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**haagch** · 12 February 2016, 06:10 AM

That reminded me to put the ekopath-bin package back in the new AUR.

Looks like they still have work to do:

Code:

$ g++ -O3 -fopenmp smallpt.cpp -o smallpt-gcc
$ pathCC -O3 -fopenmp smallpt.cpp -o smallpt-pathCC
smallpt.cpp:55:48: warning: add explicit braces to avoid dangling else [-Wdangling-else]
  if (++depth>5) if (erand48(Xi)<p) f=f*(1/p); else return obj.e; //R.R.
                                               ^
1 warning generated.
$ ./smallpt-gcc
Rendering (4 spp) 100.00%./smallpt-gcc  12.27s user 0.07s system 665% cpu 1.853 total
$ ./smallpt-pathCC
Rendering (4 spp) 14.08%[1]    18744 segmentation fault (core dumped)  ./smallpt-pathCC

Looks like we are super deep in the stack there when it happens: http://haagch.frickel.club/files/gdb-smallpt-pathCC.txt

As usual in these cases, testing OMP_NUM_THREADS=1 ./smallpt-pathCC is the first thing to do and it indeed runs fine, so it's an openmp issue...

But at least that speed goal is reached:

Code:

$ g++ -march=native -O3 -fopenmp smallpt.cpp -o smallpt-gcc
$ pathCC -march=ivy -O3 -fopenmp smallpt.cpp -o smallpt-pathCC
smallpt.cpp:55:48: warning: add explicit braces to avoid dangling else [-Wdangling-else]
  if (++depth>5) if (erand48(Xi)<p) f=f*(1/p); else return obj.e; //R.R.
                                               ^
1 warning generated.
$ OMP_NUM_THREADS=1 ./smallpt-pathCC
Rendering (4 spp) 100.00%OMP_NUM_THREADS=1 ./smallpt-pathCC  6.35s user 0.04s system 99% cpu 6.417 total
$ OMP_NUM_THREADS=1 ./smallpt-gcc
Rendering (4 spp) 100.00%OMP_NUM_THREADS=1 ./smallpt-gcc  7.79s user 0.06s system 99% cpu 7.874 total

By the way: What happened to path64? The github repository is gone and openhub says it didn't receive any commits for over three years.

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