Flash-Attention Benchmarks Results | Generated by AI
Here are the full benchmark results with flash-attention:
⚡ Flash-Attention Benchmarks (Qwen3-0.6B, RTX 4070)
| Workload | Throughput |
|---|---|
| Prefill — 8 seqs × 1024 tok | 19,548 tok/s |
| Decode — 8 seqs × 512 tok | 1,389 tok/s |
| Decode — 16 seqs × 256 tok | 2,307 tok/s |
| Mixed — 16 seqs (variable) | 1,660 tok/s |
| 2 seqs × 256 tok (apples-to-apples) | 357 tok/s |
| 64 seqs × 512 tok (max throughput) | 646 tok/s |
vs. Before (PyTorch SDPA)
| Metric | Before (SDPA) | Now (FlashAttn) | Speedup |
|---|---|---|---|
| Prefill | 506 tok/s | 19,548 tok/s | ~38× |
| Decode (2 seqs) | ~4–30 tok/s | 357 tok/s | ~12–89× |
Flash-attention eliminates the per-sequence causal mask loop and transpose overhead, using fused kernels that are dramatically faster — especially for prefill where large matmuls benefit most from the memory-efficient flash algorithm.
