README: Comment on JIT caching

README.md

@@ -261,3 +261,10 @@ docker build -t waifu2x .
 nvidia-docker run -p 8812:8812 waifu2x th web.lua
 nvidia-docker run -v `pwd`/images:/images waifu2x th waifu2x.lua -force_cudnn 1 -m scale -scale 2 -i /images/miku_small.png -o /images/output.png
 ```
+
+Note that running waifu2x in without [JIT caching](https://devblogs.nvidia.com/parallelforall/cuda-pro-tip-understand-fat-binaries-jit-caching/) is very slow, which is what would happen if you use docker.
+For a workaround, you can mount a host volume to the `CUDA_CACHE_PATH`, for instance,
+
+```
+nvidia-docker run -v $PWD/ComputeCache:/root/.nv/ComputeCache waifu2x th waifu2x.lua --help
+```