NAME | FEATURE SUMMARY | API | ATTRIBUTES
The VTIMER feature is responsible for all functions pertaining to measurement and timing of thread execution. It exports a number of functions which are typically used by higher-level OS (for example, UNIX) subsystems.
VTIMER functions include thread accounting (threadTimes system call) and virtual timeouts (svVirtualTimeoutSet and svVirtualTimeoutCancel calls). A virtual timeout handler is entered as soon as the designated thread(s) has consumed the specified amount of execution time. Virtual timeouts may be set either on individual threads, for support of subsystem-level virtual timers (for example, SVR4 setitimer VIRTUAL and PROF timers), or on entire actors, for support of process CPU limits.
Execution time accounting may be limited to execution within the thread's home actor (internal execution time), or may include cross-actor invocations such as system calls (total execution time).
svThreadVirtualTimeout and svThreadActorTimeout handlers are invoked at thread level, and thus may use any API service, including blocking system calls. Timeout events are delivered to application threads, much like threadAbort. That is, a thread executes a virtual time handler on its own behalf.
The Time Management API is summarized in the following table:
Comment
Cancel an actor's virtual timeout
Set an actor's virtual timeout
Cancel a thread's virtual timeout
Set a thread's virtual timeout
Cancel a virtual timeout
Set a virtual timeout
Get thread execution times
Get virtual time resolution
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
---|---|
Interface Stability | Evolving |
NAME | FEATURE SUMMARY | API | ATTRIBUTES