import gc
import sys
import os
import concurrent.futures

def get_rss_mb():
    with open("/proc/self/statm") as f:
        return int(f.read().split()[1]) * os.sysconf("SC_PAGE_SIZE") / (1024 * 1024)

def work(_):
    return [bytearray(64) for _ in range(4000)]


NUM_ITERATIONS = int(sys.argv[1]) if len(sys.argv) > 1 else 20

pool = concurrent.futures.ThreadPoolExecutor(max_workers=4)
for i in range(NUM_ITERATIONS):
    futures = [pool.submit(work, j) for j in range(100)]
    results = [f.result() for f in futures]
    del futures, results  # free worker-allocated objects on main thread
    gc.collect()
    gc.collect()
    blocks = sys.getallocatedblocks()
    print(f"iter {i:3d}: RSS={get_rss_mb():7.1f} MB {blocks=}")

pool.shutdown()
print(f"after shutdown: RSS={get_rss_mb():7.1f} MB")