This can be a terrible idea, but this is how you do it.
Logon as root. Then try to set your process to a very high priority, thus avoiding the scheduler.
One way is -- Use the nice command as a workaround. Also: in Linux there are ways to create realtime priority classes for processes. To determine the highest realtime priority you can set programmatically, make use of the sched_get_priority_max function. Also be aware: MAX_USER_RT_PRIO is the priority user space should ever run in. Period. See sched.h
If timing is such a big deal you should consider synchronization primitives: mutexes, semaphores, locking.
If your code is running as root you can use the nice() syscall to accomplish priority changes as well.
Note: If your process is having a problem it can bring the whole system to its knees.
Since you do not seem to know about process priority I would suggest that other mechanisms be tried first, before nice(). Meaning: Because you are asking this question, it would appear you may not be experienced enough to do realtime coding.
:cool:
I need to execute a shell script to do the following:
cat a file
run two back ground processes using the first two values from the file
wait till those background processes finish
run two more background processes using the next two values from the file
wait till those background... (1 Reply)
o
hola..
Tengo un script que se ejecuta bajo una tarea del CronJOb del unix, tengo la version 11 de unix, mi script tiene un ciclo que lee unos archivos .txt luego cada uno de esos archivos debe pasar por un procedimiento almacenado el cual lo tengo almacenado en mi base de datos oracle 10g,... (4 Replies)
Hi,
I am trying to run a simple UNIX command after i successfully executed SFTP command as shown below.
-----------------------------------------
echo 'Step-1'
sftp -vvv -b path
exit
echo 'Step-2'
------------------------------------------
In above script it executes from the 1st... (3 Replies)
Hello all,
I would be happy if any one could help me with a shell script that would determine all the processes running on a Unix server and post a mail if any of the process is not running or aborted.
Thanks in advance
Regards,
pradeep kulkarni.
:mad: (13 Replies)
Hi Experts, we do have a shell script for Unix Solaris, which will kill all the process manullay, it used to work in my previous env, but now it is throwing this error.. could some one please help me to resolve it
This is how we execute the script (and this is the requirement) ... (2 Replies)
Hi,
I was Googling to get info "How OS loads process into its memory to execute?" i mean when i execute ./<exename> , How OS exectes it?
It will be better if i tell my intention,
In my $LOGNAME saveral process are running, among all of these two process are my target process. Basically I... (1 Reply)
get email notification from from system when a process from XXXX user takes longer than 15 min run.Let me know the time estimation for the same.
hi ,any one please tell me , how to write a script to get email notification from system when a process from as mentioned above a xxxx user takes... (1 Reply)
I need to develop a process/daemon which will constantly monitor a file for new entry and execute a command.
for eg, there is a file /var/log/inotify.log
When a new entry like below gets appeneded to this file, execute the command as follows.
/home/user/public_html/bad.php|CREATE
... (2 Replies)
I am writing a script to kick off a process to gather logs on multiple nodes in parallel using "&". These processes create individual log files. Which I would like to filter and convert in CSV format after they are complete. I am facing following issues:
1. Monitor all Processes parallelly.... (5 Replies)
Team,
I have multiple batchjobs running in VM, if I do ps -ef |grep java or tomcat I am getting multiple process list.
How do I get my exact tomcat process running and that is unique? via shell script? (4 Replies)
Discussion started by: Ghanshyam Ratho
4 Replies
LEARN ABOUT FREEBSD
rtprio
RTPRIO(1) BSD General Commands Manual RTPRIO(1)NAME
rtprio, idprio -- execute, examine or modify a utility's or process's realtime or idletime scheduling priority
SYNOPSIS
[id|rt]prio
[id|rt]prio [-]pid
[id|rt]prio priority command [args]
[id|rt]prio priority -pid
[id|rt]prio -t command [args]
[id|rt]prio -t -pid
DESCRIPTION
The rtprio utility is used for controlling realtime process scheduling.
The idprio utility is used for controlling idletime process scheduling, and can be called with the same options as rtprio.
A process with a realtime priority is not subject to priority degradation, and will only be preempted by another process of equal or higher
realtime priority.
A process with an idle priority will run only when no other process is runnable and then only if its idle priority is equal or greater than
all other runnable idle priority processes.
Both rtprio or idprio when called without arguments will return the realtime priority of the current process.
If rtprio is called with 1 argument, it will return the realtime priority of the process with the specified pid.
If priority is specified, the process or program is run at that realtime priority. If -t is specified, the process or program is run as a
normal (non-realtime) process.
If -pid is specified, the process with the process identifier pid will be modified, else if command is specified, that program is run with
its arguments.
Priority is an integer between 0 and RTP_PRIO_MAX (usually 31). 0 is the highest priority
Pid of 0 means "the current process".
Only root is allowed to set realtime or idle priority for a process. A user may modify the idle priority of their own processes if the
sysctl(8) variable security.bsd.unprivileged_idprio is set to non-zero. Note that this increases the chance that a deadlock can occur if a
process locks a required resource and then does not get to run.
EXIT STATUS
If rtprio execute a command, the exit value is that of the command executed. In all other cases, rtprio exits 0 on success, and 1 for all
other errors.
EXAMPLES
To see which realtime priority the current process is at:
rtprio
To see which realtime priority of process 1423:
rtprio 1423
To run cron(8) at the lowest realtime priority:
rtprio 31 cron
To change the realtime priority of process 1423 to 16:
rtprio 16 -1423
To run tcpdump(1) without realtime priority:
rtprio -t tcpdump
To change the realtime priority of process 1423 to RTP_PRIO_NORMAL (non-realtime/normal priority):
rtprio -t -1423
To make depend while not disturbing other machine usage:
idprio 31 make depend
SEE ALSO nice(1), ps(1), rtprio(2), setpriority(2), nice(3), renice(8)HISTORY
The rtprio utility appeared in FreeBSD 2.0, but is similar to the HP-UX version.
AUTHORS
Henrik Vestergaard Draboel <hvd@terry.ping.dk> is the original author. This implementation in FreeBSD was substantially rewritten by David
Greenman.
CAVEATS
You can lock yourself out of the system by placing a cpu-heavy process in a realtime priority.
BUGS
There is no way to set/view the realtime priority of process 0 (swapper) (see ps(1)).
There is in FreeBSD no way to ensure that a process page is present in memory therefore the process may be stopped for pagein (see
mprotect(2), madvise(2)).
Under FreeBSD system calls are currently never preempted, therefore non-realtime processes can starve realtime processes, or idletime pro-
cesses can starve normal priority processes.
BSD September 29, 2012 BSD