CPU assignment bash script Post: 302422956

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Top Forums Shell Programming and Scripting CPU assignment bash script Post 302422956 by mcky on Wednesday 19th of May 2010 09:50:57 PM

05-19-2010

Registered User

CPU assignment bash script

Hi guys,

I'm basically looking for some help with a bash script I've written. It's purpose is to assign process to individual CPU cores once that process hits 15% CPU usage or more. If it drops below 15%, it's unassigned again (using taskset).

My problem is that I can't think of a way to make the script check if the process is already assigned to an invidividual core, and if so to make it skip the assigning process and remove that core from the array of available cores (there is only enough cores in the array to allow each core to have two processes assigned each [there won't be more than that many processes on the machine so it won't ever go over the limit]). As it currently works, a process might be over 15% and already assigned to one CPU, but if another process' status has changed it could be moved from one CPU to another. I'd like this not to happen, so it doesn't switch processes between CPUs all the time.

Keep in mind I'm pretty basic in my knowledge of this stuff so some parts of the script might be a bit iffy as well. Any suggestions to fix other parts would be appreciated too.

This is what I have so far (for a quad core [you can see it's only for processes with ds_i in them]):

Code:

CPUS=( 1 2 3 0 1 2 3 0 )

PIDS=( `top -b -n 1 | grep ds_i | egrep '[SDR]   ( [0-9]|1[1-4]) ' | sed -e "s/^ *//" -e "s/ .*$//"` )

# Processes with 14% or less usage
for (( e = 0 ; e < ${#PIDS[@]} ; e++ ))
do
taskset -cp 0-3 ${PIDS[$e]}
chrt -o -p 0 ${PIDS[$e]}
done

unset PIDS


PIDS=( `top -b -n 1 | grep ds_i | egrep '[SDR]   ([1][5-9]|[2-9][0-9]) ' | sed -e "s/^ *//" -e "s/ .*$//"` )
# Processes with 15%+ CPU usage
for (( p = 0 ; p < ${#PIDS[@]} ; p++ ))
do
AFF=`taskset -cp ${PIDS[$p]} | sed -e "s/.* current affinity list: //"`

len=`echo $AFF | wc -c`
len=`expr $len - 1`

if [ $len -lt "2" ]
then

        if [ $AFF -lt "4" ]
        then
                for (( e = 0 ; e < ${#CPUS[@]} ; e++ ))
                do

                        if [[ $AFF == ${CPUS[$e]} ]]
                        then
                        unset CPUS[$e] #Remove used CPU from array
                        CPUS=( ${CPUS[*]} )
                        unset PIDS[$p] #Remove PID from array
                        break
                        fi
                done
        fi
fi
done

PIDS=( ${PIDS[*]} )

for (( p = 0 ; p < ${#PIDS[@]} ; p++ ))
do

taskset -cp ${CPUS[0]} ${PIDS[$p]}
chrt -f -p 59 ${PIDS[$p]}
unset CPUS[0]
CPUS=( ${CPUS[*]} )

done

mcky

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LEARN ABOUT XFREE86

libbash

LIBBASH(7)							  libbash Manual							LIBBASH(7)

NAME

     libbash -- A bash shared libraries package.

DESCRIPTION

     libbash  is  a package that enables bash dynamic-like shared libraries. Actually its a tool for managing bash scripts whose functions you may
     want to load and use in scripts of your own.

     It contains a 'dynamic loader' for the shared libraries ( ldbash(1)), a configuration tool (ldbashconfig(8)), and some libraries.

     Using ldbash(1) you are able to load loadable bash libraries, such as getopts(1) and hashstash(1).  A bash shared library that can be  loaded
     using
     ldbash(1) must answer 4 requirments:

     1.     It must be installed in $LIBBASH_PREFIX/lib/bash (default is /usr/lib/bash).

     2.     It must contain a line that begins with '#EXPORT='.  That line will contain (after the '=') a list of functions that the library
	    exports.  I.e. all the function that will be usable after loading that library will be listed in that line.

     3.     It must contain a line that begins with '#REQUIRE='.  That line will contain (after the '=') a list of bash libraries that are
	    required for our library.  I.e. every bash library that is in use in our bash library must be listed there.

     4.     The library must be listed (For more information, see ldbashconfig(8)).

   Basic guidelines for writing library of your own:
     1.     Be aware, that your library will be actually sourced. So, basically, it should contain (i.e define) only functions.

     2.     Try to declare all variables intended for internal use as local.

     3.     Global variables and functions that are intended for internal use (i.e are not defined in '#EXPORT=') should begin with:
		  __<library_name>_
	    For example, internal function myfoosort of hashstash library should be named as
		  __hashstash_myfoosort
	    This helps to avoid conflicts in global name space when using libraries that come from different vendors.

     4.     See html manual for full version of this guide.

AUTHORS

     Hai Zaar <haizaar@haizaar.com>
     Gil Ran <ril@ran4.net>

SEE ALSO

     ldbash(1), ldbashconfig(8), getopts(1), hashstash(1) colors(1) messages(1) urlcoding(1) locks(1)

Linux								       Epoch								     Linux