kcbench, the Linux kernel compile benchmark, version 0.9.0 is out

From: Thorsten Leemhuis
Date: Tue Jun 23 2020 - 06:26:20 EST


TWIMC: I released version 0.9.0 of kcbench, a simple Linux kernel
compile benchmark. It basically downloads a Linux version (which one
depends on the compiler used), extracts it, creates a configuration
('defconfig' by default), before it compiles a kernel ('vmlinux') in a
temporary directory ('O=/tmp/foo/') while measuring the time it takes to
build. It compiles a few kernels that way using different number of jobs
(make -j #). After each run kcbench prints the time it took and how many
kernels the machine can build per hour at this rate.

This is how it looks:


> [cttest@localhost ~]$ kcbench

> Processor: Intel(R) Core(TM) i5-3350P CPU @ 3.10GHz [4 CPUs]

> Cpufreq; Memory: powersave [intel_pstate]; 7895 MiB

> Linux running: 5.6.2-125.vanilla.knurd.1.fc31.x86_64 [x86_64]

> Compiler: gcc (GCC) 9.3.1 20200317 (Red Hat 9.3.1-1)

> Linux compiled: 4.19.0 [/home/thl/.cache/kcbench/linux-4.19/]

> Config; Environment: defconfig; CCACHE_DISABLE="1"

> Build command: make vmlinux

> Filling caches: This might take a while... Done

> Run 1 (-j 4): 288.16 seconds / 12.49 kernels/hour [P:384%]

> Run 2 (-j 4): 288.19 seconds / 12.49 kernels/hour [P:384%]

> Run 3 (-j 6): 291.01 seconds / 12.37 kernels/hour [P:384%]

> Run 4 (-j 6): 291.28 seconds / 12.36 kernels/hour [P:385%]



You can use the benchmark to compare different machines, just make sure
they use a similar compiler. Kcbench can be useful for stress tests,
too. It's also a good tool to find the optimal number of jobs for
compiling source code, as 'just use all cores' sometimes is not the
fastest setting, as a quick test on an AMD Ryzen Threadripper 3990X (64
cores/128 threads) recently showed:



> [cttest@localhost ~]$ kcbench -s 5.3 -n 1 -m

> Processor: AMD Ryzen Threadripper 3990X 64-Core Processor [128 CPUs]

> Cpufreq; Memory: Unknown; 63736 MByte RAM

> Linux running: 5.6.0-0.rc2.git0.1.vanilla.knurd.2.fc31.x86_64

> Compiler used: gcc (GCC) 9.2.1 20190827 (Red Hat 9.2.1-1)

> Linux compiled: 5.3.0 [/home/cttest/.cache/kcbench/linux-5.3/]

> Config; Environment: defconfig; CCACHE_DISABLE="1"

> Build command: make vmlinux

> Run 1 (-j 128): 260.43 seconds / 13.82 kernels/hour

> Run 2 (-j 136): 262.67 seconds / 13.71 kernels/hour

> Run 3 (-j 64): 215.54 seconds / 16.70 kernels/hour

> Run 4 (-j 72): 215.97 seconds / 16.67 kernels/hour

(this is a quote from the man-page, which has a few more results)

For more general information about kcbench see:

* its project page:
https://gitlab.com/knurd42/kcbench/

* its README:
https://gitlab.com/knurd42/kcbench/-/blob/master/README.md

* the man-page for kcbench, which tries to compile one Linux kernel
really fast by using many jobs:
https://gitlab.com/knurd42/kcbench/-/raw/master/kcbench.man1.md

* the man-page for kcbenchrate (which is new with 0.9.0 [thx arnd for
the suggestion]), which by default compiles one kernel on each CPU using
one job to measure the rate and keep the all cores busy all the time:
https://gitlab.com/knurd42/kcbench/-/raw/master/kcbenchrate.man1.md

* the release page for kcbench 0.9.0, which list all its major
improvements:
https://gitlab.com/knurd42/kcbench/-/releases/v0.9.0


To quickly outline the potential briefly, here is what a
'kcbench --help' will show:

> Usage: kcbench [options]

>

> Compile a Linux kernel and measure the time it takes.

>

> Available options:

> -b, --bypass -- bypass cache fill run and measure immediately

> -d, --detailedresults -- print more detailed results

> -i, --iterations <int> -- number or iterations per job

> -j, --jobs <int> (*) -- number of jobs to use ('make -j #')

> -m, --modconfig -- build using 'allmodconfig vmlinux modules'

> -o, --outputdir <dir> -- compile in <dir>/kcbench/ ('make O=#')

> -q, --quiet -- quiet

> -s, --src (<dir>|<version>) -- take Linux sources from <dir>; if not found

> try ~/.cache/kcbench/linux-<version>/ and

> /usr/share/kcdata/linux-<version>/; if still

> not found download <version> automatically.

> -v, --verbose (*) -- increase verboselevel

>

> --add-make-args <str> -- pass <str> to make call ('make <str> vmlinux')

> --cc <exec> -- use specified target compiler ('CC=#')

> --cross-compile <arch> -- cross compile for <arch>

> --crosscomp-scheme <str> -- naming scheme for cross compiler

> --hostcc <exec> -- use specified host compiler ('HOSTCC=#')

> --infinite -- run endlessly

> --llvm -- sets 'LLVM=1' to use clang and LLVM tools

> --no-download -- never download anything automatically

> --savefailedlogs <dir> -- save log from failed compilations in <dir>

>

> -h, --help -- show this text

> -V, --version -- output program version

>

> (*) -- option can be passed multiple times


Ciao, Thorsten

P.S.: kcbench is written in Bash, as it started quite small and grew a
lot over time. Maybe at this point bash might not be the best choice,
but OTOH it's something that runs nearly everywhere; it also understood
by a lot of people, which makes it easy to adjust to specific needs.