debug: add logit quality dump in compute_logits (ungated, once)

vllm/patches/deepseek_v4.py

@@ -2184,6 +2184,17 @@ class DeepseekV4ForCausalLM(nn.Module):
         hidden_states: torch.Tensor,
     ) -> torch.Tensor | None:
         logits = self.logits_processor(self.lm_head, hidden_states)
+        if not getattr(self, '_logit_dumped', False):
+            self._logit_dumped = True
+            last = logits[-1].float()
+            top_vals, top_idx = last.topk(10)
+            print(f"[LOGITS] shape={tuple(logits.shape)} "
+                  f"max={last.max().item():.4e} min={last.min().item():.4e} "
+                  f"mean={last.mean().item():.4e} std={last.std().item():.4e} "
+                  f"finite_frac={torch.isfinite(last).float().mean().item():.4f}")
+            print(f"[LOGITS] top10 ids: {top_idx.tolist()}")
+            print(f"[LOGITS] top10 vals: {[f'{v:.3f}' for v in top_vals.tolist()]}")
+            print(f"[LOGITS] gap top1-top10: {(top_vals[0] - top_vals[-1]).item():.3f}")
         return logits
 
     def forward(