VWaitThread | Enters the WAITTHREAD state |