Attempt to estimate cost of exception raise vs return in CircuitPython

raise_vs_return_code.py

# raise_vs_return_code.py -- Attempt to estimate cost of exception raise vs return in CircuitPython
# 14 May 2024 - @todbot

import time
import random
import gc

num_runs = 50000

# functions that do a small amount of something but really nothing
def do_something_return():
    nstr = str(random.random())
    return nstr

def do_something_raise():
    nstr = str(random.random())
    raise Exception(nstr)


print("num_runs:", num_runs)

gc.collect()
m1s = gc.mem_free()
st = time.monotonic()
for i in range(num_runs):
    do_something_return()
t1 = time.monotonic() - st

m1 = m1s - gc.mem_free()
print("return t:", t1, "mem:", m1)

gc.collect()
m2s = gc.mem_free()
st = time.monotonic()
for i in range(num_runs):
    try:
        do_something_raise()
    except Exception:
        pass
t2 = time.monotonic() - st
m2 = m2s - gc.mem_free() 
print(" raise t:", t2, "mem:", m2)

print("delta: %.3f secs, mem: %.3f bytes" % (t2/t1, m2/m1)) 


while True:
    pass

On Adafruit CircuitPython 9.0.3 on 2024-04-04; LOLIN S3 MINI 4MB Flash 2MB PSRAM with ESP32S3, the results are pretty consistently like this:

num_runs: 50000
return t: 6.66699 mem: 13136
 raise t: 8.86987 mem: 19232
delta: 1.330 secs, mem: 1.464 bytes

That is, about 33% longer in time and about 46% more memory. The 33% longer in time is what I see in Python3.12 on MacOS too. (Python3 gc.mem_free() doesn't exist)