Files
kernbench2/benches/va_offset_verify.py
ywkang 357cab525b ADR-0026: DPPolicy intra-device only + ShardSpec structural coords
DPPolicy no longer carries a cross-SIP axis. SIP-level placement is
solely controlled by torch.ahbm.set_device(rank) (ADR-0024); DPPolicy
itself describes only the cube × PE layout within one SIP. ShardSpec
switches to structural (sip, cube, pe) coordinates; the flat pe_index
field/property is fully removed — silent drift between global-flat and
SIP-local interpretations was a foot-gun flagged by ADR-0024 D11.

Breaking API (explicit TypeError / AttributeError):
- DPPolicy(sip=...) / DPPolicy(num_sips=...) -> TypeError
- ShardSpec.pe_index -> AttributeError
- ShardSpec(pe_index=...) -> TypeError
- resolve_dp_policy now takes target_sip= (required), no num_sips.

Downstream migration:
- PE allocator dict keyed by (sip, cube, pe) tuples, in both
  _ensure_allocators and _free_tensor. deploy_tensor uses tuple lookup.
- _create_tensor passes target_sip=current_sip; post-hoc pe_index
  shifting removed entirely.
- launch._compute_local_shape drops the dp.sip branch.
- Internal resolvers (column_wise / row_wise / replicate / tiled_*)
  return _LocalPeShard (cube-local identifier) instead of ShardSpec —
  resolve_dp_policy lifts them to full structural coords.

Tests:
- New tests/test_adr0026_dppolicy_intra_device.py (12 tests) pins the
  contract end-to-end.
- test_sip_parallel.py rewritten: SIP composition now modeled as two
  resolve_dp_policy(target_sip=...) calls (ADR-0024 launcher style).
- Call-site migration: test_tensor, test_va_integration, test_va_offset,
  test_runtime_api_tensor, test_tl_recv_async, test_ccl_* and benches
  gemm_single_pe, gpt3_qkv, va_offset_verify, ccl_allreduce (legacy
  branch) all use intra-device DPPolicy and structural ShardSpec.

Result: 523 passed, 1 strict xfail (ring_default_ws — unchanged
ADR-0024 Phase B blocker; architectural fix deferred to ADR-0027).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-14 13:02:19 -07:00

43 lines
1.6 KiB
Python

"""VA offset verification benchmark.
Verifies that Triton-style base_ptr + pid * stride addressing works correctly
with intra-SIP TP sharding (cube/pe column_wise). Each PE loads its own
block from a sharded tensor and stores it back.
The kernel uses standard Triton patterns:
- tl.program_id(0) for PE index within cube
- tl.num_programs(0) for PE count within cube
- Shape args are automatically localized by launch()
"""
from kernbench.policy.placement.dp import DPPolicy
M, K = 128, 256
DTYPE = "f16"
def _copy_kernel(src_ptr, dst_ptr, M, K, tl, DTYPE="f16"):
"""Standard Triton copy kernel. M and K are cube-local (set by launch)."""
pid = tl.program_id(0)
num_pe = tl.num_programs(0)
cols_per_pe = K // num_pe
elem_bytes = 2 # f16
offset = pid * M * cols_per_pe * elem_bytes
data = tl.load(src_ptr + offset, shape=(M, cols_per_pe), dtype=DTYPE)
tl.store(dst_ptr + offset, data)
def run(torch):
"""Run the VA offset verification benchmark with full TP sharding."""
dp = DPPolicy(cube="column_wise", pe="column_wise")
src = torch.zeros((M, K), dtype=DTYPE, dp=dp, name="src")
dst = torch.empty((M, K), dtype=DTYPE, dp=dp, name="dst")
# launch() automatically converts M, K to cube-local values
torch.launch("va_offset_copy", _copy_kernel, src, dst, M, K)
# Sanity check: kernel completed with non-zero latency
kernel_traces = [t for t in torch._traces if t["phase"] == "kernel"]
assert len(kernel_traces) > 0, "No kernel traces recorded"
for kt in kernel_traces:
assert kt["total_ns"] > 0, f"Kernel latency is zero for {kt}"