理解tornado

Benefits and drawbacks

increased speed of single-threaded programs (no necessity to acquire or release locks on all data structures separately), easy

integration of C libraries that usually are not thread-safe,    ease of implementation (having a single GIL is much simpler to

implement than a lock-free interpreter or one using fine-grained locks).

Use of a global interpreter lock in a language effectively limits the amount of parallelism reachable through concurrency of a

single interpreter process with multiple threads. If the process is almost purely made up of interpreted code and does not

make calls outside of the interpreter for long periods of time (which can release the lock on the GIL on that thread while it

processes), there is likely to be very little increase in speed when running the process on a multiprocessor machine. Due to

signaling with a CPU-bound thread, it can cause a significant slowdown, even on single processors.^[2]