xref: /aosp_15_r20/external/ltp/utils/benchmark/kernbench-0.42/README (revision 49cdfc7efb34551c7342be41a7384b9c40d7cab7)

Kernbench v0.42


What is this?

This is a cpu throughput benchmark originally devised and used by Martin J.
Bligh. It is designed to compare kernels on the same machine, or to compare
hardware. To compare hardware you need to be running the same architecture
machines (eg i386), the same userspace binaries and run kernbench on the same
kernel source tree.

It runs a kernel at various numbers of concurrent jobs: 1/2 number of cpus,
optimal (default is 4xnumber of cpus) and maximal job count. Optionally it can
also run single threaded. It then prints out a number of useful statistics
for the average of each group of runs and logs them to kernbench.log

You need more than 2Gb of ram for this to be a true throughput benchmark or
else you will get swapstorms.

Ideally it should be run in single user mode on a non-journalled filesystem.
To compare results it should always be run in the same kernel tree.


How do I use it?

You need a kernel tree (any 2.6 will do) and the applications 'time', 'awk',
'date' and 'yes' installed. 'time' is different to the builtin time used by
BASH and has more information desired for this benchmark.

Simply cd into the kernel tree directory and type

/path/to/kernbench


Options

kernbench [-n runs] [-o jobs] [-s] [-H] [-O] [-M] [-h] [-v]
n : number of times to perform benchmark (default 5)
o : number of jobs for optimal run (default 4 * cpu)
s : perform single threaded runs (default don't)
H : don't perform half load runs (default do)
O : don't perform optimal load runs (default do)
M : don't perform maximal load runs (default do)
f : fast run
h : print this help
v : print version number


Changelog:
v0.42 Fixed incorrect counting of cpus (thanks Flynn Marquardt)
	Changed -j to at least 4GB ram.

v0.41 Fixed make oldconfig

v0.40 Made all runs use the oldconfig if it exists. Changed to only do one
	warmup run before all the benchmarks. Added logging to kernbench.log
	Cleaned up the code substantially to reuse code where possible.
	Added standard deviation statistics courtesy of Peter Williams

v0.30 Added fast run option which bypasses caching, warmup and tree
	preparation and drops number of runs to 3. Modified half loads to
	detect -j2 and change to -j3. Added syncs. Improved warnings and
	messages.

v0.20 Change to average of runs, add options to choose which runs to perform
	remove single threaded run from defaults, do warmup run, lots more
	sanity checks, drop meaningless runs, add a few warnings, remove fudge
	factor from no. of jobs.

v0.11 First public release


Thanks: M. Bligh for ideas. Others for help with magic incantations to get
	BASH to work.


Con Kolivas <[email protected]>
Mon Jun 18 18:59:24 2007

License:
GPL of course. Read COPYING included in this tarball.