We're using Rake::Pipeline::Middleware to serve a rake-pipeline project with Rack. It seems incredibly slow, like it's rebuilding everything whenever a file has changed.
Are we doing something wrong? Is there something we can do to speed it up?
If you are compressing the files you should put a conditional in your Assetfile to not compress in development. The concat filters are not that slow. The uglify and yui_css filters are and you don't need the compression for dev.