This needs a nightly rustc! Because flamer is a compiler plugin, it uses unstable APIs, which are not available on stable or beta. It may be possible to extend flamer to allow use with syntex, but this hasn't been tried yet. You should then be able to annotate every item (or even the whole crate) with #[flame] annotations. You can also use #[noflame] annotations to disable instrumentations for subitems of #[flame]d items. Note that this only instruments the annotated methods, it does not print out the results.