lookbusy 1.4 -- a synthetic load generator for Linux systems

This is lookbusy, a tool for making systems busy. It uses relatively simple techniques to generate CPU activity, memory and disk utilization and traffic.

lookbusy is not a benchmarking tool, or a realistic load simulator. While it attempts to produce load factors which are exhibited by real applications, the exact operations used are not modelled on real applications, and at the low level, the exact hardware operations are not identical.

• Process Structure

One lookbusy process is forked for each load-generation task -- that is, one process per CPU, one for memory usage, and one for each file on disk being used, plus a toplevel parent process. Errors in or termination of any process will trigger a shutdown in all others. It's safe to use ^C from a terminal, or to kill processes remotely.

• CPU Usage Modes

Two CPU usage modes are provided. The first, 'fixed', attempts to keep total CPU utilization at a particular level, using up any balance in idle time between the other processes on the host and the preferred level (if other processes are themselves able to exceed the chosen level, obviously, lookbusy can't fix that situation but will drop its own usage to near zero and wait for load to drop.)

The second mode, 'curve', produces utilization levels which vary over a chosen range, over a given interval. The simplest (and the default) usage is to modulate usage smoothly over the course of a 24-hour period, peaking at local midnight and bottoming out at local noon. Options are provided to adjust all these settings -- see lookbusy(1).

• CPU Concurrency

lookbusy has basic awareness of multiprocessor and multi-logical-CPU systems; it will attempt to keep cumulative system usage at the chosen level by forking multiple instances of itself, one per CPU. CPUs with a nonzero physical-id, such as are found on hyperthreaded i386 CPUs, are ignored when counting. The CPU utilization algorithm uses a tight arithmetic loop, which should be entirely register-based on most CPUs, incurring no memory traffic.

• Portability

As of 1.0, lookbusy claims support only for Linux systems. Most of its implementation is entirely portable to other UNIX systems; memory and disk usage should work as-is. CPU utilization will almost certainly need porting work, as concerns use of the /proc filesystem and handling of SMP.

How to install

download src by git:

git clone https://github.com/flow2000/lookbusy

or:

wget https://github.com/flow2000/lookbusy/archive/refs/heads/master.zip
unzip master.zip

or:

wget https://ghproxy.com/https://github.com/flow2000/lookbusy/archive/refs/heads/master.zip
unzip master.zip

compile and install:

cd lookbusy

chmod a+x configure

./configure

make

make install

General options

-h, --help Commandline help (you're reading it)

-v, --verbose Verbose output (may be repeated)

-q, --quiet Be quiet, produce output on errors only

CPU usage options:

-c, --cpu-util=PCT, Desired utilization of each CPU, in percent (default --cpu-util=RANGE 50%). If 'curve' CPU usage mode is chosen, a range of the form MIN-MAX should be given.

-n, --ncpus=NUM Number of CPUs to keep busy (default: autodetected)

-r, --cpu-mode=MODE Utilization mode ('fixed' or 'curve', see lookbusy(1))

-p, --cpu-curve-peak=TIME Offset of peak utilization within curve period, in seconds (append 'm', 'h', 'd' for other units)

-P, --cpu-curve-period=TIME Duration of utilization curve period, in seconds (append 'm', 'h', 'd' for other units)

eg:

lookbusy -c 50

lookbusy -c 50 -n 2

lookbusy -c 50-80 -r curve

Memory usage options:

-m, --mem-util=SIZE Amount of memory to use (in bytes, followed by KB, MB, or GB for other units; see lookbusy(1))

-M, --mem-sleep=TIME Time to sleep between iterations, in usec (default 1000)

eg:

lookbusy -m 128MB -M 1000

Disk usage options:

-d, --disk-util=SIZE Size of files to use for disk churn (in bytes, followed by KB, MB, GB or TB for other units)

-b, --disk-block-size=SIZE Size of blocks to use for I/O (in bytes, followed by KB, MB or GB)

-D, --disk-sleep=TIME Time to sleep between iterations, in msec (default 100)

-f, --disk-path=PATH Path to a file/directory to use as a buffer (default /tmp); specify multiple times for additional paths

eg:

lookbusy -d 1GB -b 1MB -D 10

Run in the background

if you need run lookbusy in the background, you can use nohup:

nohup lookbusy -c 50 > /dev/null 2>&1 &
nohup lookbusy -c 50 -n 2 > /dev/null 2>&1 &
nohup lookbusy -c 50-80 -r curve > /dev/null 2>&1 &

When you want to turn off lookbusy, if you use a background mount, such as nohup:

ps -ef | grep lookbusy | grep -v grep

kill this progress:

kill -9 <pid>