[Test] Fix scheduler fixtures after prefill burst counting (#40411)

Co-authored-by: Mohammad Angkad <mohammad.angkad@radixark.ai>
This commit is contained in:
Mohammad Miadh Angkad
2026-09-20 00:08:04 -07:00
committed by GitHub
co-authored by Mohammad Angkad
parent 99a44c88d4
commit 22f02cc339
2 changed files with 115 additions and 30 deletions
@@ -528,6 +528,7 @@ def test_pdmux_split_prefill_schedules_auxiliary_output_copy():
is_prebuilt=lambda: False,
is_split_prefill=lambda: True,
),
split_index=0,
reqs=[],
req_pool_indices=torch.tensor([3]),
input_ids=torch.tensor([5]),
@@ -24,6 +24,8 @@ from sglang.test.test_utils import CustomTestCase
register_cpu_ci(est_time=1, suite="base-a-test-cpu")
LAUNCH_TIMESTAMPS = (0.0, 0.125, 1.0, 1.125)
# Prefill busy time is charged launch -> result, so the result clock matters too.
RESULT_TIMESTAMPS = tuple(ts + 0.1 for ts in LAUNCH_TIMESTAMPS)
PP_MODULE = "sglang.srt.managers.scheduler_pp_mixin"
PDMUX_MODULE = "sglang.srt.multiplex.multiplexing_mixin"
@@ -32,6 +34,11 @@ class _BeforeModelForward(Exception):
pass
# The scheduler truncates once per recorded step, not once over the total.
def total_us(intervals):
return sum(int(interval * 1e6) for interval in intervals)
def load_mlx_scheduler_module():
# Run the real Python loop on CPU without importing a Metal runtime. Use a
# private module name so this cannot replace the installed MLX scheduler.
@@ -242,17 +249,61 @@ class TestSchedulerIdleStepCounters(CustomTestCase):
2 if chained else 0,
)
def test_split_prefill_is_charged_once_from_its_first_chunk(self):
# A split prefill spans several run_batch calls but yields one result,
# so only its first chunk may set the burst's start and its idle flag.
scheduler = self.make_scheduler([])
scheduler._sched_idled = True
batch = self.make_batch(ForwardMode.SPLIT_PREFILL)
for split_index, launch_ts in enumerate((0.0, 0.2, 0.4)):
batch.split_index = split_index
self.launch_batch(scheduler, batch, launch_ts)
self.assertEqual(scheduler.forward_ct, 3)
self.assertEqual(batch.forward_iter, 3)
self.assertEqual(batch.split_prefill_start, (1, 0.0))
self.assertTrue(batch.after_idle_gap)
self.record_result(scheduler, batch, 0.5)
# One charge for the whole burst: first chunk's launch to the result.
self.assertEqual(scheduler.total_prefill_busy_us, total_us([0.5 - 0.0]))
self.assertEqual(scheduler.total_prefill_uncached_tokens, 1024)
def test_a_prefill_is_not_charged_for_an_overlapping_earlier_one(self):
# An overlapped launch can precede the previous prefill's result; the
# span already charged to that prefill must not be charged twice.
scheduler = self.make_scheduler([])
prefill = self.make_batch(ForwardMode.EXTEND)
decode = self.make_batch(ForwardMode.DECODE, extend_num_tokens=None)
next_prefill = self.make_batch(ForwardMode.EXTEND)
# Both later batches launch while the first prefill is still in flight.
self.launch_batch(scheduler, prefill, 0.0)
self.launch_batch(scheduler, decode, 0.5)
self.launch_batch(scheduler, next_prefill, 0.6)
self.record_result(scheduler, prefill, 1.0)
self.record_result(scheduler, decode, 1.1)
self.record_result(scheduler, next_prefill, 1.5)
# 0.6 -> 1.0 already belongs to the first prefill, so the second one is
# charged from that result rather than from its own launch.
self.assertEqual(scheduler.total_prefill_busy_us, total_us([1.0, 0.5]))
self.assertEqual(scheduler.total_prefill_uncached_tokens, 2 * 1024)
# The decode broke contiguity, so it contributes no timing sample.
self.assertEqual(scheduler.decode_moment_totals[0], 0)
def make_batch(self, mode, *, launch_ts=None, extend_num_tokens=1024):
return ScheduleBatch(
reqs=[SimpleNamespace(rid="request", finished=Mock(return_value=False))],
forward_mode=mode,
spec_algorithm=SpeculativeAlgorithm.NONE,
launch_ts=launch_ts,
extend_num_tokens=extend_num_tokens,
)
def make_batches(self, mode):
return [
ScheduleBatch(
reqs=[
SimpleNamespace(rid="request", finished=Mock(return_value=False))
],
forward_mode=mode,
spec_algorithm=SpeculativeAlgorithm.NONE,
launch_ts=launch_ts,
extend_num_tokens=1024,
)
self.make_batch(mode, launch_ts=launch_ts)
for launch_ts in LAUNCH_TIMESTAMPS
]
@@ -261,20 +312,21 @@ class TestSchedulerIdleStepCounters(CustomTestCase):
observed_iters = []
def run_batch(batch, pp_proxy_tensors=None):
# Exercise the real timestamp, iteration, and flag handoff. Only
# model execution is stopped, at the scripted pre-forward hook.
with patch(
"sglang.srt.managers.scheduler.time.monotonic",
return_value=batch.launch_ts,
):
with self.assertRaises(_BeforeModelForward):
Scheduler.run_batch(scheduler, batch, pp_proxy_tensors)
# Exercise the real timestamp, iteration, and flag handoff.
self.launch_batch(
scheduler, batch, batch.launch_ts, pp_proxy_tensors=pp_proxy_tensors
)
return GenerationBatchResult()
def process_batch_result(batch, result):
observed_idle_flags.append(batch.after_idle_gap)
observed_iters.append(batch.forward_iter)
scheduler._record_step_counters(batch, result)
self.record_result(
scheduler,
batch,
RESULT_TIMESTAMPS[batch.forward_iter - 1],
result=result,
)
scheduler.run_batch = run_batch
scheduler.process_batch_result = process_batch_result
@@ -287,28 +339,60 @@ class TestSchedulerIdleStepCounters(CustomTestCase):
self.assertEqual(observed_idle_flags, [False, False, after_idle, False])
self.assertEqual(scheduler.forward_ct, 4)
self.assertEqual(observed_iters, [1, 2, 3, 4])
expected_intervals = [
LAUNCH_TIMESTAMPS[1] - LAUNCH_TIMESTAMPS[0],
LAUNCH_TIMESTAMPS[3] - LAUNCH_TIMESTAMPS[2],
]
if not after_idle:
expected_intervals.append(LAUNCH_TIMESTAMPS[2] - LAUNCH_TIMESTAMPS[1])
expected_samples = len(expected_intervals)
expected_busy_us = round(sum(expected_intervals) * 1_000_000)
if mode == ForwardMode.EXTEND:
self.assertEqual(scheduler.total_prefill_busy_us, expected_busy_us)
# A prefill is charged from the previous prefill's result, or from
# its own launch when none applies -- the first one, or after a gap.
expected_intervals = [
RESULT_TIMESTAMPS[0] - LAUNCH_TIMESTAMPS[0],
RESULT_TIMESTAMPS[1] - RESULT_TIMESTAMPS[0],
RESULT_TIMESTAMPS[2]
- (LAUNCH_TIMESTAMPS[2] if after_idle else RESULT_TIMESTAMPS[1]),
RESULT_TIMESTAMPS[3] - RESULT_TIMESTAMPS[2],
]
self.assertEqual(
scheduler.total_prefill_uncached_tokens, expected_samples * 1024
scheduler.total_prefill_busy_us, total_us(expected_intervals)
)
# Every prefill contributes its tokens; only the span is gap-aware.
self.assertEqual(
scheduler.total_prefill_uncached_tokens,
len(LAUNCH_TIMESTAMPS) * 1024,
)
else:
self.assertEqual(scheduler.decode_moment_totals[0], expected_samples)
self.assertEqual(scheduler.decode_moment_totals[2], expected_busy_us)
# Decode keeps launch-to-launch cadence and drops non-contiguous steps.
expected_intervals = [
LAUNCH_TIMESTAMPS[1] - LAUNCH_TIMESTAMPS[0],
LAUNCH_TIMESTAMPS[3] - LAUNCH_TIMESTAMPS[2],
]
if not after_idle:
expected_intervals.append(LAUNCH_TIMESTAMPS[2] - LAUNCH_TIMESTAMPS[1])
self.assertEqual(scheduler.decode_moment_totals[0], len(expected_intervals))
self.assertEqual(
scheduler.decode_moment_totals[2], total_us(expected_intervals)
)
def launch_batch(self, scheduler, batch, launch_ts, *, pp_proxy_tensors=None):
# Only model execution is stopped, at the scripted pre-forward hook.
with patch(
"sglang.srt.managers.scheduler.time.monotonic", return_value=launch_ts
):
with self.assertRaises(_BeforeModelForward):
Scheduler.run_batch(scheduler, batch, pp_proxy_tensors)
def record_result(self, scheduler, batch, result_ts, *, result=None):
# Prefill accounting reads the clock again when the result lands.
with patch(
"sglang.srt.managers.scheduler.time.monotonic", return_value=result_ts
):
scheduler._record_step_counters(
batch, GenerationBatchResult() if result is None else result
)
def make_scheduler(self, schedule):
scheduler = Scheduler.__new__(Scheduler)
scheduler._engine_paused = False
scheduler._sched_idled = False
scheduler._prev_step = None
scheduler._prev_prefill_end_ts = None
scheduler.forward_ct = 0
scheduler.processed_tokens_counter = 0
scheduler.spec_algorithm = SpeculativeAlgorithm.NONE