topic Re: Scheduler hpux in Operating System - HP-UX

Scheduler hpux

Jose_129 — Thu, 20 Nov 2003 11:25:27 GMT

That scheduler hpux 11i install by default in the server and like modifying it.

Regards,

Jose

Re: Scheduler hpux

Mark Grant — Thu, 20 Nov 2003 11:30:36 GMT

Jose,

Do you mean cron?

If so, try "crontab -e" and enter lines like

00 16 1 * * /usr/local/bin/mycommand

which would run mycommand on the first of each month and 16.00 hours.

THe fields are

MIN HOUR DAY MONTH DAYOFWEEK COMMAND

Where "*" means all

Hope that's what you are after.

Re: Scheduler hpux

Tomek Gryszkiewicz — Thu, 20 Nov 2003 11:30:37 GMT

You mean cron?

-Tomek

Re: Scheduler hpux

doug mielke — Thu, 20 Nov 2003 11:31:31 GMT

Jose,
If you mean used schedule for jobs, look at
cron
crontab

If you mean the Unix process scheduler, there is not much modification possible.
You can set time slice, for instance.

(You could in theory create a 'real time' OS by giving the sched proceess a low priority)

Re: Scheduler hpux

Jose_129 — Thu, 20 Nov 2003 11:52:35 GMT

Real time and time Sharing

Re: Scheduler hpux

Jose_129 — Thu, 20 Nov 2003 12:16:38 GMT

Each thread can be scheduled, synchronized, prioritized, and can send
and receive signals. How i do that?

Re: Scheduler hpux

doug mielke — Thu, 20 Nov 2003 15:38:25 GMT

This might help.
In a multi threaded application, threads could each create a process. Brief look at folowing man pages might get you started.

schedule ===> man cron
crontab
signals send to process ===> kill
rcve from process ==> $?
priorities ====> nice
renice

Re: Scheduler hpux

Jeff Schussele — Thu, 20 Nov 2003 16:34:09 GMT

See his earlier thread...

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=266437

Jose - I think I answered your questions in it. All processes started by users start with a default scheduling priority & increase as they wait for CPU time & decrease as they use it & on & on until they complete. You cannot conrol them unless you use the rtsched or rtprio commands. But *again* I will warn you to not do this UNLESS you know exactly what you're doing & the implications thereof.

Rgds,
Jeff

Re: Scheduler hpux

Jeff Schussele — Thu, 20 Nov 2003 16:37:35 GMT

I'll amend that last answer. Priority can be changed in the timeshare range with the nice & renice commands. But these commands cannot move priorities into the realtime range only rtsched & rtprio can do that.

Rgds,
Jeff

Re: Scheduler hpux

Emil Velez — Thu, 20 Nov 2003 21:01:35 GMT

nice and renice adjust the nice value of normal timeshare processes. Via system calls a program can change its priority when created or during execution.

The rtprio command can create a process or adjust the priority of a proces in the range of 1-127

The rtsched can adjust or create a process with a priority of -32 to 0 and can schedule the program so it runs in a timeshare or FIFO mode.

Watch out creating processes with high priorities.

The other answers mentioned threads. They are correct that individual threads not processes have priorities now with HPUX 10.20 and above. With 11.0 individual threads can have different priorities too and the thread library has system calls to adjust their priority.

I hope this helps

Re: Scheduler hpux

Elmar P. Kolkman — Fri, 21 Nov 2003 01:35:47 GMT

One other way would be PRM (Process Resource Manager), which allow you to make program groups with limits on resources (CPU time, memory, etc) to give more priority to processes that need it. You can even move running processes between groups. But I think you need a keyword (==license) for this to be able to use it.