tereius / lehmerchardev

A kernel module that provides a character device generating pseudorandom numbers using Lehmer generator

LehmerCharDev

Provides a very fast pseudorandom number generator (named after D. H. Lehmer) as a kernel character device. This devices writes pseudorandom numbers at comparable speeds to /dev/zero and can be used for I/O filesystem benchmarks. Please make sure that you never use this device for cryptographic purposes!

To give you an idea of the transfer rates I ran some tests with dd tool:

dd bs=	/dev/lehmer	/dev/zero
1	3.0 MB/s	3.8 MB/s
512	1.5 GB/s	1.8 GB/s
4k	4.9 GB/s	10.4 GB/s

How to install

Besides the essential build infrastructure (gcc, make, binutils) you need CMake and the kernel headers of your current kernel.

To build the kernel module just run:

cmake ./ -G "Unix Makefiles" -B ./build_dir
cmake --build ./build_dir

To install the kernel module and add the character device /dev/lehmer:

cmake --build ./build_dir --target install

If the install command fails with "Required key not available" you probably have to disable Secure Boot in UEFI settings.

How to use

You should be abel to use the device like so:

cat /dev/lehmer

To measure the transfer rates run:

dd if=/dev/lehmer of=/dev/null bs=512 count=10000

How to uninstall

To uninstall the kernel module and character device:

cmake --build ./build_dir --target uninstall