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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rbash

RBASH(1)						      General Commands Manual							  RBASH(1)

NAME

       rbash - restricted bash, see bash(1)

RESTRICTED SHELL

       If  bash  is  started with the name rbash, or the -r option is supplied at invocation, the shell becomes restricted.  A restricted shell is
       used to set up an environment more controlled than the standard shell.  It behaves identically to bash with the exception that the  follow-
       ing are disallowed or not performed:

       o      changing directories with cd

       o      setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV

       o      specifying command names containing /

       o      specifying a file name containing a / as an argument to the .  builtin command

       o      specifying a filename containing a slash as an argument to the -p option to the hash builtin command

       o      importing function definitions from the shell environment at startup

       o      parsing the value of SHELLOPTS from the shell environment at startup

       o      redirecting output using the >, >|, <>, >&, &>, and >> redirection operators

       o      using the exec builtin command to replace the shell with another command

       o      adding or deleting builtin commands with the -f and -d options to the enable builtin command

       o      using the enable builtin command to enable disabled shell builtins

       o      specifying the -p option to the command builtin command

       o      turning off restricted mode with set +r or set +o restricted.

       These restrictions are enforced after any startup files are read.

       When a command that is found to be a shell script is executed, rbash turns off any restrictions in the shell spawned to execute the script.

SEE ALSO

       bash(1)

GNU Bash-4.0							    2004 Apr 20 							  RBASH(1)