HP-UX Reference (11i v2 04/09) - 2 System Calls (vol 5)

rtprio(2) rtprio(2)

indicated by pid .

[EPERM] The group access list of the calling process does not contain a group having

PRIV_RTPRIO capability and prio is not RTPRIO_NOCHG,

RTPRIO_RTOFF with a pid of zero.

[ESRCH] No process can be found corresponding to that speciﬁed by pid .

EXAMPLES

The following call to

rtprio() sets the calling process to a real-time priority of 90:

rtprio(0, 90);

WARNINGS

Normally, compute-bound programs should not be run at real-time priorities, because all timesharing

work on the CPU would come to a complete halt.

DEPENDENCIES

Series 800

Because processes executing at real-time priorities get scheduling preference over a system process exe-

cuting at a lower priority, unexpected system behavior can occur after a power failure on systems that

support power-fail recovery. For example, when

init (see init (1M)) receives the powerfail signal

SIGPWR, it normally reloads programmable hardware such as terminal multiplexers. If a higher-priority

real-time process is eligible to run after the power failure, the running of init is delayed. This condition

temporarily prevents terminal input to any process, including real-time shells of higher priority than the

eligible real-time process. To avoid this situation, a real-time process should catch SIGPWR and suspend

itself until init has ﬁnished its powerfail processing.

AUTHOR

rtprio() was developed by HP.