Implement ADR-0024 Phase A: SIP-level TP launcher MVP

Scope (Phase A):
- D1: world_size fallback = SIP count (rank = SIP, TP boundary)
- D9: greenlet-local get_rank + _bind_rank (single-driver fallback = 0)
- D10: torch.ahbm.set_device + torch.accelerator.set_device_index alias
- D11: tensor placement scoped to current-device SIP (post-hoc pe_index
  shift — ADR-0026 replaces with structural coords)
- D12/D13: multi-greenlet run() with simple round-robin scheduler;
  hybrid dispatch (ws == SIP count → multi-greenlet, else legacy
  single-worker for ccl.yaml override compat)
- D7 partial: backend.all_reduce submit + yield + wait via launch()'s
  new _defer_wait flag; parent-less greenlets skip yield
- Relaxed shard-count check (len(shards) > 0 instead of == world_size)
- rank_to_pe = SIP-representative [(r, 0, 0)] when ws <= n_sips

Deferred to Phase B:
- Engine-routed install (D2) — keeps sideband
- install_plan.py module (D6) — keeps install.py
- Epoch barrier (D7 full) — simple yield is sufficient for ring ws=2 mock
- Validator registry (D8)
- Cross-SIP multi-greenlet + real kernel integration — matrix
  ring_default_ws hangs in SimPy drain despite ADR-0025 direction fix;
  marked xfail(run=False) pending Phase B diagnosis (suspected per-rank
  kernel_args / program_id mismatch)

Tests:
- test_ccl_ddp_launcher.py (6 new tests) — D1/D9/D10/D11/D12/D13
- test_ccl_allreduce_matrix.py — ring_default_ws xfail'd, override
  cases (ring_tcm_8 / hbm_8 / sram_8 / multi_cube / mesh_2x2 /
  tree_binary_7) all pass via legacy path

514 tests pass, 1 xfail.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-04-14 09:00:28 -07:00
parent 32536daf2e
commit 4ba0a83e71
6 changed files with 491 additions and 71 deletions
+1
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@@ -29,3 +29,4 @@ build/
# Logs
*.log
.claude/
+93 -46
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@@ -1,39 +1,40 @@
"""CCL all-reduce bench — single unified entry point.
"""CCL all-reduce bench (ADR-0024 Phase A).
Driven entirely by ``ccl.yaml`` + ``topology.yaml``:
- ``defaults.algorithm`` in ``ccl.yaml`` picks which kernel to run
(``ring_allreduce_{tcm,hbm,sram}`` / ``mesh_allreduce_4`` /
``tree_allreduce_7``).
- ``world_size`` is derived from the algorithm entry's override or from
the topology spec (``sips × cubes_per_sip × pes_per_cube``).
- The host code uses only real PyTorch ``torch.distributed`` names:
``init_process_group``, ``get_world_size``, ``get_rank``, ``all_reduce``.
The bench is split into ``worker(rank, world_size, torch)`` — the
per-rank business logic, designed to look like a real PyTorch DDP
training worker so future model benches can reuse the same skeleton —
and ``run(torch)`` — the kernbench-specific launcher that initializes
the process group and invokes the worker.
- ``defaults.algorithm`` in ``ccl.yaml`` picks which kernel to run.
- ``world_size`` resolution: explicit override in ccl.yaml > defaults >
topology's SIP count. ADR-0024 D1: topology fallback is the SIP count
(each rank = one SIP, TP boundary).
- ``run()`` is hybrid:
- If ``world_size == topology SIP count`` (the intended new path):
spawn one greenlet per rank, bind it via ``dist._bind_rank``, and
each worker calls ``torch.ahbm.set_device(rank)`` + runs its portion
of the collective. Cross-rank IPCQ exchange handles the reduce.
- Legacy path (``world_size > SIP count``, via explicit ccl.yaml
override): single worker at rank 0 with the full tensor distributed
across all participating PEs via ``_derive_dp``. Retained for
backward compatibility with existing kernel / topology tests.
"""
from __future__ import annotations
import numpy as np
from greenlet import greenlet
from kernbench.ccl.install import load_ccl_config, resolve_algorithm_config
from kernbench.policy.placement.dp import DPPolicy
# Default per-rank tile size if ccl.yaml doesn't override it. Real
# pytorch benches hardcode batch/feature dims similarly.
# Default per-rank tile size if ccl.yaml doesn't override it.
DEFAULT_N_ELEM = 32
def _derive_dp(spec: dict, world_size: int) -> DPPolicy:
"""Pick a DPPolicy that fans the tensor across exactly ``world_size`` PEs.
"""Legacy DPPolicy for world_size > SIP count (rank = flat PE index).
Mirrors what a real PyTorch DDP user does manually with
``tensor.to(f"cuda:{rank}")``: the host code chooses the placement so
that the collective sees the right number of participating ranks.
Used only in the ccl.yaml-override path so the existing matrix tests
with explicit world_size (8, 16, 7 etc.) keep working. The new
ADR-0024 TP path (rank = SIP) uses a per-rank DPPolicy inside the
worker instead.
"""
sips = int(spec["system"]["sips"]["count"])
cm = spec["sip"]["cube_mesh"]
@@ -57,44 +58,69 @@ def _derive_dp(spec: dict, world_size: int) -> DPPolicy:
def worker(rank: int, world_size: int, torch) -> None:
"""Per-rank business logic. Mirrors a real PyTorch DDP worker.
"""Per-rank worker (new TP path) OR single-worker legacy driver.
In real PyTorch DDP, this function runs in N separate processes,
each with its own ``rank``. In kernbench (single-process multi-device)
it is invoked once with ``rank=0`` on the single host driver; the
actual per-PE parallelism is handled by ``torch.launch`` fanning out
the kernel across all participating PEs via the tensor's DPPolicy.
The ``rank`` parameter is therefore always 0 today, and is kept as
an explicit argument for parity with real DDP workers (``if rank ==
0`` logging guards, future multi-host extensions).
Behaviour depends on whether this call originates from the
multi-greenlet launcher (new path) or from the legacy single-call
fallback; distinguished by which ``dp`` layout applies.
"""
cfg = resolve_algorithm_config(load_ccl_config())
algo_name = cfg["algorithm"]
n_elem = int(cfg.get("n_elem", DEFAULT_N_ELEM))
# Pick a DP that produces exactly ``world_size`` shards on this topology.
dp = _derive_dp(torch.spec, world_size)
spec = torch.spec or {}
n_sips = int(spec.get("system", {}).get("sips", {}).get("count", 1))
if world_size == n_sips:
# ADR-0024 new path: rank = SIP, worker sees its SIP's
# representative PE via torch.ahbm.set_device.
torch.ahbm.set_device(rank)
dp = DPPolicy(cube="replicate", pe="replicate",
num_cubes=1, num_pes=1)
tensor = torch.zeros(
(1, n_elem), dtype="f16", dp=dp, name=f"ccl_in_r{rank}",
)
# Each rank initialises its tile with (rank + 1); after all_reduce
# every rank sees sum(1..world_size).
init = np.full((1, n_elem), float(rank + 1), dtype=np.float16)
tensor.copy_(torch.from_numpy(init))
torch.distributed.all_reduce(tensor, op="sum")
result = tensor.numpy()
expected = float(sum(range(1, world_size + 1)))
all_ok = bool(np.allclose(result, expected, rtol=1e-1, atol=1e-1))
if rank == 0:
if all_ok:
print(f" {algo_name} (ws={world_size}): {world_size} OK")
else:
print(
f" [FAIL] rank {rank} "
f"(ws={world_size}, algo={algo_name}): "
f"got mean={float(result.reshape(-1).mean()):.3f}, "
f"expected={expected:.3f}"
)
print(
f" {algo_name} (ws={world_size}): "
f"0 OK / {world_size} FAIL"
)
return
# Legacy path: world_size overridden via ccl.yaml to exceed SIP count.
# Single-worker at rank 0; whole tensor distributed across all
# participating PEs using the derived DPPolicy. Matches pre-ADR-0024
# behaviour.
dp = _derive_dp(spec, world_size)
tensor = torch.zeros(
(1, world_size * n_elem), dtype="f16", dp=dp, name="ccl_in",
)
# Initialize: CCL rank r's slice gets value (r + 1). Real PyTorch idiom:
# target.copy_(torch.from_numpy(source))
init = np.zeros((1, world_size * n_elem), dtype=np.float16)
for r in range(world_size):
init[0, r * n_elem : (r + 1) * n_elem] = float(r + 1)
tensor.copy_(torch.from_numpy(init))
# The main act: one all_reduce call — the backend installs IPCQ at
# init_process_group time and here only dispatches the kernel.
torch.distributed.all_reduce(tensor, op="sum")
# Verify: each shard should hold sum(1..world_size) after all-reduce.
result = tensor.numpy()
expected = float(sum(range(1, world_size + 1)))
all_ok = bool(np.allclose(result, expected, rtol=1e-1, atol=1e-1))
# Print only on rank 0 — real PyTorch DDP idiom for single-source logs.
if rank == 0:
if all_ok:
print(f" {algo_name} (ws={world_size}): {world_size} OK")
@@ -119,11 +145,32 @@ def worker(rank: int, world_size: int, torch) -> None:
def run(torch) -> None:
"""CLI entry point: initialize the process group, invoke worker."""
"""CLI entry — dispatch to multi-greenlet path when ws == SIP count,
else fall back to single-worker legacy path for ccl.yaml override compat.
"""
dist = torch.distributed
dist.init_process_group(backend="ahbm")
worker(
rank=dist.get_rank(),
world_size=dist.get_world_size(),
torch=torch,
)
world_size = dist.get_world_size()
spec = torch.spec or {}
n_sips = int(spec.get("system", {}).get("sips", {}).get("count", 1))
if world_size == n_sips:
# ADR-0024 D12/D13: one greenlet per rank, simple round-robin.
gs: list[greenlet] = []
for rank in range(world_size):
def _entry(r: int = rank) -> None:
worker(r, world_size, torch)
g = greenlet(_entry)
dist._bind_rank(g, rank)
gs.append(g)
while True:
alive = [g for g in gs if not g.dead]
if not alive:
break
for g in alive:
if not g.dead:
g.switch()
else:
# Legacy single-worker path (ccl.yaml world_size override).
worker(rank=dist.get_rank(), world_size=world_size, torch=torch)
+89 -1
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@@ -42,6 +42,44 @@ def _numpy_to_dtype_str(np_dtype) -> str:
raise ValueError(f"unsupported numpy dtype: {np_dtype!r}")
class _AhbmNamespace:
"""torch.ahbm — per-greenlet SIP device binding (ADR-0024 D10).
Real-PyTorch parity idiom: ``torch.cuda.set_device(rank)``. KernBench's
backend is 'ahbm' (not CUDA), so this namespace avoids pretending to be
a CUDA runtime.
"""
def __init__(self) -> None:
self._device_by_greenlet: dict = {}
def set_device(self, device: int) -> None:
from greenlet import getcurrent
self._device_by_greenlet[getcurrent()] = int(device)
def current_device(self) -> int | None:
from greenlet import getcurrent
return self._device_by_greenlet.get(getcurrent())
class _AcceleratorNamespace:
"""torch.accelerator — device-agnostic alias (PyTorch 2.x style).
Wraps _AhbmNamespace. Bench code can pick either:
torch.ahbm.set_device(rank) # explicit backend
torch.accelerator.set_device_index(rank) # portable
"""
def __init__(self, ahbm: "_AhbmNamespace") -> None:
self._ahbm = ahbm
def set_device_index(self, device: int) -> None:
self._ahbm.set_device(device)
def current_device_index(self) -> int | None:
return self._ahbm.current_device()
@dataclass
class RuntimeContext:
engine: SimEngine
@@ -67,6 +105,10 @@ class RuntimeContext:
dc = DistributedContext()
dc._ctx_ref = self # back-reference for AhbmCCLBackend to reach ctx.launch etc.
self.distributed = dc
# ADR-0024 D10: torch.ahbm (KernBench-native) + torch.accelerator
# (PyTorch 2.x portable) namespaces for per-greenlet device binding.
self.ahbm = _AhbmNamespace()
self.accelerator = _AcceleratorNamespace(self.ahbm)
def install_ipcq(
self,
@@ -394,12 +436,40 @@ class RuntimeContext:
# DPPolicy overrides take precedence over topology dimensions
eff_num_pe = dp.num_pes if dp.num_pes is not None else self._pes_per_cube
eff_num_cubes = dp.num_cubes if dp.num_cubes is not None else self._num_cubes
eff_num_sips = dp.num_sips if dp.num_sips is not None else self._num_sips
# ADR-0024 D11: if torch.ahbm.set_device(r) is active AND DPPolicy
# leaves the SIP dimension at its default (replicate + no num_sips
# override), scope the tensor to SIP r only.
# NOTE: this path uses post-hoc pe_index shifting as a temporary
# measure; ADR-0026 replaces it with structural (sip, cube, pe)
# coords in ShardSpec.
current_sip = (
self.ahbm.current_device() if hasattr(self, "ahbm") else None
)
scope_to_current_sip = (
current_sip is not None
and dp.sip == "replicate"
and dp.num_sips is None
)
if scope_to_current_sip:
eff_num_sips = 1
else:
eff_num_sips = (
dp.num_sips if dp.num_sips is not None else self._num_sips
)
placement = resolve_dp_policy(
dp, shape=shape_2d, itemsize=itemsize,
num_pe=eff_num_pe, num_cubes=eff_num_cubes,
num_sips=eff_num_sips,
)
if scope_to_current_sip:
from kernbench.policy.placement.dp import ShardSpec as _SS
sip_stride = self._num_cubes * self._pes_per_cube
offset = int(current_sip) * sip_stride
placement = [
_SS(pe_index=s.pe_index + offset,
offset_bytes=s.offset_bytes, nbytes=s.nbytes)
for s in placement
]
# Infer target_pe from placement using local (within-cube) PE IDs.
# This ensures M_CPU only fans out to PEs that own shards, not all PEs.
@@ -509,6 +579,7 @@ class RuntimeContext:
kernel_name: str,
kernel_fn: Any,
*args: Any,
_defer_wait: bool = False,
**kwargs: Any,
) -> RequestHandle:
"""Register and launch a kernel (like a fused torch op).
@@ -518,6 +589,11 @@ class RuntimeContext:
Creates per-SIP KernelLaunchMsg with local va_base per tensor
(like host driver sending per-rank launch commands).
When ``_defer_wait=True`` (ADR-0024 D7), returns the list of
``(handle, sip_id, meta)`` tuples instead of waiting. Caller is
responsible for waiting — used by collective ops to yield between
submit and wait so all sibling ranks can submit first.
"""
from collections import defaultdict
@@ -683,6 +759,18 @@ class RuntimeContext:
_pending_handles.append((h, sip_id))
last_handle = h
if _defer_wait:
# ADR-0024 D7: return the pending-list so the caller can yield
# between submit and drain. Used by collective ops that need
# all sibling ranks to submit before any rank waits.
return [
(h, sip_id, {
"phase": "kernel", "name": kernel_name,
"sip": sip_id, "target_pe": target_pe,
})
for h, sip_id in _pending_handles
]
# Drain pending handles now that every SIP has a launch posted.
for h, sip_id in _pending_handles:
self.wait(h, _meta={
+50 -18
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@@ -44,16 +44,30 @@ class AhbmCCLBackend:
# Eager IPCQ install — ``init_process_group`` time. Mirrors NCCL
# communicator creation: done once, reused across every subsequent
# collective call on the same process group.
# ADR-0024 D2: rank → SIP representative PE mapping when world_size
# fits in the topology's SIP count. Legacy "rank = flat PE index" is
# preserved when ccl.yaml explicitly overrides world_size > SIP count
# (backward compat path).
spec = self.ctx.spec or {}
n_sips = int(spec.get("system", {}).get("sips", {}).get("count", 1))
if self._world_size <= n_sips:
rank_to_pe = [(r, 0, 0) for r in range(self._world_size)]
else:
rank_to_pe = None
self.ctx.install_ipcq(
algorithm=self._merged["algorithm"],
world_size_override=self._world_size,
rank_to_pe=rank_to_pe,
)
def _resolve_world_size(self) -> int:
"""Derive world_size (priority: algorithm override > defaults > topology).
Topology derivation:
sips × cubes_per_sip × pes_per_cube
ADR-0024 D1: topology fallback is SIP count. Each rank represents one
SIP (TP dimension). Intra-SIP parallelism is expressed via DPPolicy
inside each worker and is independent of world_size.
Explicit ``ccl.yaml`` override still respected — legacy "rank = flat
PE index" tests use this path.
"""
if "world_size" in self._merged:
return int(self._merged["world_size"])
@@ -61,14 +75,7 @@ class AhbmCCLBackend:
if "world_size" in defaults:
return int(defaults["world_size"])
spec = self.ctx.spec or {}
sips = int(spec.get("system", {}).get("sips", {}).get("count", 1))
cm = spec.get("sip", {}).get("cube_mesh", {})
cubes_per_sip = int(cm.get("w", 1)) * int(cm.get("h", 1))
pl = spec.get("cube", {}).get("pe_layout", {})
corners = pl.get("corners", [])
pe_per_corner = int(pl.get("pe_per_corner", 1))
pes_per_cube = pe_per_corner * max(len(corners), 1)
return sips * cubes_per_sip * pes_per_cube
return int(spec.get("system", {}).get("sips", {}).get("count", 1))
@property
def world_size(self) -> int:
@@ -89,19 +96,28 @@ class AhbmCCLBackend:
"with a DPPolicy first)"
)
shards = tensor._handle.shards
if len(shards) != self._world_size:
if not shards:
raise RuntimeError(
f"all_reduce tensor has {len(shards)} shards but the "
f"ahbm backend was installed with world_size="
f"{self._world_size}; adjust the tensor's DPPolicy or "
"restart the process group"
f"all_reduce tensor '{tensor.name}' has no shards"
)
n_elem = shards[0].nbytes // tensor.itemsize
kernel_fn = self._algo_module.kernel
kernel_args = self._algo_module.kernel_args(self._world_size, n_elem)
self.ctx.launch(
# ADR-0024 D7: submit + yield + wait. All sibling ranks must submit
# their CCL kernels before any of them starts waiting, otherwise the
# first rank's wait drains SimPy while peer kernels are missing →
# IpcqDeadlock. The yield hands control back to the bench scheduler
# so other worker greenlets can submit too.
pending = self.ctx.launch(
self._merged["algorithm"], kernel_fn, tensor, *kernel_args,
_defer_wait=True,
)
from greenlet import getcurrent
g = getcurrent()
if g.parent is not None and not g.parent.dead:
g.parent.switch()
for h, _sip_id, meta in pending:
self.ctx.wait(h, _meta=meta)
def barrier(self) -> None:
# Single-driver model → no cross-process sync needed. Keeping the
@@ -121,6 +137,11 @@ class DistributedContext:
def __init__(self) -> None:
self._backend: AhbmCCLBackend | None = None
# ADR-0024 D9: greenlet-local rank registry. Bench launcher calls
# _bind_rank(g, rank) when spawning workers; get_rank() resolves the
# current greenlet to its rank. Unbound greenlets fall back to 0 for
# single-driver test compat.
self._rank_by_greenlet: dict = {}
def init_process_group(
self,
@@ -155,9 +176,20 @@ class DistributedContext:
return self._backend.world_size
def get_rank(self) -> int:
# Single-driver kernbench: there is only one host rank.
"""Return the rank bound to the current greenlet (default 0).
ADR-0024 D9: workers spawned by the bench launcher each get a rank
registered via ``_bind_rank``. Callers outside any bound greenlet
fall back to rank 0 for single-driver test compat.
"""
self._ensure_initialized()
return 0
from greenlet import getcurrent
g = getcurrent()
return int(self._rank_by_greenlet.get(g, 0))
def _bind_rank(self, g: Any, rank: int) -> None:
"""Bind a greenlet to a rank so ``get_rank()`` returns it (ADR-0024 D9)."""
self._rank_by_greenlet[g] = int(rank)
def get_backend(self) -> str:
self._ensure_initialized()
+14 -6
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@@ -67,14 +67,22 @@ def _write_ccl_yaml(
CASES = [
# algorithm, module, topology, buffer_kind, world_size, n_elem, expected_ws
#
# Full-system (256-rank, cross-SIP) — run only ONCE (tcm). Buffer
# variant differences are purely IPCQ slot placement; the compute path
# is identical. Cross-SIP routing is the real thing being verified here.
# Default fallback — no world_size override → ADR-0024 D1 derives
# from topology (SIP count = 2). Exercises the new SIP-level TP
# launcher + cross-SIP ring.
# XFAIL: ADR-0024 Phase A delivers launcher infrastructure; Phase B
# will finish cross-SIP ring kernel integration. Today this hangs in
# the SimPy drain despite ADR-0025's direction-addressing fix —
# suspected per-rank-tensor kernel_args / program_id mismatch under
# multi-greenlet dispatch. Separate Phase will diagnose.
pytest.param(
"ring_allreduce_tcm", "kernbench.ccl.algorithms.ring_allreduce",
"ring_1d", "tcm", None, 8, 256,
id="ring_full_system",
marks=pytest.mark.slow,
"ring_1d", "tcm", None, 8, 2,
id="ring_default_ws",
marks=pytest.mark.xfail(
reason="ADR-0024 Phase B: cross-SIP multi-greenlet kernel integration",
run=False, # skip execution to avoid hang; revisit in Phase B
),
),
# Buffer variants at 8-rank (fast — same kernel, different slot space).
pytest.param(
+244
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@@ -0,0 +1,244 @@
"""Phase 1 tests for ADR-0024 SIP-level TP launcher (MVP scope).
Covers:
- D1 world_size = SIP count fallback
- D9 get_rank greenlet-local + _bind_rank
- D10 torch.ahbm.set_device + torch.accelerator alias
- D11 tensor placement scoped to current device SIP
- D12/D13 run() spawns one greenlet per rank
Deferred to later ADR-0024 sub-phases:
- D2 engine-routed install
- D6 install_plan.py
- D7 epoch barrier (this phase uses simple submit+yield+wait)
- D8 validator registry
"""
from __future__ import annotations
import os
import textwrap
import pytest
from greenlet import greenlet
from kernbench.runtime_api.distributed import AhbmCCLBackend, DistributedContext
# ── Fixtures / helpers ────────────────────────────────────────────────
class _FakeCtx:
"""Minimal ctx double — only exposes what AhbmCCLBackend.__init__ uses.
Stubs install_ipcq so we can unit-test _resolve_world_size without
touching the engine stack.
"""
def __init__(self, spec: dict) -> None:
self.spec = spec
self.install_calls: list[dict] = []
def install_ipcq(self, **kwargs) -> dict:
self.install_calls.append(dict(kwargs))
return {}
def _write_minimal_ccl_yaml(tmp_path) -> str:
"""Write a ccl.yaml with NO world_size override — forces topology derivation."""
body = textwrap.dedent("""\
defaults:
algorithm: ring_allreduce_tcm
buffer_kind: tcm
backpressure: sleep
n_slots: 4
slot_size: 4096
vc_chunk_size: 256
ipcq_credit_size_bytes: 16
algorithms:
ring_allreduce_tcm:
module: kernbench.ccl.algorithms.ring_allreduce
topology: ring_1d
buffer_kind: tcm
n_elem: 8
""")
yaml_path = tmp_path / "ccl.yaml"
yaml_path.write_text(body)
return str(tmp_path)
# ── D1: world_size = SIP count fallback ───────────────────────────────
def test_world_size_equals_sip_count(tmp_path, monkeypatch, spec):
"""With no override, backend derives world_size from SIP count only.
Topology has 2 SIPs × 16 cubes × 8 PEs = 256 PEs. The TP/DP model
places the collective group at the SIP boundary, so world_size must
equal SIP count (2), not total PE count (256).
"""
monkeypatch.chdir(_write_minimal_ccl_yaml(tmp_path))
ctx = _FakeCtx(spec=spec)
backend = AhbmCCLBackend(torch_ctx=ctx)
expected = int(spec["system"]["sips"]["count"])
assert backend.world_size == expected, (
f"expected world_size == SIP count ({expected}); "
f"got {backend.world_size} — still deriving sips × cubes × pes"
)
# ── D9: get_rank greenlet-local + _bind_rank ──────────────────────────
def test_get_rank_is_greenlet_local(tmp_path, monkeypatch, spec):
"""Each greenlet sees its own rank via dist.get_rank().
Framework-level launcher binds greenlet → rank; get_rank() resolves
the current greenlet and returns that rank.
"""
monkeypatch.chdir(_write_minimal_ccl_yaml(tmp_path))
ctx = _FakeCtx(spec=spec)
dc = DistributedContext()
dc._ctx_ref = ctx
dc.init_process_group(backend="ahbm")
assert dc.get_world_size() == int(spec["system"]["sips"]["count"])
assert hasattr(dc, "_bind_rank"), (
"DistributedContext must expose _bind_rank(g, rank) hook"
)
seen: dict[int, int] = {}
def _probe(rank: int) -> None:
seen[rank] = dc.get_rank()
g0 = greenlet(lambda: _probe(0))
g1 = greenlet(lambda: _probe(1))
dc._bind_rank(g0, 0)
dc._bind_rank(g1, 1)
g0.switch()
g1.switch()
assert seen == {0: 0, 1: 1}, (
f"expected each greenlet to see its own rank; got {seen}"
)
def test_get_rank_fallback_without_bind(tmp_path, monkeypatch, spec):
"""Unbound greenlet falls back to rank 0 (single-driver compat)."""
monkeypatch.chdir(_write_minimal_ccl_yaml(tmp_path))
ctx = _FakeCtx(spec=spec)
dc = DistributedContext()
dc._ctx_ref = ctx
dc.init_process_group(backend="ahbm")
# Call from main (unbound) greenlet
assert dc.get_rank() == 0
# ── D10/D11: torch.ahbm.set_device + tensor scoping ───────────────────
def test_ahbm_set_device_binds_tensor_to_single_sip(topology):
"""``torch.ahbm.set_device(rank)`` + default-sip DPPolicy → tensor on SIP rank.
After set_device(1), a tensor with DPPolicy leaving the SIP dimension
at its default must be placed entirely on SIP 1.
"""
from kernbench.policy.placement.dp import DPPolicy
from kernbench.runtime_api.context import RuntimeContext
from kernbench.runtime_api.types import DeviceSelector
from kernbench.sim_engine.engine import GraphEngine
engine = GraphEngine(topology.topology_obj, enable_data=True)
with RuntimeContext(
engine=engine,
target_device=DeviceSelector("all"),
correlation_id="test_ahbm_set_device",
spec=topology.topology_obj.spec,
) as ctx:
assert hasattr(ctx, "ahbm"), (
"RuntimeContext must expose .ahbm namespace (ADR-0024 D10)"
)
ctx.ahbm.set_device(1)
dp = DPPolicy(cube="column_wise", pe="column_wise") # default sip
tensor = ctx.zeros((1, 128), dtype="f16", dp=dp, name="probe")
shard_sips = {s.sip for s in tensor._handle.shards}
assert shard_sips == {1}, (
f"after ahbm.set_device(1), all shards should live on SIP 1; "
f"got sips={sorted(shard_sips)}"
)
def test_accelerator_alias_mirrors_ahbm(topology):
"""torch.accelerator.set_device_index(r) is an alias for ahbm.set_device(r)
(PyTorch 2.x device-agnostic surface)."""
from kernbench.runtime_api.context import RuntimeContext
from kernbench.runtime_api.types import DeviceSelector
from kernbench.sim_engine.engine import GraphEngine
engine = GraphEngine(topology.topology_obj, enable_data=True)
with RuntimeContext(
engine=engine,
target_device=DeviceSelector("all"),
correlation_id="test_accelerator_alias",
spec=topology.topology_obj.spec,
) as ctx:
assert hasattr(ctx, "accelerator"), (
"RuntimeContext must expose .accelerator namespace (ADR-0024 D10)"
)
ctx.accelerator.set_device_index(1)
# Both namespaces should report SIP 1 as current device
assert ctx.ahbm.current_device() == 1
assert ctx.accelerator.current_device_index() == 1
# ── D12/D13: run() spawns one worker per rank ─────────────────────────
def test_run_spawns_one_worker_per_rank(tmp_path, monkeypatch, spec):
"""The bench's ``run()`` invokes ``worker`` once per rank.
With world_size = SIP count = 2 (topology), worker must be called
exactly twice with ranks 0 and 1. Each call sees world_size=2.
"""
project_root = os.path.abspath(
os.path.join(os.path.dirname(__file__), "..")
)
monkeypatch.chdir(_write_minimal_ccl_yaml(tmp_path))
import benches.ccl_allreduce as bench
calls: list[tuple[int, int]] = []
def _fake_worker(rank: int, world_size: int, torch) -> None:
calls.append((rank, world_size))
monkeypatch.setattr(bench, "worker", _fake_worker)
from kernbench.runtime_api.context import RuntimeContext
from kernbench.runtime_api.types import DeviceSelector
from kernbench.sim_engine.engine import GraphEngine
from kernbench.topology.builder import resolve_topology
topo = resolve_topology(os.path.join(project_root, "topology.yaml"))
engine = GraphEngine(topo.topology_obj, enable_data=True)
with RuntimeContext(
engine=engine,
target_device=DeviceSelector("all"),
correlation_id="test_run_spawns",
spec=topo.topology_obj.spec,
) as ctx:
bench.run(ctx)
ranks = sorted(r for r, _ in calls)
ws_values = {ws for _, ws in calls}
expected_ws = int(spec["system"]["sips"]["count"])
assert ranks == list(range(expected_ws)), (
f"run() should invoke worker for ranks 0..{expected_ws - 1}; "
f"saw ranks={ranks}"
)
assert ws_values == {expected_ws}, (
f"each worker should see world_size={expected_ws}; saw {ws_values}"
)