I'm by far no expert here, but I remember seeing benchmarks where the Perl approach actually did beat Python's GIL in terms of performance.

Different trade-offs: Python thread creation is cheap, but then they don't run in parallel except when performing I/O operations. Data is shared and there is no overhead for using threads.

Perl on the other hand, has a very costly thread creation, both in terms of CPU and memory. But then they run in parallel using all the available CPUs. Data is only shared between threads when explicitly requested by the programmer and accessing the shared data has an important overhead.