[AMD] Enable BCG on ROCm + route aiter prefill via MHA during PCG/BCG capture for Kimi-2.5 (#27833)

Co-authored-by: sogalin_codegen <39478626+sogalin@users.noreply.github.com>

test/registered/amd/test_kimi_k25_mxfp4_bcg_mi35x.py

@@ -0,0 +1,179 @@
+"""Kimi-K2.5-MXFP4 aiter breakable CUDA-graph (BCG) capture accuracy test
+(MI35x, PR-CI)
+
+Exercises the AMD breakable (BCG) CUDA-graph prefill capture path on a
+deepseek-family (Kimi-K2.5) aiter model so the code added in this PR actually
+runs in PR CI:
+
+  * runner_backend/breakable_cuda_graph_backend.py
+        the ROCm/HIP hard block is removed -> BCG must capture on AMD.
+  * models/deepseek_common/attention_backend_handler.py (handle_attention_aiter)
+        during BCG capture the aiter prefill is routed through the MHA path
+        (is_in_breakable_cuda_graph()).
+
+These branches are gated and default-off, so the default full-cuda-graph CI
+tests never touch them. This test launches the server with
+``--cuda-graph-backend-prefill breakable`` (the config validated in the PR
+description) and asserts GSM8K accuracy, turning "did the capture succeed and
+stay correct?" into a CI signal.
+
+Validated config (PR): Kimi-K2.5-MXFP4 TP4 MI35x, aiter prefill/decode, fp8 KV,
+--enable-aiter-allreduce-fusion -> GSM8K ~0.93 for BCG.
+"""
+
+import os
+import unittest
+from dataclasses import dataclass, field
+from types import SimpleNamespace
+from typing import Dict, List
+
+import requests
+
+from sglang.srt.utils import kill_process_tree
+from sglang.test.ci.ci_register import register_amd_ci
+from sglang.test.few_shot_gsm8k import run_eval as run_eval_few_shot_gsm8k
+from sglang.test.test_utils import (
+    DEFAULT_URL_FOR_TEST,
+    CustomTestCase,
+    is_in_ci,
+    popen_launch_server,
+    write_github_step_summary,
+)
+
+# PR-CI AMD MI35x suite (same suite as the existing Kimi-K2.5-MXFP4 test), so
+# the PR's changed BCG code path is exercised on every run-ci.
+register_amd_ci(est_time=3600, suite="stage-c-test-large-8-gpu-amd-mi35x")
+
+KIMI_K25_MXFP4_MODEL_PATH = "amd/Kimi-K2.5-MXFP4"
+# Same pinned revision as test_kimi_k25_mxfp4.py: revisions from 94d8c1bd
+# onward quantize shared_experts to MXFP4 so shared-experts fusion works.
+KIMI_K25_MXFP4_REVISION = "419004c8716cf22c929aa15d39b85e09a8a2091a"
+SERVER_LAUNCH_TIMEOUT = 3600
+GSM8K_NUM_QUESTIONS = int(os.environ.get("GSM8K_NUM_QUESTIONS", "1319"))
+ACCURACY_THRESHOLD = 0.92
+
+
+@dataclass
+class CaptureConfig:
+    """A prefill cuda-graph capture backend variant to validate."""
+
+    variant: str
+    # Extra server args that select the prefill capture backend.
+    capture_args: List[str]
+    env_vars: Dict[str, str] = field(default_factory=dict)
+
+
+# Common args mirror the PR's validated launch command (TP4, aiter
+# prefill/decode, fp8 KV, allreduce fusion, 8192 chunked prefill).
+COMMON_ARGS: List[str] = [
+    "--revision",
+    KIMI_K25_MXFP4_REVISION,
+    "--tensor-parallel-size",
+    "4",
+    "--trust-remote-code",
+    "--mem-fraction-static",
+    "0.765",
+    "--disable-radix-cache",
+    "--prefill-attention-backend",
+    "aiter",
+    "--decode-attention-backend",
+    "aiter",
+    "--kv-cache-dtype",
+    "fp8_e4m3",
+    "--max-running-requests",
+    "1024",
+    "--enable-aiter-allreduce-fusion",
+    "--chunked-prefill-size",
+    "8192",
+    "--max-prefill-tokens",
+    "8192",
+    "--model-loader-extra-config",
+    '{"enable_multithread_load": true}',
+]
+
+
+def get_capture_configs() -> List[CaptureConfig]:
+    return [
+        # BCG: breakable prefill capture (the path this PR unblocks on ROCm).
+        CaptureConfig(
+            variant="bcg",
+            capture_args=[
+                "--cuda-graph-backend-prefill",
+                "breakable",
+                "--cuda-graph-backend-decode",
+                "full",
+            ],
+        ),
+    ]
+
+
+class TestKimiK25MXFP4BcgMI35x(CustomTestCase):
+    """Validate aiter BCG prefill capture accuracy on MI35x."""
+
+    @classmethod
+    def setUpClass(cls):
+        cls.model = KIMI_K25_MXFP4_MODEL_PATH
+        cls.base_url = DEFAULT_URL_FOR_TEST
+        cls.configs = get_capture_configs()
+
+    def _run_variant(self, config: CaptureConfig) -> float:
+        env = os.environ.copy()
+        env["SGLANG_AITER_MLA_PERSIST"] = "1"
+        for key, value in config.env_vars.items():
+            env[key] = value
+
+        other_args = list(COMMON_ARGS) + list(config.capture_args)
+        process = popen_launch_server(
+            self.model,
+            self.base_url,
+            timeout=SERVER_LAUNCH_TIMEOUT,
+            other_args=other_args,
+            env=env,
+        )
+        try:
+            requests.get(self.base_url + "/flush_cache")
+            args = SimpleNamespace(
+                num_shots=8,
+                data_path=None,
+                num_questions=GSM8K_NUM_QUESTIONS,
+                parallel=GSM8K_NUM_QUESTIONS,
+                max_new_tokens=512,
+                host="http://127.0.0.1",
+                port=int(self.base_url.split(":")[-1]),
+            )
+            metrics = run_eval_few_shot_gsm8k(args)
+            print(f"[{config.variant}] {metrics=}")
+            return metrics["accuracy"]
+        finally:
+            kill_process_tree(process.pid)
+
+    def test_bcg_gsm8k(self):
+        summary = "### Kimi-K2.5-MXFP4 aiter BCG capture (MI35x, TP4)\n\n"
+        summary += "| Capture backend | Accuracy | Threshold | Status |\n"
+        summary += "| --------------- | -------- | --------- | ------ |\n"
+
+        failures = []
+        for config in self.configs:
+            with self.subTest(variant=config.variant):
+                acc = self._run_variant(config)
+                passed = acc >= ACCURACY_THRESHOLD
+                status = "PASS" if passed else "FAIL"
+                summary += (
+                    f"| {config.variant} | {acc:.3f} | "
+                    f"{ACCURACY_THRESHOLD} | {status} |\n"
+                )
+                if not passed:
+                    failures.append((config.variant, acc))
+
+        if is_in_ci():
+            write_github_step_summary(summary)
+
+        self.assertEqual(
+            failures,
+            [],
+            f"BCG accuracy below {ACCURACY_THRESHOLD}: {failures}",
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()