+

xFormers Memory Efficient Attention

+

xFormers Benchmark

+
+
+ +▼ code +▼ output + ▶ uv-logs + | +Cell: benchmark | 40.76s + | + +Raw +
+
+
+
# /// script
+# requires-python = ">=3.10"
+# dependencies = [
+#     "numpy",
+#     "torch",
+#     "kernels-benchmark-tools",
+#     "xformers",
+# ]
+#
+# [tool.uv.sources]
+# kernels-benchmark-tools = { git = "https://github.com/drbh/kernels-benchmark-tools.git", branch = "main" }
+# ///
+import torch
+import sys
+import os
+import kernels_benchmark_tools as kbt
+import xformers.ops as xops
+
+
+def xformers_attention(q, k, v):
+    """xFormers memory efficient attention"""
+    # xFormers expects [batch, seq_len, heads, head_dim]
+    return xops.memory_efficient_attention(q, k, v)
+
+
+kbt.add(
+    "xformers_meff",
+    xformers_attention,
+    tags={"family": "xformers", "backend": "memory_efficient", "compile": "none"},
+)
+
+if __name__ == "__main__":
+    device = "cuda" if torch.cuda.is_available() else "cpu"
+    dtype = "float32" if device == "cpu" else "bfloat16"
+
+    # Flux-like workloads
+    base = 1024 if device == "cuda" else 512
+    flux_sizes = (
+        [128, 256, 320, 384, 448, 512] if device == "cuda" else [64, 128, 192, 256]
+    )
+    heads = 24 if device == "cuda" else 8
+    head_dim = 128 if device == "cuda" else 64
+
+    wl = []
+    for L in flux_sizes:
+        wl.append(
+            {
+                "name": f"flux_L{L}",
+                "batch": 1,
+                "seq_len": base + L,
+                "heads": heads,
+                "head_dim": head_dim,
+                "dtype": dtype,
+                "device": device,
+                "seed": 0,
+            }
+        )
+
+    kbt.run(
+        wl,
+        jsonl="attn.jsonl",
+        reps=5,
+        warmup=2,
+        gen=kbt.attn.gen_qkv,
+        ref=kbt.attn.ref_math,
+        cmp=kbt.attn.cmp_allclose,
+    )
+    kbt.summarize(["attn.jsonl"])
+
+ +
+
+
+
+
impl wl p50(ms) ok +xformers_meff flux_L128 0.45 True +xformers_meff flux_L256 0.47 True +xformers_meff flux_L320 0.60 True +xformers_meff flux_L384 0.60 True +xformers_meff flux_L448 0.64 True +xformers_meff flux_L512 0.65 True +
+
+
▶ UV Install Logs
+ +
+
+

Artifacts:

+attn.jsonl +
+
+
+