My theory is that it takes both a certain amount of pressure to create those tools, a certain amount of expertise and a certain amount of tooling available from the language. Due to being old, Perl has all of these and in Devel::NYTProf has a more than excellent profiler that goes beyond line, into statement level. See for example these profiling runs created with it: https://dl.dropboxusercontent.com/u/10190786/ppi_bench.zip