The script loadserver.sh :
[root@foo313 ~]# cat loadserver.sh
#!/bin/sh
# unixfoo.blogspot.com
if [ $1 ]; then
NUM_PROC=$1
else
NUM_PROC=10
fi
for i in `seq 0 $((NUM_PROC-1))`; do
awk ‘BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}’ &
done
echo “PIDS: `pidof awk`”
[root@foo313 ~]#
Before script execution :
[root@foo313 ~]# uptime
09:22:18 up 14 days, 2:07, 3 users, load average: 0.00, 0.02, 0.04
[root@foo313 ~]#
Script execution :
[root@foo313 ~]# ./loadserver.sh 10
PIDS: 11429 11428 11427 11426 11425 11424 11423 11422 11421 11420
[root@foo313 ~]# ps -ef | grep awk
root 11420 1 31 09:22 pts/1 00:00:01 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11421 1 45 09:22 pts/1 00:00:02 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11422 1 32 09:22 pts/1 00:00:01 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11423 1 29 09:22 pts/1 00:00:01 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11424 1 48 09:22 pts/1 00:00:02 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11425 1 45 09:22 pts/1 00:00:02 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11426 1 27 09:22 pts/1 00:00:01 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11427 1 46 09:22 pts/1 00:00:02 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11428 1 28 09:22 pts/1 00:00:01 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11429 1 34 09:22 pts/1 00:00:01 awk BEGIN {for(i=0;i<10000;i++)for(j=0;j<10000;j++);}
root 11450 11351 0 09:22 pts/1 00:00:00 grep awk
Check out the load :
[root@foo313 ~]# uptime
09:22:44 up 14 days, 2:07, 3 users, load average: 4.07, 0.93, 0.34
[root@foo313 ~]#
[root@foo313 ~]# mpstat 1
Linux 2.6.21 (foo313) 11/12/2008
09:24:56 AM CPU %user %nice %system %iowait %irq %soft %idle intr/s
09:24:57 AM all 99.00 0.00 0.75 0.00 0.00 0.25 0.00 678.79
09:24:58 AM all 99.75 0.00 0.00 0.00 0.00 0.25 0.00 149.00
09:24:59 AM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 113.00
09:25:00 AM all 99.50 0.00 0.50 0.00 0.00 0.00 0.00 186.00
[root@foo313 ~]#