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The focus on Go compiler speed is kinda weird to me. Other languages sometimes offer flexible tradeoffs to developers. You can build and test C++ programs fair

The focus on Go compiler speed is kinda weird to me. Other languages sometimes offer flexible tradeoffs to developers. You can build and test C++ programs fairly quickly if all the optimizations are disabled, or you can spend a long time building a release binary with optimization, load-testing, profile-guided recompilation, link-time optimization, and post-link optimization. But Go only offers the first thing: a fast compiler with almost no optimizations.

sagichmal 7y ago
The Go compiler contains lots of optimizations, especially considering its age.
- limxto0 7y ago
  Can you share some more details about what those optimizations are? Can you point us to a link?
  - foldr 7y ago
    https://quasilyte.dev/blog/post/go_ssa_rules/ https://quasilyte.dev/blog/post/go_ssa_rules/ is maybe a good starting point.
  - __HYde 7y ago
    You could try compiling with and without `-gcflags '-N -l'` `-N` disables optimization and `-l` disables in-lining. I also found this[0] page which lists some optimizations done by the compiler. [0] https://github.com/golang/go/wiki/CompilerOptimizations https://github.com/golang/go/wiki/CompilerOptimizations edit: You can see what the compiler emits as assembly code with `-gcflags '-S'` so you can compare the optimized vs unoptimized assembly.
- The_rationalist 7y ago
  go is indeed slow, cd benchmarkgames website
bluGill 7y ago
C++ with all optimizations disabled is still slow. g++ takes 2.8 seconds to compile a simple helloworld on my machine - or .14 seconds the second time after caches are warm... Python2 can build and run helloworld in .028 seconds, or .011 once caches are warm. Of course the C++ hello world runs in .002 seconds once build (caches don't seem to make a difference but that might be because it was still in the cache from building)
- dman 7y ago
  What version of gcc? What OS? I am showing ~0.4 seconds on a machine that is 3-4 years old. [PS: I think even 0.4 seconds is too slow]
  - bluGill 7y ago
    4.8.4 Note that only the cached numbers are repeatable. I'm running in a VM, which is likely to be a factor. (IT... the machine exists to run the one VM)
    - dman 7y ago
      I empathize very strongly with you. At a past gig I was in an almost similar position.
- jandrese 7y ago
  C++'s templates (code!) in headers can cause a lot of pain on the compilation front. A simple #include <boost> can add many seconds to your compile.
  - danbolt 7y ago
    Recently at work I was able to use C++ templates to automate a lot of repeated boilerplate code I was responsible for. The reason was to minimize the amount of (error-prone!) rote work that had to be done as the project would continue to scale. It worked out great, but I’ve noticed that the compilation time of translation units that use the templates have been growing linearly with features added. It’s not a lot in the big scheme of things, but it made me wish I could reason more about C++ compile times when I use its various features.

sagichmal 7y ago

The Go compiler contains lots of optimizations, especially considering its age.

limxto0 7y ago
Can you share some more details about what those optimizations are? Can you point us to a link?
- foldr 7y ago
  https://quasilyte.dev/blog/post/go_ssa_rules/ https://quasilyte.dev/blog/post/go_ssa_rules/ is maybe a good starting point.
- __HYde 7y ago
  You could try compiling with and without `-gcflags '-N -l'` `-N` disables optimization and `-l` disables in-lining. I also found this[0] page which lists some optimizations done by the compiler. [0] https://github.com/golang/go/wiki/CompilerOptimizations https://github.com/golang/go/wiki/CompilerOptimizations edit: You can see what the compiler emits as assembly code with `-gcflags '-S'` so you can compare the optimized vs unoptimized assembly.
The_rationalist 7y ago
go is indeed slow, cd benchmarkgames website

bluGill 7y ago

C++ with all optimizations disabled is still slow. g++ takes 2.8 seconds to compile a simple helloworld on my machine - or .14 seconds the second time after caches are warm... Python2 can build and run helloworld in .028 seconds, or .011 once caches are warm. Of course the C++ hello world runs in .002 seconds once build (caches don't seem to make a difference but that might be because it was still in the cache from building)

dman 7y ago
What version of gcc? What OS? I am showing ~0.4 seconds on a machine that is 3-4 years old. [PS: I think even 0.4 seconds is too slow]
- bluGill 7y ago
  4.8.4 Note that only the cached numbers are repeatable. I'm running in a VM, which is likely to be a factor. (IT... the machine exists to run the one VM)
  - dman 7y ago
    I empathize very strongly with you. At a past gig I was in an almost similar position.
jandrese 7y ago
C++'s templates (code!) in headers can cause a lot of pain on the compilation front. A simple #include <boost> can add many seconds to your compile.
- danbolt 7y ago
  Recently at work I was able to use C++ templates to automate a lot of repeated boilerplate code I was responsible for. The reason was to minimize the amount of (error-prone!) rote work that had to be done as the project would continue to scale. It worked out great, but I’ve noticed that the compilation time of translation units that use the templates have been growing linearly with features added. It’s not a lot in the big scheme of things, but it made me wish I could reason more about C++ compile times when I use its various features.