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 |
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.
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
To uninstall the kernel module and character device:
cmake --build ./build_dir --target uninstall