# Linux Kernel Module Cheat

#### 35.2.3. Benchmark builds

The build times are calculated after doing `./configure` and `make source`, which downloads the sources, and basically benchmarks the Internet.

Sample build time at 2c12b21b304178a81c9912817b782ead0286d282: 28 minutes, 15 with full ccache hits. Breakdown: 19% GCC, 13% Linux kernel, 7% uclibc, 6% host-python, 5% host-qemu, 5% host-gdb, 2% host-binutils

Buildroot automatically stores build timestamps as milliseconds since Epoch. Convert to minutes:

    awk -F: 'NR==1{start=$1}; END{print ($1 - start)/(60000.0)}' "$(./getvar buildroot_build_build_dir)/build-time.log"

Or to conveniently do a clean build without affecting your current one:

    ./bench-all -b
    cat ../linux-kernel-module-cheat-regression/*/build-time.log

- Find which Buildroot packages are making the build slow and big

- Benchmark Buildroot build baseline

- Benchmark gem5 build