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0 pointsilitirit6y ago0 comments

The numbers are indeed out of date. I re-ran the tests for some of the C and Nim programs using Nim 0.19.4 and gcc 7.3.0 on Windows 10. Here are the results:

  crb-omp      0m22.949s
  crb          0m23.240s
  crb_opt      0m31.404s

  nimrb_pmap   0m8.828s
  nimrb_fn     0m22.988s
  nimrb        0m26.556s

The base C code is faster than base Nim code. The optimised C code is significantly slower than everything else(!?). The Nim program that uses a threadpool is the fastest of these.

I couldn't get the CPP versions to compile. I'll do the Rust programs some other time.

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tom_mellior6y ago

If you are using a current version of your C compiler and can consistently reproduce those numbers just by adding something like -O3, you should probably file a bug report. Optimizers can go wrong and sometimes pessimize things a bit, but an almost 50% slowdown from enabling optimizations would be treated as an important bug to fix. (Though people are saying that significant amounts of time in the benchmark are spent in random number generation and output, so maybe try to find out first if the problem lies in one of those.)

tom_mellior6y ago

Ah, nevermind, (a) even the "non-optimized" C version uses -O3, and (b) the "C" and the "optimized C" programs differ not only in compiler flags but they are actually different source codes. Specifically, the "optimized C" version doesn't use the faster random number generator.

If you fix that, on my machine it's 17.3 seconds for the base C version and 13.4 for the optimized one, i.e., a 22% improvement from turning on the extra optimizations (-march=native and -ffast-math).

And for whatever it's worth, because some people love hating on GCC in favor of Clang, my Clang timings are 19.5 and 16.5 seconds, respectively.

weberc26y ago

It's surprising that the optimized C is slower; it's much faster on my machine. Like 20s (optimized C) vs 1m20s (unoptimized C).

j / k navigate · click thread line to collapse

0 pointsilitirit6y ago0 comments

The numbers are indeed out of date. I re-ran the tests for some of the C and Nim programs using Nim 0.19.4 and gcc 7.3.0 on Windows 10. Here are the results:

  crb-omp      0m22.949s
  crb          0m23.240s
  crb_opt      0m31.404s

  nimrb_pmap   0m8.828s
  nimrb_fn     0m22.988s
  nimrb        0m26.556s

The base C code is faster than base Nim code. The optimised C code is significantly slower than everything else(!?). The Nim program that uses a threadpool is the fastest of these.

I couldn't get the CPP versions to compile. I'll do the Rust programs some other time.

0 comments

tom_mellior6y ago

And for whatever it's worth, because some people love hating on GCC in favor of Clang, my Clang timings are 19.5 and 16.5 seconds, respectively.

weberc26y ago

It's surprising that the optimized C is slower; it's much faster on my machine. Like 20s (optimized C) vs 1m20s (unoptimized C).

j / k navigate · click thread line to collapse