[Feature][TTS] Add Speech API streaming metrics (#6853)

Signed-off-by: XIN GAO <1037396230@qq.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

tests/entrypoints/openai_api/test_serving_speech_stream.py

@@ -48,7 +48,14 @@ def _build_test_app(
         speech_service.forced_aligner_enabled = False
 
         async def mock_generate_pcm_chunks(
-            _generator, _request_id, *, include_sample_rate=False, tts_params=None, collect=None
+            _generator,
+            _request_id,
+            *,
+            request_start_s=None,
+            request_arrival_ts=None,
+            include_sample_rate=False,
+            tts_params=None,
+            collect=None,
         ):
             for chunk in (b"\x01\x02", b"\x03\x04\x05"):
                 yield (chunk, 24000) if include_sample_rate else chunk
@@ -249,6 +256,7 @@ class TestStreamingSpeechWebSocket:
 
     def test_streaming_multiple_binary_frames(self, mocker: MockerFixture):
         captured_requests = []
+        captured_timing = {}
         captured_tts_params = []
 
         speech_service = mocker.MagicMock(spec=OmniOpenAIServingSpeech)
@@ -257,13 +265,27 @@ class TestStreamingSpeechWebSocket:
         speech_service.engine_client.abort = mocker.AsyncMock()
         speech_service.forced_aligner_enabled = False
 
-        async def mock_prepare_speech_generation(request):
+        async def mock_prepare_speech_generation(request, *, arrival_time=None):
             captured_requests.append(request)
+            assert arrival_time is not None
+            captured_timing["prepare_arrival"] = arrival_time
             return "req-stream", object(), {"_qwen3_tts_effective_max_tokens": [192]}
 
         speech_service._prepare_speech_generation = mock_prepare_speech_generation
 
-        async def mock_generate_pcm_chunks(_generator, _request_id, *, include_sample_rate=False, tts_params=None):
+        async def mock_generate_pcm_chunks(
+            _generator,
+            _request_id,
+            *,
+            request_start_s=None,
+            request_arrival_ts=None,
+            include_sample_rate=False,
+            tts_params=None,
+        ):
+            assert request_start_s is not None
+            assert request_arrival_ts is not None
+            captured_timing["chunk_start"] = request_start_s
+            captured_timing["chunk_arrival"] = request_arrival_ts
             captured_tts_params.append(tts_params)
             for chunk in (b"\x01\x02", b"\x03\x04\x05", b"\x06"):
                 yield (chunk, 24000) if include_sample_rate else chunk
@@ -309,6 +331,8 @@ class TestStreamingSpeechWebSocket:
         assert captured_requests[0].stream is True
         assert captured_requests[0].response_format == "pcm"
         assert captured_requests[0].initial_codec_chunk_frames == 12
+        assert captured_timing["prepare_arrival"] == captured_timing["chunk_arrival"]
+        assert captured_timing["chunk_start"] > 0
         assert captured_tts_params == [{"_qwen3_tts_effective_max_tokens": [192]}]
         assert speech_service._generate_audio_bytes.await_count == 0
 
@@ -341,8 +365,9 @@ class TestStreamingSpeechWebSocket:
         speech_service.engine_client.abort = mocker.AsyncMock()
         speech_service.forced_aligner_enabled = True
 
-        async def mock_prepare_speech_generation(request):
+        async def mock_prepare_speech_generation(request, *, arrival_time=None):
             captured_requests.append(request)
+            assert arrival_time is not None
             return "req-stream", object(), {}
 
         speech_service._prepare_speech_generation = mock_prepare_speech_generation
@@ -353,8 +378,17 @@ class TestStreamingSpeechWebSocket:
         # The forced-aligner stage rides the same generator: its pooling output
         # is surfaced via the ``collect`` channel once the audio has streamed.
         async def mock_generate_pcm_chunks(
-            _generator, _request_id, *, include_sample_rate=False, tts_params=None, collect=None
+            _generator,
+            _request_id,
+            *,
+            request_start_s=None,
+            request_arrival_ts=None,
+            include_sample_rate=False,
+            tts_params=None,
+            collect=None,
         ):
+            assert request_start_s is not None
+            assert request_arrival_ts is not None
             for chunk in (first_chunk, second_chunk):
                 yield (chunk, 1000) if include_sample_rate else chunk
             if collect is not None:
@@ -438,7 +472,14 @@ class TestStreamingSpeechWebSocket:
         speech_service._prepare_speech_generation = mocker.AsyncMock(return_value=("req", object(), {}))
 
         async def mock_generate_pcm_chunks(
-            _generator, _request_id, *, include_sample_rate=False, tts_params=None, collect=None
+            _generator,
+            _request_id,
+            *,
+            request_start_s=None,
+            request_arrival_ts=None,
+            include_sample_rate=False,
+            tts_params=None,
+            collect=None,
         ):
             chunk = b"\x01" * 1000
             yield (chunk, 1000) if include_sample_rate else chunk
@@ -620,7 +661,15 @@ class TestStreamingSpeechWebSocket:
         speech_service.engine_client.abort = mocker.AsyncMock()
         speech_service.forced_aligner_enabled = False
 
-        async def mock_generate_pcm_chunks(_generator, _request_id, *, include_sample_rate=False, tts_params=None):
+        async def mock_generate_pcm_chunks(
+            _generator,
+            _request_id,
+            *,
+            request_start_s=None,
+            request_arrival_ts=None,
+            include_sample_rate=False,
+            tts_params=None,
+        ):
             yield b"\x01\x02"
             raise RuntimeError("stream boom")
 
@@ -716,7 +765,15 @@ class TestStreamingSpeechWebSocket:
         speech_service.engine_client.abort = mocker.AsyncMock()
         speech_service.forced_aligner_enabled = False
 
-        async def mock_generate_pcm_chunks(_generator, _request_id, *, include_sample_rate=False, tts_params=None):
+        async def mock_generate_pcm_chunks(
+            _generator,
+            _request_id,
+            *,
+            request_start_s=None,
+            request_arrival_ts=None,
+            include_sample_rate=False,
+            tts_params=None,
+        ):
             yield b"\x01\x02"
 
         speech_service._generate_pcm_chunks = mock_generate_pcm_chunks