topic Re: rtsched in Operating System - HP-UX

rtsched

Jose_129 — Thu, 20 Nov 2003 13:25:50 GMT

which is the scheduler in hpux 11i

hp>#rtsched -s
usage: rtsched -s scheduler -p priority command [ arguments ]
rtsched [-s scheduler] -p priority -P pid
where scheduler is one of:
SCHED_FIFO
SCHED_RR
SCHED_RR2
SCHED_RTPRIO
SCHED_HPUX
SCHED_NOAGE
If scheduler is SCHED_HPUX, the priority argument is ignored.

Re: rtsched

Jose_129 — Thu, 20 Nov 2003 13:48:22 GMT

Any news?

Help me please

Re: rtsched

Helen French — Thu, 20 Nov 2003 13:53:33 GMT

Are you looking for more information about that command? Then read this:

# man rtsched

The command you gave came back with error because it's expecting another argument at the place of 'scheduler'. Read the man page and give the proper scheduler you want to use:

# rtsched -s scheduler_name .. options ..

Re: rtsched

Jose_129 — Thu, 20 Nov 2003 14:03:35 GMT

I want to know that Scheduler has set the hpux.
For example:
POSIX real-time schedulers: SCHED_FIFO
SCHED_RR
SCHED_RR2

HP-UX real-time scheduler: SCHED_RTPRI

HP-UX timeshare scheduler: SCHED_HPUX
SCHED_NOAGE

Regards,

Re: rtsched

Jeff Schussele — Thu, 20 Nov 2003 14:06:18 GMT

Hi,

rtsched is a command to alter the default priority of a running or starting process.
It is not the scheduler for the OS.

Of those you listed the SCHED_RR/RR2/FIFO will set POSIX realtime priorities.

The others will set HP-UX realtime priorities.

The differences in RR & RR2 are not implemented in HP-UX, but are there for POSIX compliance i.e RR & RR2 are identical. The diff HP-UX ones just differ on how they implement the priority changes and/or priority aging.

One must be very careful with these as realtime priorities set badly/incorrectly can starve all timeshare (normal) processes of CPU time. Rule of thumb is there better be a d@mn good reason why a process needs realtime priority.

HTH,
Jeff

Re: rtsched

Jeff Schussele — Thu, 20 Nov 2003 14:10:41 GMT

Hi (again) Jose,

Well, if all you want to know is IF the process priority is set into the realtime range then run a long ps

ps -efl PID

Then look at the PRI column. Anything 127 or less is HP-UX realtime. Anything -1 to -32 is POSIX realtime & NO that's NOT negative - it's just a dash. You *can't* have negative priorities.

HTH,
Jeff