The Meson Build System
http://mesonbuild.com/
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88 lines
3.8 KiB
88 lines
3.8 KiB
# A simple comparison |
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In this experiment we generated one thousand C files with contents |
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that looked like this. |
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```c |
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#include<stdio.h> |
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#include"header.h" |
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int func23() { return 0; } |
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``` |
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The function number was different in each file. In addition there was |
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a main C file that just called each function in turn. We then |
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generated build system files for *Meson*, *CMake*, *SCons*, *Premake* |
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and *Autotools* that compiled these files into a single executable. |
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With this we measured three different things. The first is |
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configuration time, that is, the time the build system takes to |
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generate necessary build files. This is usually called the *configure |
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step*. The time was measured in seconds. |
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The second thing to measure was the build time. This should be limited |
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by the compiler and in the optimal case should be the same for every |
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build system. Four parallel processes were used in this test. |
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The third thing we measured was the empty build time. This measures |
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how much time the build system takes to check the states of all source |
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files because if any of them could potentially cause a rebuild. |
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Since CMake has two different backends, Make and Ninja, we ran the |
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tests on both of them. All tests were run on a 2011 era Macbook Pro |
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running Ubuntu 13/04. The tests were run multiple times and we always |
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took the fastest time. |
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Here are the results for configuration time. |
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The reason SCons got zero seconds on this test is because you cannot |
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separate configure and build steps. They run as one unit. Autotools is |
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the clear loser of this test as it is over an order of magnitude |
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slower than the second slowest one. This configuration time includes |
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both autogen and configure. All other systems take less than one |
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second to do this setup, which is fast enough for a human being to |
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interpret as instantaneous. |
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Build times are a bit more even. SCons is the slowest, being almost |
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ten seconds slower than the second slowest. Some of it is work from |
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the configure step but it still has the worst performance. Premake is |
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the fastest Make-based build system narrowly beating out Autotools. |
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Both Ninja-based build systems are faster than all non-Ninja ones with |
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Meson being slightly faster. In practice the difference is minimal. |
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The advantages of Ninja can be seen by comparing CMake's times when |
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using Make or Ninja. It is possible to shave off 3.5 seconds (over |
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20%) of the total build time just by changing the backend. The |
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project's CMake configuration files don't need any changes. |
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Empty build times reflect the performance of regular build times. |
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SCons is again the slowest taking over three seconds compared to |
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Meson, which takes only 0.03 seconds, a difference of two orders of |
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magnitude. Even Autotools, the fastest Make-based system, is almost |
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one order of magnitude slower. Ninja holds the top spots just like in |
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the previous test. |
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Conclusions |
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----- |
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Build system performance matters. Even with this extremely simple |
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example we can find differences between various popular build systems. |
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As the project size increases, these differences grow even larger. |
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(The author has witnessed no-op build times of 30 seconds for Make |
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versus less than one second for Ninja when compiling the Clang |
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compiler.) Keeping incremental build times low is one of the major |
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keys of programmer productivity as it allows developers to iterate |
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faster and stay in the creative zone. |
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Original scripts |
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----- |
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Those who want to run these experiments themselves can download the scripts here: |
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* [Generator script](https://raw.githubusercontent.com/wiki/jpakkane/meson/gen_src.py) |
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* [Measurement script](https://raw.githubusercontent.com/wiki/jpakkane/meson/measure.py)
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