bitbake (openembedded and Yocto) does not use timestamps, but hashes all inputs. Well, it's a bit different scope. It builds packages and each package use make

bitbake (openembedded and Yocto) does not use timestamps, but hashes all inputs. Well, it's a bit different scope. It builds packages and each package use make (or some replacement depending on package maintainer's choice) internally. So the number of files to checksum is small even so if their size can be big, typically mostly the source tarball of the package.