Co-authored-by: Cheng Wan <54331508+ch-wan@users.noreply.github.com> Co-authored-by: Cheng Wan <chwan@rice.edu> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
286 lines
9.5 KiB
Python
286 lines
9.5 KiB
Python
"""Unit tests for the breakable CUDA graph mechanism.
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Tests the core capture/replay logic with simple tensor operations,
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verifying that graph breaks work correctly and outputs are properly
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propagated across segments.
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"""
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import unittest
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import torch
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from sglang.test.ci.ci_register import register_cuda_ci
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from sglang.test.test_utils import CustomTestCase
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# CI Registration
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register_cuda_ci(est_time=30, suite="stage-b-test-1-gpu-small")
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def _skip_if_no_cuda(test_func):
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return unittest.skipUnless(torch.cuda.is_available(), "CUDA not available")(
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test_func
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)
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def _skip_if_no_cuda_bindings(test_func):
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try:
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from cuda.bindings import runtime as rt # noqa: F401
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return test_func
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except ImportError:
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return unittest.skip("cuda-python not installed")(test_func)
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class TestBreakableCUDAGraphBasic(CustomTestCase):
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"""Test basic breakable CUDA graph capture and replay."""
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@classmethod
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def setUpClass(cls):
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if not torch.cuda.is_available():
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raise unittest.SkipTest("CUDA not available")
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try:
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from cuda.bindings import runtime # noqa: F401
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except ImportError:
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raise unittest.SkipTest("cuda-python not installed")
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from sglang.srt.model_executor.breakable_cuda_graph.breakable_cuda_graph import (
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BreakableCUDAGraph,
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BreakableCUDAGraphCapture,
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eager_on_graph,
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)
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cls.BreakableCUDAGraph = BreakableCUDAGraph
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cls.BreakableCUDAGraphCapture = BreakableCUDAGraphCapture
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cls.eager_on_graph = staticmethod(eager_on_graph)
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cls.device = torch.device("cuda:0")
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def test_no_break_capture_replay(self):
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"""Capture and replay without any graph breaks should work like normal CUDA graph."""
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x = torch.zeros(4, device=self.device)
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y = torch.zeros(4, device=self.device)
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graph = self.BreakableCUDAGraph()
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stream = torch.cuda.Stream(self.device)
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with self.BreakableCUDAGraphCapture(graph, stream=stream):
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y.copy_(x + 1.0)
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# Replay with new input
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x.fill_(5.0)
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graph.replay()
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torch.cuda.synchronize()
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self.assertTrue(torch.allclose(y, torch.full((4,), 6.0, device=self.device)))
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def test_single_break(self):
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"""A single graph break should split capture into two segments."""
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x = torch.zeros(4, device=self.device)
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intermediate = torch.zeros(4, device=self.device)
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y = torch.zeros(4, device=self.device)
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@self.eager_on_graph(enable=True)
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def eager_op(src):
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return src * 2.0
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graph = self.BreakableCUDAGraph()
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stream = torch.cuda.Stream(self.device)
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with self.BreakableCUDAGraphCapture(graph, stream=stream):
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intermediate.copy_(x + 1.0)
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broken = eager_op(intermediate)
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y.copy_(broken + 3.0)
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# Replay with new input
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x.fill_(10.0)
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graph.replay()
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torch.cuda.synchronize()
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# x=10 -> intermediate=11 -> eager: 11*2=22 -> y=22+3=25
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self.assertTrue(torch.allclose(y, torch.full((4,), 25.0, device=self.device)))
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def test_multiple_breaks(self):
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"""Multiple graph breaks should produce correct chained results."""
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x = torch.zeros(4, device=self.device)
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y = torch.zeros(4, device=self.device)
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@self.eager_on_graph(enable=True)
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def add_one(src):
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return src + 1.0
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@self.eager_on_graph(enable=True)
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def double(src):
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return src * 2.0
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graph = self.BreakableCUDAGraph()
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stream = torch.cuda.Stream(self.device)
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with self.BreakableCUDAGraphCapture(graph, stream=stream):
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t1 = x + 1.0 # graph segment 1
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t2 = add_one(t1) # break 1: eager
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t3 = t2 + 1.0 # graph segment 2
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t4 = double(t3) # break 2: eager
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y.copy_(t4) # graph segment 3
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# Replay: x=5 -> +1=6 -> add_one=7 -> +1=8 -> double=16
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x.fill_(5.0)
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graph.replay()
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torch.cuda.synchronize()
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self.assertTrue(torch.allclose(y, torch.full((4,), 16.0, device=self.device)))
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def test_eager_on_graph_disabled(self):
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"""@eager_on_graph(enable=False) should be a no-op passthrough."""
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@self.eager_on_graph(enable=False)
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def my_fn(x):
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return x + 1.0
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# Should just be the original function
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t = torch.tensor([1.0, 2.0], device=self.device)
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result = my_fn(t)
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self.assertTrue(
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torch.allclose(result, torch.tensor([2.0, 3.0], device=self.device))
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)
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def test_eager_on_graph_outside_capture(self):
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"""@eager_on_graph called outside capture should run the function directly."""
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@self.eager_on_graph(enable=True)
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def my_fn(x):
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return x + 1.0
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t = torch.tensor([1.0, 2.0], device=self.device)
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result = my_fn(t)
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self.assertTrue(
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torch.allclose(result, torch.tensor([2.0, 3.0], device=self.device))
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)
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def test_replay_updates_output(self):
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"""Replay should produce different results when input buffers change."""
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x = torch.zeros(4, device=self.device)
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y = torch.zeros(4, device=self.device)
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@self.eager_on_graph(enable=True)
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def scale(src):
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return src * 3.0
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graph = self.BreakableCUDAGraph()
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stream = torch.cuda.Stream(self.device)
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with self.BreakableCUDAGraphCapture(graph, stream=stream):
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t = x + 1.0
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t2 = scale(t)
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y.copy_(t2)
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# First replay: x=0 -> 0+1=1 -> 1*3=3
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graph.replay()
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torch.cuda.synchronize()
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self.assertTrue(torch.allclose(y, torch.full((4,), 3.0, device=self.device)))
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# Second replay: x=10 -> 10+1=11 -> 11*3=33
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x.fill_(10.0)
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graph.replay()
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torch.cuda.synchronize()
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self.assertTrue(torch.allclose(y, torch.full((4,), 33.0, device=self.device)))
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class TestCopyOutput(CustomTestCase):
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"""Test the _copy_output helper for structured output writeback."""
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@classmethod
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def setUpClass(cls):
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if not torch.cuda.is_available():
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raise unittest.SkipTest("CUDA not available")
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try:
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from cuda.bindings import runtime # noqa: F401
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except ImportError:
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raise unittest.SkipTest("cuda-python not installed")
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from sglang.srt.model_executor.breakable_cuda_graph.breakable_cuda_graph import (
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_copy_output,
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)
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cls._copy_output = staticmethod(_copy_output)
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cls.device = torch.device("cuda:0")
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def test_tensor_copy(self):
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dst = torch.zeros(4, device=self.device)
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src = torch.ones(4, device=self.device) * 5.0
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result = self._copy_output(dst, src)
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self.assertIs(result, dst)
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self.assertTrue(torch.allclose(dst, src))
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def test_dict_copy(self):
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dst = {
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"a": torch.zeros(4, device=self.device),
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"b": torch.zeros(4, device=self.device),
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}
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src = {
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"a": torch.ones(4, device=self.device),
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"b": torch.ones(4, device=self.device) * 2.0,
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}
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result = self._copy_output(dst, src)
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self.assertIs(result, dst)
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self.assertTrue(torch.allclose(dst["a"], torch.ones(4, device=self.device)))
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self.assertTrue(
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torch.allclose(dst["b"], torch.ones(4, device=self.device) * 2.0)
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)
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def test_object_copy(self):
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class FakeOutput:
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def __init__(self, t, label):
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self.tensor = t
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self.label = label
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dst = FakeOutput(torch.zeros(4, device=self.device), "old")
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src = FakeOutput(torch.ones(4, device=self.device) * 3.0, "new")
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result = self._copy_output(dst, src)
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self.assertIs(result, dst)
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self.assertTrue(
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torch.allclose(dst.tensor, torch.ones(4, device=self.device) * 3.0)
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)
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self.assertEqual(dst.label, "new")
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def test_non_tensor_fallback(self):
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result = self._copy_output(42, 99)
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self.assertEqual(result, 99)
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class TestBreakGraphHelper(CustomTestCase):
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"""Test the break_graph() convenience function."""
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@classmethod
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def setUpClass(cls):
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if not torch.cuda.is_available():
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raise unittest.SkipTest("CUDA not available")
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try:
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from cuda.bindings import runtime # noqa: F401
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except ImportError:
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raise unittest.SkipTest("cuda-python not installed")
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from sglang.srt.model_executor.breakable_cuda_graph.breakable_cuda_graph import (
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BreakableCUDAGraph,
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BreakableCUDAGraphCapture,
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break_graph,
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)
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cls.BreakableCUDAGraph = BreakableCUDAGraph
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cls.BreakableCUDAGraphCapture = BreakableCUDAGraphCapture
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cls.break_graph = staticmethod(break_graph)
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cls.device = torch.device("cuda:0")
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def test_break_graph_inserts_segment(self):
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"""break_graph() should insert a graph break even though it does nothing."""
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x = torch.zeros(4, device=self.device)
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y = torch.zeros(4, device=self.device)
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graph = self.BreakableCUDAGraph()
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stream = torch.cuda.Stream(self.device)
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with self.BreakableCUDAGraphCapture(graph, stream=stream):
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t = x + 1.0
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self.break_graph()
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y.copy_(t + 2.0)
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x.fill_(10.0)
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graph.replay()
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torch.cuda.synchronize()
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# x=10 -> +1=11 -> break -> +2=13
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self.assertTrue(torch.allclose(y, torch.full((4,), 13.0, device=self.device)))
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if __name__ == "__main__":
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unittest.main()
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