feat: Triton BLOCK_M 可调(triton_block_m,默认64);bench --triton-bm 扫描

突破:triton评测39.92s/69.72(vs chunked 47.84/67.998)。继续调BLOCK_M榨。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

代码/code/infer.py

@@ -106,7 +106,7 @@ def _triton_varlen_attn(q, k, v, meta):
     """q,k,v: [1, H, S, Dh]（contiguous）。meta=(cu, blk_seq, blk_inseq, total_blocks)。返回 [1,H,S,Dh]。"""
     _, H, S, Dh = q.shape
     cu, blk_seq, blk_inseq, total_blocks = meta
-    BLOCK_M = 64
+    BLOCK_M = CONFIG.get("triton_block_m", 64)
     out = torch.empty_like(q)
     qc = q.contiguous(); kc = k.contiguous(); vc = v.contiguous(); out = out.contiguous()
     stride_h, stride_s, stride_d = S * Dh, Dh, 1
@@ -136,6 +136,7 @@ CONFIG = {
     # sdpa 是评测端验证最快(89.96s/58.86)。flex/compile/小batch/varlen 在评测端都更差。
     # attn: "chunked"(按用户分块SDPA,降O(S²),本地14.25->7.92s) / "sdpa"(稠密mask) / 其它对照
     "attn": "triton",         # Triton varlen flash(单kernel,消逐块调用/mask构造开销);无triton回退chunked
+    "triton_block_m": 64,     # Triton query 块大小(可调 32/64/128;块大=调用少)
     "chunk_users": 4,         # chunked 回退时用;评测扫描 3/4/8 中 4 最优(47.84s/67.998)
     # 稠密MoE去掉了 model(batch) 内唯一的同步点(MoE循环的.nonzero())。若评测计时不
     # synchronize，去掉同步点可能让被计时的 model(batch) 大幅缩短。本地force-sync看不出，
@@ -835,7 +836,7 @@ class CTRModel(nn.Module):
         user_offsets = batch["user_offsets"]
         attn = _resolve_attn(seq_input.device)
         if attn == "triton":
-            meta = _triton_block_meta(user_offsets, 64, seq_input.device)
+            meta = _triton_block_meta(user_offsets, CONFIG.get("triton_block_m", 64), seq_input.device)
             extension = {"triton_meta": meta}
         elif attn == "chunked":
             extension = {"chunks": self.build_chunks(user_offsets, seq_input.device)}
@@ -1071,7 +1072,7 @@ def load_model(ckpt_path, device='cuda:0'):
             H, Dh = model.seq_encoder.n_heads, model.seq_encoder.head_dim
             dummy_off = torch.tensor([0, 64, 130], device=dev)
             dq = torch.randn(1, H, 130, Dh, device=dev, dtype=torch.float16)
-            meta = _triton_block_meta(dummy_off, 64, dev)
+            meta = _triton_block_meta(dummy_off, CONFIG.get("triton_block_m", 64), dev)
             _triton_varlen_attn(dq, dq, dq, meta)
             torch.cuda.synchronize()
             print("[INFO] triton kernel warmed up")