Add S3 streaming benchmark

Extend throughput benchmark to measure direct streaming from the public S3 Zarr and record baseline numbers in the dataset card.

README.md

@@ -93,6 +93,6 @@ Then fill in the table below (the script prints a Markdown row you can paste her
 
 | mode | samples/sec | MB/sec | first_batch_sec |
 |---|---:|---:|---:|
-| local | 0.270 | 259.374 | 6.392 |
-| streaming_hf | TODO | TODO | TODO |
+| local | 0.366 | 351.922 | 3.598 |
+| streaming_s3 | 0.109 | 104.646 | 9.505 |
 

bench/throughput_benchmark.py

@@ -44,6 +44,62 @@ def benchmark_local(zarr_path: str, *, n_samples: int = 16, in_days: int = 7, ou
     return BenchResult('local', samples_per_sec, mb_per_sec, first)
 
 
+def benchmark_s3(
+    s3_root: str,
+    *,
+    n_samples: int = 16,
+    in_days: int = 7,
+    out_days: int = 7,
+    seed: int = 0,
+    time_start: str = "2018-01-01",
+    time_end: str = "2019-12-31",
+    lat_min: float = 20.0,
+    lat_max: float = 50.0,
+    lon_min_360: float = 180.0,
+    lon_max_360: float = 240.0,
+) -> BenchResult:
+    """Benchmark streaming reads directly from the public AWS S3 Zarr."""
+    import s3fs
+
+    fs = s3fs.S3FileSystem(anon=True)
+    store = s3fs.S3Map(root=s3_root, s3=fs, check=False)
+    ds = xr.open_zarr(store, consolidated=True, decode_times=True, mask_and_scale=True, chunks={})
+
+    # Convert lon from [-180, 180] to [0, 360) and subset region/time.
+    ds = ds.assign_coords(lon=((ds["lon"] % 360).astype("float32"))).sortby("lon")
+    ds = ds[["analysed_sst"]].sel(
+        time=slice(np.datetime64(time_start), np.datetime64(time_end)),
+        lat=slice(lat_min, lat_max),
+        lon=slice(lon_min_360, lon_max_360),
+    )
+    var = ds["analysed_sst"]
+
+    rng = np.random.RandomState(seed)
+    max_start = int(ds.sizes["time"]) - (in_days + out_days)
+    idxs = rng.randint(0, max_start + 1, size=n_samples)
+
+    t0 = time.time()
+    i0 = int(idxs[0])
+    x0 = np.asarray(var.isel(time=slice(i0, i0 + in_days)).values)
+    y0 = np.asarray(var.isel(time=slice(i0 + in_days, i0 + in_days + out_days)).values)
+    _ = float(x0.mean() + y0.mean())
+    first = time.time() - t0
+
+    t1 = time.time()
+    bytes_read = 0
+    for i in idxs:
+        i = int(i)
+        x = np.asarray(var.isel(time=slice(i, i + in_days)).values)
+        y = np.asarray(var.isel(time=slice(i + in_days, i + in_days + out_days)).values)
+        bytes_read += x.nbytes + y.nbytes
+        _ = float(x.mean() + y.mean())
+
+    dt = time.time() - t1
+    samples_per_sec = float(len(idxs) / max(dt, 1e-9))
+    mb_per_sec = float((bytes_read / (1024 * 1024)) / max(dt, 1e-9))
+    return BenchResult("streaming_s3", samples_per_sec, mb_per_sec, first)
+
+
 def benchmark_hf(repo_id: str, *, n_samples: int = 16, in_days: int = 7, out_days: int = 7, seed: int = 0) -> BenchResult:
     """Benchmark streaming from HF using the hf:// fsspec protocol.
 
@@ -84,6 +140,7 @@ def benchmark_hf(repo_id: str, *, n_samples: int = 16, in_days: int = 7, out_day
 def main() -> None:
     p = argparse.ArgumentParser()
     p.add_argument('--local', help='Path to pacific_sst.zarr')
+    p.add_argument('--s3-root', help='Public S3 Zarr root (e.g. mur-sst/zarr-v1)')
     p.add_argument('--hf', help='HF dataset repo_id, e.g. KokosDev/mur-sst-ml-benchmark')
     p.add_argument('--n-samples', type=int, default=16)
     p.add_argument('--seed', type=int, default=0)
@@ -92,6 +149,8 @@ def main() -> None:
     results = []
     if args.local:
         results.append(benchmark_local(args.local, n_samples=args.n_samples, seed=args.seed))
+    if args.s3_root:
+        results.append(benchmark_s3(args.s3_root, n_samples=args.n_samples, seed=args.seed))
     if args.hf:
         try:
             results.append(benchmark_hf(args.hf, n_samples=args.n_samples, seed=args.seed))
@@ -99,7 +158,7 @@ def main() -> None:
             print('HF streaming benchmark failed:', repr(e))
             print('Tip: install newer huggingface_hub + fsspec with hf:// support')
     if not results:
-        raise SystemExit('Provide --local and/or --hf')
+        raise SystemExit('Provide --local and/or --s3-root and/or --hf')
 
     print('## Throughput benchmark')
     for r in results: