Real Time processes in Linux Post: 302547906

Sponsored Content

Top Forums UNIX for Advanced & Expert Users Real Time processes in Linux Post 302547906 by kumaran_5555 on Wednesday 17th of August 2011 02:01:11 AM

08-17-2011

Registered User

Hi Corona,

following is my code for FIFO and RR. And have started these process from root user to have the CAP_SYS_RESOURCE.

Code:

[hawker@localhost assign_4]$ cat ff_racehorse.c 
#include <stdio.h> 
#include <sched.h>
#include <unistd.h>
#include <sys/types.h>



int main()
{
    
    double a,b,c;
    
    long counter = 1024*1024*512;;    
    
    struct sched_param param;
    param.sched_priority = 99;
    pid_t pid = getpid();
    sched_setscheduler(pid,SCHED_FIFO,&param);
    while(counter--)
    {
        c=a*b;
    }    
    printf("%f %ld\n",c,counter);
}
[hawker@localhost assign_4]$ cat racehorse.c 
#include <stdio.h> 
#include <sched.h>
#include <unistd.h>
#include <sys/types.h>



int main()
{
    
    double a,b,c;
    
    long counter = 1024*1024*512;;    
    
    struct sched_param param;
    param.sched_priority = 99;
    pid_t pid = getpid();
    sched_setscheduler(pid,SCHED_RR,&param);
    while(counter--)
    {
        c=a*b;
    }    
    printf("%f %ld\n",c,counter);
}
[hawker@localhost assign_4]$

Normal process took 55 secs
FIFO took 1 min 25 secs
RR took 2 min 10 secs.

All of them were started one by one.

kumaran_5555

View Public Profile for kumaran_5555

Find all posts by kumaran_5555

6 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

capturing real time

Newbie question: I wrote korn shell script that lets me connect to a cisco switch thru telnet from sun server. I'm wodering if or what command i would use to capture info that is being sent to standard output when the script is running. Putting part of my script below and results. #!/bin/ksh...

2. Solaris

Real time problems

Hi friends, I am new to solaris and looking for a job, when ever i attend interview i get most of the questions on real time problems, every one sak me the same questions what are the problems you face daily.. and what are the types? i know few like, disk extension,swap memory increasing,...

3. Programming

problem with real-time

hello every1, i'm very hope so anyone here have experience with lib rt like aio linux based. In first I've a problem with receiving data from aio_buf, i.e. I have received it, but if the next data size less then pervious I've got a noise from a socket. I've tried to fix it by different ways, but...

4. Shell Programming and Scripting

Shell script to convert epoch time to real time

Dear experts, I have an epoch time input file such as : - 1302451209564 1302483698948 1302485231072 1302490805383 1302519244700 1302492787481 1302505299145 1302506557022 1302532112140 1302501033105 1302511536485 1302512669550 I need the epoch time above to be converted into real...

5. UNIX for Dummies Questions & Answers

Real time processing

Hi Not sure if this can be achieved by unix , but still would like to know if there is any way by which I can do the below given logic cat sam1 > out1 cat sam2 > out2 when either one of this finished the the next file shd be written in that file, meaning cat sam3 >> out1/out2...

6. Shell Programming and Scripting

Converting real time to epoch time

# date +%s -d "Mon Feb 11 02:26:04" 1360567564 # perl -e 'print scalar localtime(1360567564), "\n";' Mon Feb 11 02:26:04 2013 the epoch conversion is working fine. but one of my application needs 13 digit epoch time as input 1359453135154 rather than 10 digit epoch time 1360567564...

LEARN ABOUT CENTOS

sched_getparam

SCHED_SETPARAM(2)					     Linux Programmer's Manual						 SCHED_SETPARAM(2)

NAME

       sched_setparam, sched_getparam - set and get scheduling parameters

SYNOPSIS

       #include <sched.h>

       int sched_setparam(pid_t pid, const struct sched_param *param);

       int sched_getparam(pid_t pid, struct sched_param *param);

       struct sched_param {
	   ...
	   int sched_priority;
	   ...
       };

DESCRIPTION

       sched_setparam()  sets  the scheduling parameters associated with the scheduling policy for the process identified by pid.  If pid is zero,
       then the parameters of the calling process are set.  The interpretation of the argument param depends  on  the  scheduling  policy  of  the
       process identified by pid.  See sched_setscheduler(2) for a description of the scheduling policies supported under Linux.

       sched_getparam() retrieves the scheduling parameters for the process identified by pid.	If pid is zero, then the parameters of the calling
       process are retrieved.

       sched_setparam() checks the validity of param for the scheduling policy of the process.	The value param->sched_priority  must  lie  within
       the range given by sched_get_priority_min(2) and sched_get_priority_max(2).

       For a discussion of the privileges and resource limits related to scheduling priority and policy, see sched_setscheduler(2).

       POSIX systems on which sched_setparam() and sched_getparam() are available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>.

RETURN VALUE

       On success, sched_setparam() and sched_getparam() return 0.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EINVAL The argument param does not make sense for the current scheduling policy.

       EPERM  The calling process does not have appropriate privileges (Linux: does not have the CAP_SYS_NICE capability).

       ESRCH  The process whose ID is pid could not be found.

CONFORMING TO

       POSIX.1-2001.

NOTES

       Scheduling parameters are in fact per-thread attributes on Linux; see sched_setscheduler(2).

SEE ALSO

       getpriority(2), nice(2), sched_get_priority_max(2), sched_get_priority_min(2), sched_getaffinity(2), sched_getscheduler(2),
       sched_setaffinity(2), sched_setscheduler(2), setpriority(2), capabilities(7)

       Programming for the real world - POSIX.4 by Bill O. Gallmeister, O'Reilly & Associates, Inc., ISBN 1-56592-074-0.

COLOPHON

       This page is part of release 3.53 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2013-02-12							 SCHED_SETPARAM(2)