Files
songtrace/tests/test_pipeline.py
branderson f187bfd6c0 Release the GPU after every stage
songtrace serve is long-lived but only wants the GPU in bursts, and until now
it kept everything it ever loaded. align cached wav2vec2 in a module dict that
was never cleared, torchcrepe caches its model on its own infer() function,
and even once the last reference to a model goes, PyTorch keeps the freed
blocks in its allocator rather than returning them to the driver. On a shared
box that is the whole GPU held against one idle process.

Stages now hand it back as soon as they are done with it. A stage that caches
a model registers how to drop it with @on_release, so models.py needs to know
nothing about the pipeline, and run_pipeline calls release() in a finally
after each stage — not once per job, because transcribe sits between separate
and align waiting on the Whisper server, which can be minutes of a GPU nothing
is using.

release() answers the bytes it handed back and the stage logs a line when that
is not zero, which is the only part of this visible from outside. It will not
initialise CUDA just to clean up after a run that never touched it.

The cost is reloading each model once per job rather than once per process,
seconds against stages that run for minutes. The CUDA context itself stays
until the process exits; releasing that would mean a subprocess per stage.
2026-09-29 00:01:20 -07:00

102 lines
4.4 KiB
Python

import json
from pathlib import Path
from songtrace.config import Config
from songtrace.pipeline import SongInput, Stage, read_warnings, run_pipeline, song_slug
def make_cfg(tmp_path):
return Config(whisper_url="http://x/v1", output_dir=tmp_path / "out",
work_dir=tmp_path / "work")
def make_inp():
return SongInput(title="T/est", artist="A", lyrics_text="la la")
def fake_stage(name, calls):
def outputs(ctx):
return [ctx.work / f"{name}.done"]
def run(ctx):
calls.append(name)
(ctx.work / f"{name}.done").write_text("x")
return Stage(name=name, outputs=outputs, run=run)
def test_slug_strips_slash():
assert song_slug(make_inp()) == "A - Test"
def test_runs_all_stages_then_skips_cached(tmp_path):
cfg, inp, calls = make_cfg(tmp_path), make_inp(), []
stages = [fake_stage("s1", calls), fake_stage("s2", calls)]
run_pipeline(inp, cfg, log=lambda m: None, stages=stages)
assert calls == ["s1", "s2"]
run_pipeline(inp, cfg, log=lambda m: None, stages=stages)
assert calls == ["s1", "s2"]
def test_force_from_reruns_tail(tmp_path):
cfg, inp, calls = make_cfg(tmp_path), make_inp(), []
stages = [fake_stage("s1", calls), fake_stage("s2", calls), fake_stage("s3", calls)]
run_pipeline(inp, cfg, log=lambda m: None, stages=stages)
calls.clear()
run_pipeline(inp, cfg, log=lambda m: None, stages=stages, force_from="s2")
assert calls == ["s2", "s3"]
def test_warnings_surfaced(tmp_path):
cfg, inp = make_cfg(tmp_path), make_inp()
def run(ctx):
(ctx.work / "notes_sec.json").write_text(
json.dumps({"notes": [], "breaks": [], "warnings": ["w1"]}))
(ctx.work / "n.done").write_text("x")
st = Stage(name="n", outputs=lambda ctx: [ctx.work / "n.done"], run=run)
result = run_pipeline(inp, cfg, log=lambda m: None, stages=[st])
assert result.warnings == ["w1"]
def test_read_warnings_is_empty_without_a_notes_file(tmp_path):
assert read_warnings(tmp_path) == []
def test_read_warnings_reads_the_notes_file(tmp_path):
(tmp_path / "notes_sec.json").write_text(json.dumps({"warnings": ["w1", "w2"]}))
assert read_warnings(tmp_path) == ["w1", "w2"]
def test_gpu_is_released_after_every_stage(tmp_path, monkeypatch):
"""Not just at the end: a later stage may wait minutes on the Whisper server."""
from songtrace import models
cfg, inp, calls = make_cfg(tmp_path), make_inp(), []
monkeypatch.setattr(models, "release", lambda: calls.append("release"))
stages = [fake_stage("s1", calls), fake_stage("s2", calls)]
run_pipeline(inp, cfg, log=lambda m: None, stages=stages)
assert calls == ["s1", "release", "s2", "release"]
def test_gpu_is_released_when_a_stage_fails(tmp_path, monkeypatch):
import pytest
from songtrace import models
from songtrace.pipeline import PipelineError
cfg, inp, calls = make_cfg(tmp_path), make_inp(), []
monkeypatch.setattr(models, "release", lambda: calls.append("release"))
def boom(ctx):
raise PipelineError("boom")
stages = [Stage(name="s1", outputs=lambda ctx: [ctx.work / "s1.done"], run=boom)]
with pytest.raises(PipelineError):
run_pipeline(inp, cfg, log=lambda m: None, stages=stages)
assert calls == ["release"]
def test_a_cached_stage_does_not_pay_for_a_release(tmp_path, monkeypatch):
from songtrace import models
cfg, inp, calls = make_cfg(tmp_path), make_inp(), []
stages = [fake_stage("s1", calls)]
run_pipeline(inp, cfg, log=lambda m: None, stages=stages)
calls.clear()
monkeypatch.setattr(models, "release", lambda: calls.append("release"))
run_pipeline(inp, cfg, log=lambda m: None, stages=stages)
assert calls == []
def test_a_release_that_freed_memory_is_reported_in_the_log(tmp_path, monkeypatch):
from songtrace import models
cfg, inp, lines = make_cfg(tmp_path), make_inp(), []
monkeypatch.setattr(models, "release", lambda: 512 * 2 ** 20)
run_pipeline(inp, cfg, log=lines.append, stages=[fake_stage("s1", [])])
assert "[s1] released 512 MiB of GPU memory" in lines
def test_a_release_that_freed_nothing_stays_out_of_the_log(tmp_path, monkeypatch):
from songtrace import models
cfg, inp, lines = make_cfg(tmp_path), make_inp(), []
monkeypatch.setattr(models, "release", lambda: 0)
run_pipeline(inp, cfg, log=lines.append, stages=[fake_stage("s1", [])])
assert not any("released" in line for line in lines)