Merge branch 'master' of github.com:fluentpython/example-code-2e

This commit is contained in:
Luciano Ramalho
2021-09-23 03:07:25 -03:00
3 changed files with 67 additions and 55 deletions

View File

@@ -69,7 +69,7 @@ class Environment(ChainMap[Symbol, Any]):
"Find where key is defined and change the value there." "Find where key is defined and change the value there."
for map in self.maps: for map in self.maps:
if key in map: if key in map:
map[key] = value map[key] = value # type: ignore[index]
return return
raise KeyError(key) raise KeyError(key)
# end::ENV_CLASS[] # end::ENV_CLASS[]

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@@ -33,40 +33,44 @@ def worker(jobs: JobQueue, results: ResultQueue) -> None: # <7>
results.put(PrimeResult(0, False, 0.0)) # <10> results.put(PrimeResult(0, False, 0.0)) # <10>
# end::PRIMES_PROC_TOP[] # end::PRIMES_PROC_TOP[]
# tag::PRIMES_PROC_MIDDLE[]
def start_jobs(workers: int, jobs: JobQueue, results: ResultQueue) -> None:
for n in NUMBERS:
jobs.put(n) # <1>
for _ in range(workers):
proc = Process(target=worker, args=(jobs, results)) # <2>
proc.start() # <3>
jobs.put(0) # <4>
def report(workers: int, results: ResultQueue) -> int:
checked = 0
workers_done = 0
while workers_done < workers:
n, prime, elapsed = results.get()
if n == 0:
workers_done += 1
else:
checked += 1
label = 'P' if prime else ' '
print(f'{n:16} {label} {elapsed:9.6f}s')
return checked
# end::PRIMES_PROC_MIDDLE[]
# tag::PRIMES_PROC_MAIN[] # tag::PRIMES_PROC_MAIN[]
def main() -> None: def main() -> None:
if len(sys.argv) < 2: # <1> if len(sys.argv) < 2:
workers = cpu_count() workers = cpu_count()
else: else:
workers = int(sys.argv[1]) workers = int(sys.argv[1])
print(f'Checking {len(NUMBERS)} numbers with {workers} processes:') print(f'Checking {len(NUMBERS)} numbers with {workers} processes:')
jobs: JobQueue = SimpleQueue() # <2>
results: ResultQueue = SimpleQueue()
t0 = perf_counter() t0 = perf_counter()
jobs: JobQueue = SimpleQueue()
for n in NUMBERS: # <3> results: ResultQueue = SimpleQueue()
jobs.put(n) start_jobs(workers, jobs, results)
checked = report(workers, results)
for _ in range(workers):
proc = Process(target=worker, args=(jobs, results)) # <4>
proc.start() # <5>
jobs.put(0) # <6>
workers_done = 0
checked = 0
while workers_done < workers: # <7>
n, prime, elapsed = results.get() # <8>
if n == 0:
workers_done += 1 # <9>
else:
checked += 1
label = 'P' if prime else ' '
print(f'{n:16} {label} {elapsed:9.6f}s') # <10>
elapsed = perf_counter() - t0 elapsed = perf_counter() - t0
print(f'{checked} checks in {elapsed:.2f}s') # <11> print(f'{checked} checks in {elapsed:.2f}s')
if __name__ == '__main__': if __name__ == '__main__':
main() main()

View File

@@ -1,8 +1,8 @@
#!/usr/bin/env python3 #!/usr/bin/env python3
""" """
threads.py: shows that Python threads are slower than threads.py: shows that Python threads are slower
sequential code for CPU-intensive work. than sequential code for CPU-intensive work.
""" """
import os import os
@@ -14,52 +14,60 @@ from threading import Thread
from primes import is_prime, NUMBERS from primes import is_prime, NUMBERS
class PrimeResult(NamedTuple): # <3> class PrimeResult(NamedTuple):
n: int n: int
prime: bool prime: bool
elapsed: float elapsed: float
JobQueue = SimpleQueue[int] JobQueue = SimpleQueue[int] # <4>
ResultQueue = SimpleQueue[PrimeResult] ResultQueue = SimpleQueue[PrimeResult] # <5>
def check(n: int) -> PrimeResult: def check(n: int) -> PrimeResult: # <6>
t0 = perf_counter() t0 = perf_counter()
res = is_prime(n) res = is_prime(n)
return PrimeResult(n, res, perf_counter() - t0) return PrimeResult(n, res, perf_counter() - t0)
def worker(jobs: JobQueue, results: ResultQueue) -> None: def worker(jobs: JobQueue, results: ResultQueue) -> None: # <7>
while n := jobs.get(): while n := jobs.get(): # <8>
results.put(check(n)) results.put(check(n)) # <9>
results.put(PrimeResult(0, False, 0.0))
def main() -> None:
if len(sys.argv) < 2: # <1>
workers = os.cpu_count() or 1 # make mypy happy
else:
workers = int(sys.argv[1])
print(f'Checking {len(NUMBERS)} numbers with {workers} threads:')
jobs: JobQueue = SimpleQueue() # <2>
results: ResultQueue = SimpleQueue()
t0 = perf_counter()
def start_jobs(workers: int, jobs: JobQueue, results: ResultQueue) -> None:
for n in NUMBERS: # <3> for n in NUMBERS: # <3>
jobs.put(n) jobs.put(n)
for _ in range(workers): for _ in range(workers):
proc = Thread(target=worker, args=(jobs, results)) # <4> proc = Thread(target=worker, args=(jobs, results)) # <4>
proc.start() # <5> proc.start() # <5>
jobs.put(0) # <6> jobs.put(0) # <6>
while True: def report(workers: int, results: ResultQueue) -> int:
n, prime, elapsed = results.get() # <7> checked = 0
label = 'P' if prime else ' ' workers_done = 0
print(f'{n:16} {label} {elapsed:9.6f}s') while workers_done < workers:
if jobs.empty(): # <8> n, prime, elapsed = results.get()
break if n == 0:
workers_done += 1
else:
checked += 1
label = 'P' if prime else ' '
print(f'{n:16} {label} {elapsed:9.6f}s')
return checked
def main() -> None:
if len(sys.argv) < 2:
workers = os.cpu_count()
else:
workers = int(sys.argv[1])
print(f'Checking {len(NUMBERS)} numbers with {workers} threads:')
t0 = perf_counter()
jobs: JobQueue = SimpleQueue()
results: ResultQueue = SimpleQueue()
start_jobs(workers, jobs, results)
checked = report(workers, results)
elapsed = perf_counter() - t0 elapsed = perf_counter() - t0
print(f'Total time: {elapsed:.2f}s') print(f'{checked} checks in {elapsed:.2f}s')
if __name__ == '__main__': if __name__ == '__main__':
main() main()