src/throughput.py

"""Throughput of the three evaluators, measured on one idle machine.

Each evaluator runs the same prefix of the self-describing instance and is
timed after a warm-up, so the rates reported in the paper are not those of runs
that shared the processor with each other.
"""
import json
import os
import sys
import time

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))

REPO = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))


def runs_path(name: str) -> str:
    d = os.path.join(REPO, "paper", "runs")
    os.makedirs(d, exist_ok=True)
    return os.path.join(d, name)


def main() -> int:
    import torch
    from selfrep import (M_P, LevEvaluator, NetEvaluator, describe, read_host,
                         run_reference)
    sigma = read_host()
    r_H = describe(sigma)
    out = {}

    t0 = time.perf_counter()
    o, n = run_reference(M_P, r_H, expect=sigma)
    dt = time.perf_counter() - t0
    assert o == sigma
    out["reference"] = {"steps": n, "seconds": dt, "steps_per_second": n / dt}
    print(f"  integer reference: {n:,} steps in {dt:.2f} s "
          f"({n / dt:,.0f} steps/s)", flush=True)

    N = 20000
    for key, what, ev in (
            ("net_cpu", "the netlist of sigma unit by unit, one core",
             lambda: NetEvaluator(sigma, device="cpu")),
            ("net_gpu", "the netlist of sigma unit by unit, GPU",
             lambda: NetEvaluator(sigma, device="cuda", graph=True))):
        G = ev()
        G.run(M_P, r_H, max_steps=200)                   # warm up
        t0 = time.perf_counter()
        G.run(M_P, r_H, max_steps=N, expect=sigma)
        dt = time.perf_counter() - t0
        out[key] = {"steps": N, "seconds": dt, "steps_per_second": N / dt,
                    "units": G.info["units"], "entries": G.info["entries"]}
        print(f"  {what}: {N:,} steps in {dt:.1f} s ({N / dt:,.0f} steps/s)",
              flush=True)

    D = LevEvaluator(sigma, device="cuda", dense=True)
    entries = sum(int(W.numel()) for W in D.W)
    nonzero = sum(int((W != 0).sum()) for W in D.W)
    D.run(M_P, r_H, max_steps=200)
    t0 = time.perf_counter()
    D.run(M_P, r_H, max_steps=N, expect=sigma)
    dt = time.perf_counter() - t0
    rate = N / dt
    out["dense_gpu"] = {"steps": N, "seconds": dt, "steps_per_second": rate,
                        "entries": entries, "nonzero": nonzero,
                        "bytes_per_step": entries * 4,
                        "bandwidth_gbs": rate * entries * 4 / 1e9}
    print(f"  Lev(N_host) dense on the GPU: {N:,} steps in {dt:.1f} s "
          f"({rate:,.0f} steps/s); {entries:,} entries of which {nonzero:,} "
          f"are nonzero, {entries * 4 / 1e6:.0f} MB read per step, "
          f"{rate * entries * 4 / 1e9:.0f} GB/s", flush=True)

    G2 = LevEvaluator(sigma, device="cuda", dense=False, graph=True)
    G2.run(M_P, r_H, max_steps=200)
    t0 = time.perf_counter()
    G2.run(M_P, r_H, max_steps=N, expect=sigma)
    dt = time.perf_counter() - t0
    out["graph_gpu"] = {"steps": N, "seconds": dt, "steps_per_second": N / dt}
    print(f"  the same map from its nonzero entries, captured as a CUDA graph: "
          f"{N:,} steps in {dt:.1f} s ({N / dt:,.0f} steps/s)", flush=True)

    S = LevEvaluator(sigma, device="cpu", dense=False)
    S.run(M_P, r_H, max_steps=200)
    t0 = time.perf_counter()
    S.run(M_P, r_H, max_steps=N, expect=sigma)
    dt = time.perf_counter() - t0
    out["sparse_cpu"] = {"steps": N, "seconds": dt, "steps_per_second": N / dt}
    print(f"  the same map from its nonzero entries on one core: {N:,} steps in "
          f"{dt:.1f} s ({N / dt:,.0f} steps/s)", flush=True)

    json.dump(out, open(runs_path("paper_throughput.json"), "w"), indent=1)
    return 0


if __name__ == "__main__":
    sys.exit(main())