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If multiple topologies map to the same number of cores, prefer default one. #838

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merged 2 commits into from
Nov 17, 2025
Merged

If multiple topologies map to the same number of cores, prefer default one. #838

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If multiple topologies map to the same number of cores, prefer defaul…
SikaGrr Nov 17, 2025
f7e4e0e
fix dangerous default value
SikaGrr Nov 17, 2025
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223 changes: 221 additions & 2 deletions src/xpk/core/system_characteristics.py
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Original file line number Diff line number Diff line change
Expand Up @@ -166,26 +166,34 @@ def get_tpu_system_characteristics_map(
supported_topologies: list[str],
supports_sub_slicing: bool,
tpu_type_requires_workload_policy: bool = False,
default_topologies: set[str] | None = None,
) -> dict[str, SystemCharacteristics]:
system_characteristics_map = {}
if default_topologies is None:
default_topologies = set()
for topology in supported_topologies:
chips_per_vm = compute_chips_per_vm(topology)
vms_per_slice = compute_vms_per_slice(topology)
num_tensorcores = compute_num_tensorcores(tensorcores_per_chip, topology)
device_type = f'{prefix}-{num_tensorcores}'
system = SystemCharacteristics(
topology=topology,
vms_per_slice=vms_per_slice,
gke_accelerator=gke_accelerator,
gce_machine_type=machine_type,
chips_per_vm=chips_per_vm,
accelerator_type=AcceleratorType.TPU,
device_type=f'{prefix}-{num_tensorcores}',
device_type=device_type,
requires_workload_policy=tpu_type_requires_workload_policy
and vms_per_slice > 1,
supports_sub_slicing=supports_sub_slicing,
)
system_characteristics_map[f'{prefix}-{topology}'] = system
system_characteristics_map[f'{prefix}-{num_tensorcores}'] = system
if (
topology in default_topologies
or device_type not in system_characteristics_map
):
system_characteristics_map[device_type] = system

return system_characteristics_map

Expand Down Expand Up @@ -373,6 +381,106 @@ def compute_vms_per_slice(topology: str) -> int:
tpu_type_requires_workload_policy=True,
supports_sub_slicing=False,
supported_topologies=generate_tpu_topologies(max_cubes=144),
default_topologies=set([
'12x12x12',
'12x12x16',
'12x12x20',
'12x12x24',
'12x12x28',
'12x12x36',
'12x16x16',
'12x16x20',
'12x16x24',
'12x16x28',
'12x20x20',
'12x20x24',
'12x24x24',
'16x16x16',
'16x16x20',
'16x16x24',
'16x16x32',
'16x20x28',
'16x24x24',
'2x2x1',
'2x2x2',
'2x2x4',
'2x4x4',
'4x12x116',
'4x12x12',
'4x12x124',
'4x12x20',
'4x12x28',
'4x12x44',
'4x12x52',
'4x12x68',
'4x12x76',
'4x12x92',
'4x20x20',
'4x20x28',
'4x20x44',
'4x20x52',
'4x20x68',
'4x20x76',
'4x28x28',
'4x28x44',
'4x28x52',
'4x4x116',
'4x4x12',
'4x4x124',
'4x4x148',
'4x4x164',
'4x4x172',
'4x4x188',
'4x4x20',
'4x4x212',
'4x4x236',
'4x4x244',
'4x4x28',
'4x4x4',
'4x4x44',
'4x4x52',
'4x4x68',
'4x4x76',
'4x4x8',
'4x4x92',
'4x8x116',
'4x8x12',
'4x8x124',
'4x8x148',
'4x8x164',
'4x8x172',
'4x8x188',
'4x8x20',
'4x8x28',
'4x8x44',
'4x8x52',
'4x8x68',
'4x8x76',
'4x8x8',
'4x8x92',
'8x12x12',
'8x12x16',
'8x12x20',
'8x12x28',
'8x12x44',
'8x12x52',
'8x16x16',
'8x16x20',
'8x16x28',
'8x16x44',
'8x20x20',
'8x20x28',
'8x8x12',
'8x8x16',
'8x8x20',
'8x8x28',
'8x8x44',
'8x8x52',
'8x8x68',
'8x8x76',
'8x8x8',
'8x8x92',
]),
),
**get_tpu_system_characteristics_map(
prefix='v6e',
Expand Down Expand Up @@ -405,6 +513,104 @@ def compute_vms_per_slice(topology: str) -> int:
machine_type='ct5p-hightpu-4t',
supports_sub_slicing=False,
supported_topologies=generate_tpu_topologies(max_cubes=140),
default_topologies=set([
'2x2x1',
'2x2x2',
'2x2x4',
'2x4x4',
'4x4x4',
'4x4x8',
'4x4x12',
'4x8x8',
'4x4x20',
'4x8x12',
'4x4x28',
'8x8x8',
'4x12x12',
'4x8x20',
'4x4x44',
'8x8x12',
'4x4x52',
'4x8x28',
'4x12x20',
'8x8x16',
'4x4x68',
'8x12x12',
'4x4x76',
'8x8x20',
'4x12x28',
'4x8x44',
'4x4x92',
'8x12x16',
'4x20x20',
'4x8x52',
'12x12x12',
'8x8x28',
'4x4x116',
'8x12x20',
'4x4x124',
'8x16x16',
'4x12x44',
'4x8x68',
'4x20x28',
'12x12x16',
'4x4x148',
'4x8x76',
'4x12x52',
'8x16x20',
'4x4x164',
'8x12x28',
'4x4x172',
'8x8x44',
'12x12x20',
'4x8x92',
'4x4x188',
'12x16x16',
'4x28x28',
'8x20x20',
'4x12x68',
'8x8x52',
'4x4x212',
'12x12x24',
'4x20x44',
'8x16x28',
'4x12x76',
'4x8x116',
'4x4x236',
'12x16x20',
'4x4x244',
'4x8x124',
'12x12x28',
'16x16x16',
'4x20x52',
'8x12x44',
'8x8x68',
'4x12x92',
'8x20x28',
'12x16x24',
'4x8x148',
'12x20x20',
'8x8x76',
'4x28x44',
'8x12x52',
'16x16x20',
'12x12x36',
'4x8x164',
'12x16x28',
'4x20x68',
'4x8x172',
'4x12x116',
'8x16x44',
'12x20x24',
'4x28x52',
'8x8x92',
'4x12x124',
'4x8x188',
'4x20x76',
'16x16x24',
'12x24x24',
'16x20x28',
]),
),
**get_tpu_system_characteristics_map(
prefix='v5litepod',
Expand All @@ -423,6 +629,19 @@ def compute_vms_per_slice(topology: str) -> int:
supported_topologies=generate_tpu_topologies(
max_cubes=64, enforce_nondecreasing=False
),
default_topologies=set([
'2x2x1',
'2x2x2',
'2x2x4',
'2x4x4',
'4x4x4',
'4x4x8',
'4x8x8',
'8x8x8',
'8x8x12',
'8x8x16',
'8x16x16',
]),
),
# CPU system characteristics.
# Note that chips_per_vm is actually the number of vCPUs in that CPU.
Expand Down
15 changes: 15 additions & 0 deletions src/xpk/core/system_characteristics_test.py
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -101,6 +101,21 @@ def test_get_tpu_system_characteristics_map_returns_correct_values_for_2x2x2_top
}


def test_get_tpu_system_characteristics_map_prefers_default_topologies():
result = get_tpu_system_characteristics_map(
prefix="test",
tensorcores_per_chip=2,
gke_accelerator="test",
machine_type="test",
supported_topologies=["4x4x4", "4x4x32", "4x8x16", "8x8x8"],
supports_sub_slicing=False,
default_topologies=set(["4x8x16"]),
)

assert result["test-128"].topology == "4x4x4"
assert result["test-1024"].topology == "4x8x16"


def test_generate_tpu_topologies_returns_correct_number_of_values_for_TPU_platforms():
v4 = generate_tpu_topologies(max_cubes=64, enforce_nondecreasing=False)
v5p = generate_tpu_topologies(max_cubes=140)
Expand Down
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