08-15-2011
Real Time processes in Linux
I was trying to experiment with SCHED_RR and SCHED_FIFO.
I tried benchmarking the SCHED_NORMAL with these two real time priorities.
What I found is strange result. SHED_RR was the slowest then comes SCHED_FIFO and SCHED_NORMAL was the fastest one.
All tests are run in same situation and independently. And these process are only CPU intensive, no IO.
I expect FIFO to run faster because no no content switching. Can anyone help understand this mystery.
6 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
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 Replies)
Discussion started by: wisher115
2 Replies
2. Solaris
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,... (2 Replies)
Discussion started by: kurva
2 Replies
3. Programming
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... (0 Replies)
Discussion started by: quant
0 Replies
4. Shell Programming and Scripting
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... (4 Replies)
Discussion started by: aismann
4 Replies
5. UNIX for Dummies Questions & Answers
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... (2 Replies)
Discussion started by: Sri3001
2 Replies
6. Shell Programming and Scripting
# 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... (3 Replies)
Discussion started by: vivek d r
3 Replies
LEARN ABOUT LINUX
sched_get_priority_max
SCHED_GET_PRIORITY_MAX(2) Linux Programmer's Manual SCHED_GET_PRIORITY_MAX(2)
NAME
sched_get_priority_max, sched_get_priority_min - get static priority range
SYNOPSIS
#include <sched.h>
int sched_get_priority_max(int policy);
int sched_get_priority_min(int policy);
DESCRIPTION
sched_get_priority_max() returns the maximum priority value that can be used with the scheduling algorithm identified by policy.
sched_get_priority_min() returns the minimum priority value that can be used with the scheduling algorithm identified by policy. Supported
policy values are SCHED_FIFO, SCHED_RR, SCHED_OTHER, and SCHED_BATCH. Further details about these policies can be found in sched_setsched-
uler(2).
Processes with numerically higher priority values are scheduled before processes with numerically lower priority values. Thus, the value
returned by sched_get_priority_max() will be greater than the value returned by sched_get_priority_min().
Linux allows the static priority value range 1 to 99 for SCHED_FIFO and SCHED_RR and the priority 0 for SCHED_OTHER and SCHED_BATCH.
Scheduling priority ranges for the various policies are not alterable.
The range of scheduling priorities may vary on other POSIX systems, thus it is a good idea for portable applications to use a virtual pri-
ority range and map it to the interval given by sched_get_priority_max() and sched_get_priority_min(). POSIX.1-2001 requires a spread of
at least 32 between the maximum and the minimum values for SCHED_FIFO and SCHED_RR.
POSIX systems on which sched_get_priority_max() and sched_get_priority_min() are available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>.
RETURN VALUE
On success, sched_get_priority_max() and sched_get_priority_min() return the maximum/minimum priority value for the named scheduling pol-
icy. On error, -1 is returned, and errno is set appropriately.
ERRORS
EINVAL The argument policy does not identify a defined scheduling policy.
CONFORMING TO
POSIX.1-2001.
SEE ALSO
sched_getaffinity(2), sched_getparam(2), sched_getscheduler(2), sched_setaffinity(2), sched_setparam(2), sched_setscheduler(2)
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 3.27 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 2006-03-23 SCHED_GET_PRIORITY_MAX(2)