[Bf-blender-cvs] [b33d83b] master: Attempted fix for T40363: CUDA 30% slowdown in testbuilds compared to 2.70.

[Brecht Van Lommel]

Commit: b33d83bf51e8a7ecbecde4cc8392c3c7767bc87c
Author: Brecht Van Lommel
Date:   Mon May 26 16:48:30 2014 +0200
https://developer.blender.org/rBb33d83bf51e8a7ecbecde4cc8392c3c7767bc87c

Attempted fix for T40363: CUDA 30% slowdown in testbuilds compared to 2.70.

CMake had this --fast-math flag but scons not, makes a big difference on some
files. Slightly slower rendering might still happen though, but it should not
be this much.

===================================================================

M	intern/cycles/kernel/SConscript

===================================================================

diff --git a/intern/cycles/kernel/SConscript b/intern/cycles/kernel/SConscript
index 04e1bad..ef28f7b 100644
--- a/intern/cycles/kernel/SConscript
+++ b/intern/cycles/kernel/SConscript
@@ -74,7 +74,7 @@ if env['WITH_BF_CYCLES_CUDA_BINARIES']:
 
     # nvcc flags
     nvcc_flags = "-m%s" % (bits)
-    nvcc_flags += " --cubin --ptxas-options=\"-v\""
+    nvcc_flags += " --cubin --ptxas-options=\"-v\" --use_fast_math"
     nvcc_flags += " -D__KERNEL_CUDA_VERSION__=%d" % (cuda_version)
     nvcc_flags += " -DCCL_NAMESPACE_BEGIN= -DCCL_NAMESPACE_END= -DNVCC"
     nvcc_flags += " -I \"%s\" -I \"%s\" -I \"%s\" -I \"%s\"" % (util_dir, svm_dir, geom_dir, closure_dir)