[Perf]: Rlease GIL in the core simulation function

[haochengxia]

Here is the PoC.

import libcachesim as lcs
import threading
import time

S3_URI = "s3://cache-datasets/cache_dataset_oracleGeneral/2007_msr/msr_hm_0.oracleGeneral.zst"

def run_heavy_simulation(name):
    # Create a large synthetic trace
    reader = lcs.TraceReader(trace=S3_URI)
    cache = lcs.LRU(cache_size=1024*1024)

    print(f"Thread {name} starting simulation...")
    start = time.time()
    # Call C++ core logic
    lcs.Util.process_trace(cache, reader)
    end = time.time()
    print(f"Thread {name} completed in {end - start:.2f}s")

# --- Experiment start ---
start_total = time.time()

t1 = threading.Thread(target=run_heavy_simulation, args=("A",))
t2 = threading.Thread(target=run_heavy_simulation, args=("B",))

t1.start()
t2.start()

t1.join()
t2.join()

end_total = time.time()
print(f"\nTotal elapsed time: {end_total - start_total:.2f}s")

# Verification:
# If total time ≈ single-thread time -> GIL released successfully (Success)
# If total time ≈ single-thread time * 2 -> GIL still held (Fail)

The output is

[INFO]  05-17-2026 00:16:42 cli_reader_utils.c:213  (tid=123568604841664): detecting trace type: ORACLE_GENERAL_TRACE
Thread A starting simulation...
Thread A completed in 0.45s
[INFO]  05-17-2026 00:16:42 cli_reader_utils.c:213  (tid=123568596448960): detecting trace type: ORACLE_GENERAL_TRACE
Thread B starting simulation...
Thread B completed in 0.42s

Total elapsed time: 0.91s

[haochengxia]

Closed by #60