Hi, now that google announced that they are using clang for compiling chrome I wanted to give it a try with DT. I was mainly interested to see what the performance impact is for the DT binary when using clang.
I simply edited build.sh like this to use clang: export CC=/usr/bin/clang export CXX=/usr/bin/clang++ INSTALL_PREFIX_DEFAULT="/opt/darktable-clang" Result: Without opencl the clang binary of DT is three(!) times slower than the gcc binary. And with opencl enabled it is two times slower. 19# ./bench-script-clang-vs-gcc.sh 3 runs no opencl run clang 1: 48,421557 [dev_process_export] pixel pipeline processing took 48,120 secs (47,050 CPU) run gcc 1: 16,068927 [dev_process_export] pixel pipeline processing took 15,733 secs (121,951 CPU) run clang 2: 48,346575 [dev_process_export] pixel pipeline processing took 48,054 secs (47,014 CPU) run gcc 2: 16,240577 [dev_process_export] pixel pipeline processing took 15,914 secs (123,015 CPU) run clang 3: 48,445406 [dev_process_export] pixel pipeline processing took 48,151 secs (47,046 CPU) run gcc 3: 16,402528 [dev_process_export] pixel pipeline processing took 16,073 secs (122,371 CPU) #### 3 runs with opencl run clang 1: 17,418728 [dev_process_export] pixel pipeline processing took 14,533 secs (12,262 CPU) run gcc 1: 9,936274 [dev_process_export] pixel pipeline processing took 7,124 secs (17,697 CPU) run clang 2: 14,816236 [dev_process_export] pixel pipeline processing took 14,448 secs (12,028 CPU) run gcc 2: 7,755369 [dev_process_export] pixel pipeline processing took 7,342 secs (17,904 CPU) run clang 3: 14,897759 [dev_process_export] pixel pipeline processing took 14,528 secs (12,253 CPU) run gcc 3: 7,838780 [dev_process_export] pixel pipeline processing took 7,437 secs (17,954 CPU) I assume I am missing some significant compiler options for clang. But dont know what that is. Can somebody help me with that and tell me what I need to do to make the clang binary faster? Thanks Matthias ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
