v29 (padded V, deadlocks), v30 (diag copy, works) — debugging epilogue deadlock with (128,128) PV

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2026-05-21 06:40:27 +00:00
parent 261fe5e43e
commit 6ec308dd50
3 changed files with 1057 additions and 0 deletions

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tests/test_stage_b_v29.py Normal file
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"""
Stage B v29: Pad V to (128,128), use (128,128) PV MMA.
V_padded = [V_real; zeros(64,128)]
O = P @ V_padded → (128, 128), but O[:, :64] = P @ V_real = correct
We only check the first 64 columns.
This avoids the (128,64) PV MMA deadlock and TMEM alias issues.
"""
import torch, cutlass, cutlass.cute as cute, cutlass.utils as utils, cutlass.pipeline as pipeline
from cutlass.cute.nvgpu import cpasync, tcgen05
from cutlass import Float32, BFloat16, Int32, Boolean, const_expr
from cutlass.utils import LayoutEnum
from cutlass.utils.tmem_allocator import find_tmem_tensor_col_offset
import cuda.bindings.driver as cuda
class StageBIdentitySoftmax:
def __init__(self, mma_tiler_mn, use_2cta_instrs=False, use_tma_store=True):
self.acc_dtype = Float32; self.qk_acc_dtype = Float32
self.q_dtype = BFloat16; self.o_dtype = BFloat16; self.c_dtype = BFloat16
self.use_2cta_instrs = use_2cta_instrs; self.use_tma_store = use_tma_store
self.mma_tiler_mn = mma_tiler_mn; self.mma_tiler = (*mma_tiler_mn, 1)
self.cluster_shape_mn = (1, 1)
self.cta_group = tcgen05.CtaGroup.TWO if use_2cta_instrs else tcgen05.CtaGroup.ONE
self.epilogue_warp_id = (0, 1, 2, 3)
self.mma_warp_id = 4; self.tma_warp_id = 5
self.threads_per_cta = 192
self.epilog_sync_bar_id = 1; self.tmem_alloc_sync_bar_id = 2; self.tmem_dealloc_sync_bar_id = 3
self.num_c_stage = 2
def _setup(self, qk_mma, pv_mma):
qk_inst_k = cute.size(qk_mma.shape_mnk, mode=[2])
self.qk_mma_tiler = (*self.mma_tiler_mn, qk_inst_k * 4)
self.pv_mma_tiler = (self.qk_mma_tiler[0], self.qk_mma_tiler[2], self.qk_mma_tiler[1])
self.mma_tiler = self.qk_mma_tiler
self.cta_tile_shape_mnk = (
self.qk_mma_tiler[0] // cute.size(qk_mma.thr_id.shape),
self.qk_mma_tiler[1],
self.qk_mma_tiler[2],
)
self.cluster_layout_vmnk = cute.tiled_divide(cute.make_layout((1,1,1)), (qk_mma.thr_id.shape,))
self.epi_tile = utils.sm100.compute_epilogue_tile_shape(
self.cta_tile_shape_mnk, self.use_2cta_instrs, self.c_layout, self.o_dtype)
self.num_ab_stage = 1; self.num_acc_stage = 1
self.a_smem_s = utils.sm100.make_smem_layout_a(qk_mma, self.mma_tiler, self.q_dtype, 1)
self.b_smem_s = utils.sm100.make_smem_layout_b(qk_mma, self.mma_tiler, self.b_dtype, 1)
self.v_smem_s = utils.sm100.make_smem_layout_b(pv_mma, self.pv_mma_tiler, self.b_dtype, 1)
self.p_tmem_s = utils.sm100.make_smem_layout_a(pv_mma, self.pv_mma_tiler, self.q_dtype, 1)
self.c_smem_s = utils.sm100.make_smem_layout_epi(self.o_dtype, self.c_layout, self.epi_tile, 2)
qk_thr = qk_mma.get_slice(0)
qk_acc_shape = qk_thr.partition_shape_C(self.qk_mma_tiler[:2])
tStS = qk_thr.make_fragment_C(qk_acc_shape)
s_cols = find_tmem_tensor_col_offset(tStS)
self.tilePlikeFP32 = self.qk_mma_tiler[1] // Float32.width * self.o_dtype.width
self.tmem_s0_offset = 0
self.tmem_p0_offset = 32
self.tmem_o0_offset = s_cols
tCtS_fake = qk_mma.make_fragment_C(cute.append(qk_acc_shape, self.num_acc_stage))
pv_thr = pv_mma.get_slice(0)
pv_acc_shape = pv_thr.partition_shape_C(self.pv_mma_tiler[:2])
tOtO = pv_thr.make_fragment_C(pv_acc_shape)
tCtO_fake = pv_mma.make_fragment_C(cute.append(pv_acc_shape, self.num_acc_stage))
self.num_tmem_alloc_cols = utils.get_num_tmem_alloc_cols([tCtS_fake, tCtO_fake], arch="sm_100")
a_smem = cute.slice_(self.a_smem_s, (None, None, None, 0))
b_smem = cute.slice_(self.b_smem_s, (None, None, None, 0))
self.num_tma_load_bytes = (
cute.size_in_bytes(self.q_dtype, a_smem) + cute.size_in_bytes(self.b_dtype, b_smem)
) * cute.size(qk_mma.thr_id.shape)
@cute.jit
def __call__(self, q: cute.Tensor, k: cute.Tensor, v: cute.Tensor, c: cute.Tensor, stream: cuda.CUstream):
self.q_dtype = q.element_type; self.b_dtype = k.element_type
self.o_dtype = c.element_type; self.c_dtype = self.o_dtype
self.a_major = LayoutEnum.from_tensor(q).mma_major_mode()
self.b_major = LayoutEnum.from_tensor(k).mma_major_mode()
self.v_major = LayoutEnum.from_tensor(v).mma_major_mode()
self.c_layout = LayoutEnum.from_tensor(c)
qk_mma = utils.sm100.make_trivial_tiled_mma(
self.q_dtype, self.b_dtype, self.a_major, self.b_major,
self.qk_acc_dtype, self.cta_group, self.mma_tiler_mn, tcgen05.OperandSource.SMEM)
pv_mma = utils.sm100.make_trivial_tiled_mma(
self.q_dtype, self.b_dtype, cute.nvgpu.OperandMajorMode.K, self.v_major,
self.qk_acc_dtype, self.cta_group, self.mma_tiler_mn, tcgen05.OperandSource.TMEM)
self._setup(qk_mma, pv_mma)
q_smem = cute.slice_(self.a_smem_s, (None, None, None, 0))
k_smem = cute.slice_(self.b_smem_s, (None, None, None, 0))
v_smem = cute.slice_(self.v_smem_s, (None, None, None, 0))
tma_q, tma_tq = cute.nvgpu.make_tiled_tma_atom_A(
utils.sm100.cluster_shape_to_tma_atom_A(self.cluster_shape_mn, qk_mma.thr_id),
q, q_smem, self.mma_tiler, qk_mma, self.cluster_layout_vmnk.shape)
tma_k, tma_tk = cute.nvgpu.make_tiled_tma_atom_B(
utils.sm100.cluster_shape_to_tma_atom_B(self.cluster_shape_mn, qk_mma.thr_id),
k, k_smem, self.mma_tiler, qk_mma, self.cluster_layout_vmnk.shape)
tma_v, tma_tv = cute.nvgpu.make_tiled_tma_atom_B(
utils.sm100.cluster_shape_to_tma_atom_B(self.cluster_shape_mn, pv_mma.thr_id),
v, v_smem, self.pv_mma_tiler, pv_mma, self.cluster_layout_vmnk.shape)
epi_smem = cute.select(self.c_smem_s, mode=[0, 1])
tma_c, tma_tc = cpasync.make_tiled_tma_atom(cpasync.CopyBulkTensorTileS2GOp(), c, epi_smem, self.epi_tile)
self._kernel(qk_mma, pv_mma, tma_q, tma_tq, tma_k, tma_tk, tma_v, tma_tv,
tma_c, tma_tc, self.cluster_layout_vmnk,
self.a_smem_s, self.b_smem_s, self.v_smem_s, self.p_tmem_s, self.c_smem_s, self.epi_tile
).launch(grid=(1,1,1), block=[self.threads_per_cta,1,1], stream=stream)
@cute.kernel
def _kernel(self, qk_mma, pv_mma, tma_q, mQ, tma_k, mK, tma_v, mV,
tma_c, mC, cl_vmnk, a_smem_s, b_smem_s, v_smem_s, p_tmem_s, c_smem_s, epi_tile):
warp_idx = cute.arch.make_warp_uniform(cute.arch.warp_idx())
tidx, _, _ = cute.arch.thread_idx()
use_2cta = cute.size(qk_mma.thr_id.shape) == 2
if warp_idx == self.tma_warp_id:
cpasync.prefetch_descriptor(tma_q); cpasync.prefetch_descriptor(tma_k)
cpasync.prefetch_descriptor(tma_v); cpasync.prefetch_descriptor(tma_c)
@cute.struct
class SS:
ab_bar: cute.struct.MemRange[cutlass.Int64, self.num_ab_stage * 2]
mma_si_bar: cute.struct.MemRange[cutlass.Int64, 2]
acc_bar: cute.struct.MemRange[cutlass.Int64, self.num_acc_stage * 2]
tmem_dealloc: cutlass.Int64
holding: cutlass.Int32
smem = utils.SmemAllocator(); st = smem.allocate(SS)
ab_p, ab_c = pipeline.PipelineTmaUmma.create(
barrier_storage=st.ab_bar.data_ptr(), num_stages=self.num_ab_stage,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread, 1),
tx_count=self.num_tma_load_bytes, cta_layout_vmnk=cl_vmnk, defer_sync=True
).make_participants()
mma_si_prod, mma_si_cons = pipeline.PipelineUmmaAsync.create(
barrier_storage=st.mma_si_bar.data_ptr(), num_stages=1,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread, 32 * len(self.epilogue_warp_id)),
).make_participants()
acc_pipe = pipeline.PipelineUmmaAsync.create(
barrier_storage=st.acc_bar.data_ptr(), num_stages=self.num_acc_stage,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(
pipeline.Agent.Thread, len(self.epilogue_warp_id) * (2 if use_2cta else 1)),
cta_layout_vmnk=cl_vmnk, defer_sync=True)
tmem_bar = pipeline.NamedBarrier(barrier_id=self.tmem_alloc_sync_bar_id,
num_threads=32 * len((self.mma_warp_id, *self.epilogue_warp_id)))
tmem = utils.TmemAllocator(st.holding.ptr, barrier_for_retrieve=tmem_bar,
allocator_warp_id=self.epilogue_warp_id[0], is_two_cta=use_2cta,
two_cta_tmem_dealloc_mbar_ptr=st.tmem_dealloc.ptr)
pipeline.pipeline_init_arrive(cluster_shape_mn=cl_vmnk, is_relaxed=True)
sQ = smem.allocate_tensor(element_type=self.q_dtype, layout=a_smem_s.outer, byte_alignment=128, swizzle=a_smem_s.inner)
sK = smem.allocate_tensor(element_type=self.b_dtype, layout=b_smem_s.outer, byte_alignment=128, swizzle=b_smem_s.inner)
sV = smem.allocate_tensor(element_type=self.b_dtype, layout=v_smem_s.outer, byte_alignment=128, swizzle=v_smem_s.inner)
sC = smem.allocate_tensor(element_type=self.o_dtype, layout=c_smem_s.outer, byte_alignment=128, swizzle=c_smem_s.inner)
gQ = cute.local_tile(mQ, cute.slice_(self.qk_mma_tiler, (None,0,None)), (None,None,None))
gK = cute.local_tile(mK, cute.slice_(self.qk_mma_tiler, (0,None,None)), (None,None,None))
gC = cute.local_tile(mC, cute.slice_(self.qk_mma_tiler, (None,None,0)), (None,None,None))
k_cnt = cute.size(gQ, mode=[3])
qk_thr = qk_mma.get_slice(0)
pv_thr = pv_mma.get_slice(0)
tCgQ = qk_thr.partition_A(gQ); tCgK = qk_thr.partition_B(gK); tCgC = qk_thr.partition_C(gC)
a_lay = cute.make_layout(cute.slice_(cl_vmnk, (0,0,None,0)).shape)
tAsQ, tAgQ = cpasync.tma_partition(tma_q, 0, a_lay, cute.group_modes(sQ,0,3), cute.group_modes(tCgQ,0,3))
b_lay = cute.make_layout(cute.slice_(cl_vmnk, (0,None,0,0)).shape)
tBsK, tBgK = cpasync.tma_partition(tma_k, 0, b_lay, cute.group_modes(sK,0,3), cute.group_modes(tCgK,0,3))
tAgQ = tAgQ[(None,0,None,0)]; tBgK = tBgK[(None,0,None,0)]
gV = cute.local_tile(mV, cute.slice_(self.pv_mma_tiler, (0,None,None)), (None,None,None))
tCgV = pv_thr.partition_B(gV)
tVsV, tVgV = cpasync.tma_partition(tma_v, 0, b_lay, cute.group_modes(sV,0,3), cute.group_modes(tCgV,0,3))
tVgV = tVgV[(None,0,None,0)]
tCrQ = qk_mma.make_fragment_A(sQ); tCrK = qk_mma.make_fragment_B(sK)
tCrV = pv_mma.make_fragment_B(sV)
qk_acc_shape = qk_thr.partition_shape_C(self.qk_mma_tiler[:2])
tStS = qk_thr.make_fragment_C(qk_acc_shape)
tStS0 = cute.make_tensor(tStS.iterator + self.tmem_s0_offset, tStS.layout)
pv_acc_shape = pv_thr.partition_shape_C(self.pv_mma_tiler[:2])
tOtO = pv_thr.make_fragment_C(pv_acc_shape)
tOtO0 = cute.make_tensor(tOtO.iterator + self.tmem_o0_offset, tOtO.layout)
tP = cute.make_tensor(tStS.iterator, p_tmem_s.outer)
tOrP_base = pv_thr.make_fragment_A(tP)
tOrP = tOrP_base[(None, None, None, 0)]
tOrP0 = cute.make_tensor(
tOrP.iterator + self.qk_acc_dtype.width // self.q_dtype.width * self.tmem_p0_offset,
tOrP.layout)
tCtS_fake = qk_mma.make_fragment_C(cute.append(qk_acc_shape, self.num_acc_stage))
tCtO_fake = pv_mma.make_fragment_C(cute.append(pv_acc_shape, self.num_acc_stage))
pipeline.pipeline_init_wait(cluster_shape_mn=cl_vmnk)
# ═══ TMA LOAD WARP (no tmem.wait_for_alloc) ═══
if warp_idx == self.tma_warp_id:
ab_p.reset(); peek = ab_p.try_acquire()
for kt in cutlass.range(k_cnt, unroll=1):
h = ab_p.acquire_and_advance(peek)
cute.copy(tma_q, tAgQ[(None,h.count)], tAsQ[(None,h.index)], tma_bar_ptr=h.barrier)
cute.copy(tma_k, tBgK[(None,h.count)], tBsK[(None,h.index)], tma_bar_ptr=h.barrier)
cute.copy(tma_v, tVgV[(None,h.count)], tVsV[(None,h.index)], tma_bar_ptr=h.barrier)
peek = cutlass.Boolean(1)
if h.count+1<k_cnt: peek = ab_p.try_acquire()
ab_p.tail()
# ═══ MMA WARP ═══
if warp_idx == self.mma_warp_id:
tmem.wait_for_alloc()
ab_c.reset(); peek = ab_c.try_wait()
s0_handle = mma_si_prod.acquire_and_advance()
acc_prod_st = pipeline.make_pipeline_state(pipeline.PipelineUserType.Producer, self.num_acc_stage)
acc_pipe.producer_acquire(acc_prod_st)
qk_mma.set(tcgen05.Field.ACCUMULATE, False)
for kt in range(k_cnt):
h = ab_c.wait_and_advance(peek)
nblk = cute.size(tCrQ, mode=[2])
for kb in cutlass.range(nblk, unroll_full=True):
cute.gemm(qk_mma, tStS0, tCrQ[(None,None,kb,h.index)], tCrK[(None,None,kb,h.index)], tStS0)
qk_mma.set(tcgen05.Field.ACCUMULATE, True)
h.release(); peek = cutlass.Boolean(1)
if h.count+1<k_cnt: peek = ab_c.try_wait()
cute.arch.fence_view_async_tmem_store()
s0_handle.commit()
s0_handle = mma_si_prod.acquire_and_advance()
pv_mma.set(tcgen05.Field.ACCUMULATE, False)
tCrV_s = tCrV[(None, None, None, 0)]
nblk_pv = cute.size(tOrP0, mode=[2])
for kb in cutlass.range(nblk_pv, unroll_full=True):
cute.gemm(pv_mma, tOtO0, tOrP0[(None,None,kb)], tCrV_s[(None,None,kb)], tOtO0)
pv_mma.set(tcgen05.Field.ACCUMULATE, True)
acc_pipe.producer_commit(acc_prod_st)
acc_prod_st.advance()
acc_pipe.producer_tail(acc_prod_st)
# ═══ EPILOGUE WARPS ═══
if warp_idx < self.mma_warp_id:
tmem.allocate(self.num_tmem_alloc_cols)
tmem.wait_for_alloc()
tmem_ptr = tmem.retrieve_ptr(self.qk_acc_dtype)
sfw_idx = tidx % (32 * len(self.epilogue_warp_id))
tmem_load_atom = cute.make_copy_atom(
tcgen05.copy.Ld32x32bOp(tcgen05.copy.Repetition(32)), self.qk_acc_dtype)
tiled_tmem_load = tcgen05.make_tmem_copy(tmem_load_atom, tStS0)
thr_load = tiled_tmem_load.get_slice(sfw_idx)
tTMEM_LOADtS = thr_load.partition_S(tStS0)
cS = cute.make_identity_tensor((self.qk_mma_tiler[0], self.qk_mma_tiler[1]))
tScS = qk_thr.partition_C(cS)
tTMEM_LOADcS = thr_load.partition_D(tScS)
tStS_P_layout = cute.composition(tStS.layout, cute.make_layout((128, self.tilePlikeFP32)))
tStS_P = cute.make_tensor(tStS.iterator + self.tmem_p0_offset, tStS_P_layout)
tmem_store_atom = cute.make_copy_atom(
tcgen05.copy.St32x32bOp(tcgen05.copy.Repetition(32)), self.qk_acc_dtype)
tiled_tmem_store = tcgen05.make_tmem_copy(tmem_store_atom, tStS_P)
thr_store = tiled_tmem_store.get_slice(sfw_idx)
tTMEM_STOREtS_x4 = thr_store.partition_D(tStS_P)
tScS_P_layout = cute.composition(tScS.layout, cute.make_layout((128, self.tilePlikeFP32)))
tScS_P = cute.make_tensor(tScS.iterator, tScS_P_layout)
tTMEM_STOREcS = thr_store.partition_S(tScS_P)
si_handle = mma_si_cons.wait_and_advance()
tTMEM_LOADrS = cute.make_rmem_tensor(tTMEM_LOADcS.shape, self.qk_acc_dtype)
cute.copy(tiled_tmem_load, tTMEM_LOADtS, tTMEM_LOADrS)
tTMEM_STORErS_x4 = cute.make_rmem_tensor(tTMEM_STOREcS.shape, self.qk_acc_dtype)
tTMEM_STORErS_x4_e = cute.make_tensor(
cute.recast_ptr(tTMEM_STORErS_x4.iterator, dtype=self.q_dtype),
tTMEM_LOADrS.layout)
frg_cnt = 4
frg_tile = cute.size(tTMEM_LOADrS) // frg_cnt
tTMEM_LOADrS_frg = cute.logical_divide(tTMEM_LOADrS, cute.make_layout(frg_tile))
tTMEM_STORErS_x4_e_frg = cute.logical_divide(
tTMEM_STORErS_x4_e, cute.make_layout(frg_tile))
for j in range(frg_cnt):
s_vec = tTMEM_LOADrS_frg[None, j].load()
tTMEM_STORErS_x4_e_frg[None, j].store(s_vec.to(self.q_dtype))
cute.copy(tiled_tmem_store, tTMEM_STORErS_x4, tTMEM_STOREtS_x4)
cute.arch.fence_view_async_tmem_store()
si_handle.release()
tCtO_base = cute.make_tensor(tmem_ptr + self.tmem_o0_offset, tCtO_fake.layout)
acc_cons_st = pipeline.make_pipeline_state(pipeline.PipelineUserType.Consumer, self.num_acc_stage)
c_grp = pipeline.CooperativeGroup(pipeline.Agent.Thread, 32 * len(self.epilogue_warp_id))
c_pipe = pipeline.PipelineTmaStore.create(num_stages=self.num_c_stage, producer_group=c_grp)
acc_cons_st = utils.gemm.sm100.epilogue_tma_store(
self, tidx, warp_idx, tma_c, tCtO_base, sC, tCgC,
epi_tile, 0, const_expr(lambda x: x), (0,0,0), acc_cons_st, acc_pipe, c_pipe)
c_pipe.producer_tail()
tmem.relinquish_alloc_permit()
tmem.free(tmem_ptr)
def test():
torch.manual_seed(42)
m, n, head_dim = 128, 128, 64
# Q, K: (seq, head_dim) = (128, 64)
q = torch.randn(m, head_dim, 1, dtype=torch.bfloat16, device='cuda')
k = torch.randn(n, head_dim, 1, dtype=torch.bfloat16, device='cuda')
# V: (head_dim, seq) MN-major = (64, 128) — pad to (128, 128) with zeros
v_real = torch.randn(head_dim, n, dtype=torch.bfloat16, device='cuda')
v_padded = torch.zeros(128, 128, dtype=torch.bfloat16, device='cuda')
v_padded[:head_dim, :] = v_real
v = v_padded.as_strided((128, 128), (1, 128)).unsqueeze(-1) # MN-major
# Output: (128, 128, 1) — we'll check only first 64 cols
c = torch.zeros(m, 128, 1, dtype=torch.bfloat16, device='cuda')
qf = q[:,:,0].float(); kf = k[:,:,0].float()
ref = qf @ kf.T @ v_real.float().T # (128, 64)
import cutlass.torch as ct
mQ = ct.from_dlpack(q).mark_layout_dynamic(leading_dim=ct.get_leading_dim(q))
mK = ct.from_dlpack(k).mark_layout_dynamic(leading_dim=ct.get_leading_dim(k))
mV = ct.from_dlpack(v).mark_layout_dynamic(leading_dim=ct.get_leading_dim(v))
mC = ct.from_dlpack(c).mark_layout_dynamic(leading_dim=ct.get_leading_dim(c))
stream = cuda.CUstream(torch.cuda.current_stream().cuda_stream)
kernel = StageBIdentitySoftmax(mma_tiler_mn=(128, 128), use_2cta_instrs=False, use_tma_store=True)
print('Compiling v29...', flush=True)
compiled = cute.compile(kernel, mQ, mK, mV, mC, stream)
print('Running v29...', flush=True)
compiled(mQ, mK, mV, mC, stream)
torch.cuda.synchronize()
out_full = c[:,:,0].float() # (128, 128)
out = out_full[:, :head_dim] # Only first 64 cols
cos = torch.nn.functional.cosine_similarity(out.flatten().unsqueeze(0), ref.flatten().unsqueeze(0)).item()
max_err = (out - ref).abs().max().item()
print('Stage B v29: V padded to (128,128), (128,128) PV MMA')
print(' Cosine: {:.6f}, Max error: {:.6f}'.format(cos, max_err))
print(' Full output stats: cols 0-63 range=[{:.4f},{:.4f}], cols 64-127 range=[{:.4f},{:.4f}]'.format(
out_full[:,:64].min().item(), out_full[:,:64].max().item(),
out_full[:,64:].min().item(), out_full[:,64:].max().item()))
print(' {}'.format('PASS' if cos >= 0.99 else 'FAIL'))
if __name__ == '__main__':
test()

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"""
Minimal PV-only test: Load P from GMEM to TMEM via QK-style MMA, then PV from TMEM.
Step 1: QK MMA writes FP32 S to TMEM (we know this works)
Step 2: Softmax packing writes BF16 P to TMEM (test this)
Step 3: PV MMA reads BF16 P from TMEM and V from SMEM, produces O
But to isolate the bug, let me test just the PV MMA in isolation.
I'll write known BF16 values to TMEM using the softmax packing path,
then immediately read them back using the PV A-fragment path,
and compare.
Actually, the simplest isolation test:
1. Do QK MMA to get S in TMEM (cosine 0.999999 verified)
2. Do softmax packing: S → P in TMEM (at offset 32)
3. Skip PV entirely — read P from TMEM using the C-fragment composition LOAD path
4. Output P to GMEM and compare against S.to(BF16)
This tests whether the softmax packing writes P correctly to the same TMEM
that the PV would read from.
But we can't easily read P from TMEM using the standard epilogue path
because the epilogue expects FP32 accumulator data.
Alternative: Use the PV MMA with V=I (identity). If P is correct,
then P @ I = P. But V needs to be MN-major and (128, 128), not (128, 64).
The output would be (128, 128) which doesn't match our (128, 64) c tensor.
Let me use V that selects the first 64 columns: V[k, n] = delta(k, n) for k in [0,63].
This gives P @ V = P[:, :64], and the output is (128, 64).
But V is (128, 128) in the MMA K,N dims. V[k, n] for k in [0,127], n in [0,63].
Hmm, this is getting complicated. Let me just do the identity approach with a (128, 128) output.
"""
import torch, cutlass, cutlass.cute as cute, cutlass.utils as utils, cutlass.pipeline as pipeline
from cutlass.cute.nvgpu import cpasync, tcgen05
from cutlass import Float32, BFloat16, Int32, Boolean, const_expr
from cutlass.utils import LayoutEnum
from cutlass.utils.tmem_allocator import find_tmem_tensor_col_offset
import cuda.bindings.driver as cuda
import cutlass.torch as ct
class PvDiagKernel:
"""QK + softmax packing + PV with V=I to isolate PV MMA correctness.
Output should be P = S.to(BF16), i.e. (Q@K^T).bfloat16()
With V=I, O = P @ I = P.
But V is (K=128, N=128) in the MMA. We need a 128x128 identity in MN-major.
Output tensor is (128, 128).
"""
def __init__(self, mma_tiler_mn):
self.acc_dtype = Float32; self.qk_acc_dtype = Float32
self.q_dtype = BFloat16; self.o_dtype = BFloat16; self.c_dtype = BFloat16
self.mma_tiler_mn = mma_tiler_mn; self.mma_tiler = (*mma_tiler_mn, 1)
self.use_2cta_instrs = False # needed by epilogue_tma_store
self.epilog_sync_bar_id = 1 # needed by epilogue_tma_store
self.cluster_shape_mn = (1, 1)
self.cta_group = tcgen05.CtaGroup.ONE
self.epilogue_warp_id = (0, 1, 2, 3)
self.mma_warp_id = 4; self.tma_warp_id = 5
self.threads_per_cta = 192
self.num_c_stage = 2
def _setup(self, qk_mma, pv_mma):
qk_inst_k = cute.size(qk_mma.shape_mnk, mode=[2])
self.qk_mma_tiler = (*self.mma_tiler_mn, qk_inst_k * 4)
# PV with V=I: output is (128, 128), same as QK
self.pv_mma_tiler = (self.qk_mma_tiler[0], self.qk_mma_tiler[1], self.qk_mma_tiler[1])
# pv_mma_tiler = (128, 128, 128) since V is 128x128
self.mma_tiler = self.qk_mma_tiler
self.cluster_layout_vmnk = cute.tiled_divide(cute.make_layout((1,1,1)), (qk_mma.thr_id.shape,))
self.cta_tile_shape_mnk = (
self.qk_mma_tiler[0] // cute.size(qk_mma.thr_id.shape),
self.qk_mma_tiler[1], self.qk_mma_tiler[2])
self.c_layout = LayoutEnum.ROW_MAJOR
self.epi_tile = utils.sm100.compute_epilogue_tile_shape(
self.cta_tile_shape_mnk, False, self.c_layout, self.o_dtype)
self.num_ab_stage = 1; self.num_acc_stage = 1
self.a_smem_s = utils.sm100.make_smem_layout_a(qk_mma, self.mma_tiler, self.q_dtype, 1)
self.b_smem_s = utils.sm100.make_smem_layout_b(qk_mma, self.mma_tiler, self.q_dtype, 1)
self.v_smem_s = utils.sm100.make_smem_layout_b(pv_mma, self.pv_mma_tiler, self.q_dtype, 1)
self.p_tmem_s = utils.sm100.make_smem_layout_a(pv_mma, self.pv_mma_tiler, self.q_dtype, 1)
self.c_smem_s = utils.sm100.make_smem_layout_epi(self.o_dtype, self.c_layout, self.epi_tile, 2)
qk_thr = qk_mma.get_slice(0)
qk_acc_shape = qk_thr.partition_shape_C(self.qk_mma_tiler[:2])
tStS = qk_thr.make_fragment_C(qk_acc_shape)
s_cols = find_tmem_tensor_col_offset(tStS)
pv_thr = pv_mma.get_slice(0)
pv_acc_shape = pv_thr.partition_shape_C(self.pv_mma_tiler[:2])
tOtO = pv_thr.make_fragment_C(pv_acc_shape)
o_cols = find_tmem_tensor_col_offset(tOtO)
self.tilePlikeFP32 = self.qk_mma_tiler[1] // Float32.width * self.o_dtype.width
self.tmem_s0_offset = 0
self.tmem_p0_offset = 32
self.tmem_o0_offset = s_cols
tCtS_fake = qk_mma.make_fragment_C(cute.append(qk_acc_shape, self.num_acc_stage))
tCtO_fake = pv_mma.make_fragment_C(cute.append(pv_acc_shape, self.num_acc_stage))
self.num_tmem_alloc_cols = utils.get_num_tmem_alloc_cols([tCtS_fake, tCtO_fake], arch="sm_100")
a_smem = cute.slice_(self.a_smem_s, (None, None, None, 0))
b_smem = cute.slice_(self.b_smem_s, (None, None, None, 0))
v_smem = cute.slice_(self.v_smem_s, (None, None, None, 0))
self.num_tma_load_bytes = (
cute.size_in_bytes(self.q_dtype, a_smem) + cute.size_in_bytes(self.q_dtype, b_smem) +
cute.size_in_bytes(self.q_dtype, v_smem)
) * cute.size(qk_mma.thr_id.shape)
@cute.jit
def __call__(self, q, k, v, c, stream):
self.q_dtype = q.element_type; self.o_dtype = c.element_type; self.c_dtype = self.o_dtype
self.a_major = LayoutEnum.from_tensor(q).mma_major_mode()
self.b_major = LayoutEnum.from_tensor(k).mma_major_mode()
self.v_major = LayoutEnum.from_tensor(v).mma_major_mode()
self.c_layout = LayoutEnum.from_tensor(c)
qk_mma = utils.sm100.make_trivial_tiled_mma(
self.q_dtype, self.q_dtype, self.a_major, self.b_major,
self.qk_acc_dtype, self.cta_group, self.mma_tiler_mn, tcgen05.OperandSource.SMEM)
# PV with 128x128 output (V=I)
pv_mma = utils.sm100.make_trivial_tiled_mma(
self.q_dtype, self.q_dtype, cute.nvgpu.OperandMajorMode.K, self.v_major,
self.qk_acc_dtype, self.cta_group, self.mma_tiler_mn, tcgen05.OperandSource.TMEM)
self._setup(qk_mma, pv_mma)
q_smem = cute.slice_(self.a_smem_s, (None, None, None, 0))
k_smem = cute.slice_(self.b_smem_s, (None, None, None, 0))
v_smem = cute.slice_(self.v_smem_s, (None, None, None, 0))
tma_q, tma_tq = cute.nvgpu.make_tiled_tma_atom_A(
utils.sm100.cluster_shape_to_tma_atom_A(self.cluster_shape_mn, qk_mma.thr_id),
q, q_smem, self.mma_tiler, qk_mma, self.cluster_layout_vmnk.shape)
tma_k, tma_tk = cute.nvgpu.make_tiled_tma_atom_B(
utils.sm100.cluster_shape_to_tma_atom_B(self.cluster_shape_mn, qk_mma.thr_id),
k, k_smem, self.mma_tiler, qk_mma, self.cluster_layout_vmnk.shape)
tma_v, tma_tv = cute.nvgpu.make_tiled_tma_atom_B(
utils.sm100.cluster_shape_to_tma_atom_B(self.cluster_shape_mn, pv_mma.thr_id),
v, v_smem, self.pv_mma_tiler, pv_mma, self.cluster_layout_vmnk.shape)
epi_smem = cute.select(self.c_smem_s, mode=[0, 1])
tma_c, tma_tc = cpasync.make_tiled_tma_atom(cpasync.CopyBulkTensorTileS2GOp(), c, epi_smem, self.epi_tile)
self._kernel(qk_mma, pv_mma, tma_q, tma_tq, tma_k, tma_tk, tma_v, tma_tv,
tma_c, tma_tc, self.cluster_layout_vmnk,
self.a_smem_s, self.b_smem_s, self.v_smem_s, self.p_tmem_s, self.c_smem_s, self.epi_tile
).launch(grid=(1,1,1), block=[self.threads_per_cta,1,1], stream=stream)
@cute.kernel
def _kernel(self, qk_mma, pv_mma, tma_q, mQ, tma_k, mK, tma_v, mV,
tma_c, mC, cl_vmnk, a_smem_s, b_smem_s, v_smem_s, p_tmem_s, c_smem_s, epi_tile):
warp_idx = cute.arch.make_warp_uniform(cute.arch.warp_idx())
tidx, _, _ = cute.arch.thread_idx()
use_2cta = cute.size(qk_mma.thr_id.shape) == 2
if warp_idx == self.tma_warp_id:
cpasync.prefetch_descriptor(tma_q); cpasync.prefetch_descriptor(tma_k)
cpasync.prefetch_descriptor(tma_v); cpasync.prefetch_descriptor(tma_c)
@cute.struct
class SS:
ab_bar: cute.struct.MemRange[cutlass.Int64, self.num_ab_stage * 2]
mma_si_bar: cute.struct.MemRange[cutlass.Int64, 2]
acc_bar: cute.struct.MemRange[cutlass.Int64, self.num_acc_stage * 2]
tmem_dealloc: cutlass.Int64
holding: cutlass.Int32
smem = utils.SmemAllocator(); st = smem.allocate(SS)
ab_p, ab_c = pipeline.PipelineTmaUmma.create(
barrier_storage=st.ab_bar.data_ptr(), num_stages=self.num_ab_stage,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread, 1),
tx_count=self.num_tma_load_bytes, cta_layout_vmnk=cl_vmnk, defer_sync=True
).make_participants()
mma_si_prod, mma_si_cons = pipeline.PipelineUmmaAsync.create(
barrier_storage=st.mma_si_bar.data_ptr(), num_stages=1,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread, 32 * len(self.epilogue_warp_id)),
).make_participants()
acc_pipe = pipeline.PipelineUmmaAsync.create(
barrier_storage=st.acc_bar.data_ptr(), num_stages=self.num_acc_stage,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(
pipeline.Agent.Thread, len(self.epilogue_warp_id) * (2 if use_2cta else 1)),
cta_layout_vmnk=cl_vmnk, defer_sync=True)
tmem_bar = pipeline.NamedBarrier(barrier_id=2,
num_threads=32 * len((self.mma_warp_id, *self.epilogue_warp_id)))
tmem = utils.TmemAllocator(st.holding.ptr, barrier_for_retrieve=tmem_bar,
allocator_warp_id=self.epilogue_warp_id[0], is_two_cta=use_2cta,
two_cta_tmem_dealloc_mbar_ptr=st.tmem_dealloc.ptr)
pipeline.pipeline_init_arrive(cluster_shape_mn=cl_vmnk, is_relaxed=True)
sQ = smem.allocate_tensor(element_type=self.q_dtype, layout=a_smem_s.outer, byte_alignment=128, swizzle=a_smem_s.inner)
sK = smem.allocate_tensor(element_type=self.q_dtype, layout=b_smem_s.outer, byte_alignment=128, swizzle=b_smem_s.inner)
sV = smem.allocate_tensor(element_type=self.q_dtype, layout=v_smem_s.outer, byte_alignment=128, swizzle=v_smem_s.inner)
sC = smem.allocate_tensor(element_type=self.o_dtype, layout=c_smem_s.outer, byte_alignment=128, swizzle=c_smem_s.inner)
gQ = cute.local_tile(mQ, cute.slice_(self.qk_mma_tiler, (None,0,None)), (None,None,None))
gK = cute.local_tile(mK, cute.slice_(self.qk_mma_tiler, (0,None,None)), (None,None,None))
gC = cute.local_tile(mC, cute.slice_(self.qk_mma_tiler, (None,None,0)), (None,None,None))
k_cnt = cute.size(gQ, mode=[3])
qk_thr = qk_mma.get_slice(0)
pv_thr = pv_mma.get_slice(0)
tCgQ = qk_thr.partition_A(gQ); tCgK = qk_thr.partition_B(gK); tCgC = qk_thr.partition_C(gC)
a_lay = cute.make_layout(cute.slice_(cl_vmnk, (0,0,None,0)).shape)
tAsQ, tAgQ = cpasync.tma_partition(tma_q, 0, a_lay, cute.group_modes(sQ,0,3), cute.group_modes(tCgQ,0,3))
b_lay = cute.make_layout(cute.slice_(cl_vmnk, (0,None,0,0)).shape)
tBsK, tBgK = cpasync.tma_partition(tma_k, 0, b_lay, cute.group_modes(sK,0,3), cute.group_modes(tCgK,0,3))
tAgQ = tAgQ[(None,0,None,0)]; tBgK = tBgK[(None,0,None,0)]
gV = cute.local_tile(mV, cute.slice_(self.pv_mma_tiler, (0,None,None)), (None,None,None))
tCgV = pv_thr.partition_B(gV)
tVsV, tVgV = cpasync.tma_partition(tma_v, 0, b_lay, cute.group_modes(sV,0,3), cute.group_modes(tCgV,0,3))
tVgV = tVgV[(None,0,None,0)]
tCrQ = qk_mma.make_fragment_A(sQ); tCrK = qk_mma.make_fragment_B(sK)
tCrV = pv_mma.make_fragment_B(sV)
qk_acc_shape = qk_thr.partition_shape_C(self.qk_mma_tiler[:2])
tStS = qk_thr.make_fragment_C(qk_acc_shape)
tStS0 = cute.make_tensor(tStS.iterator + self.tmem_s0_offset, tStS.layout)
pv_acc_shape = pv_thr.partition_shape_C(self.pv_mma_tiler[:2])
tOtO = pv_thr.make_fragment_C(pv_acc_shape)
tOtO0 = cute.make_tensor(tOtO.iterator + self.tmem_o0_offset, tOtO.layout)
tP = cute.make_tensor(tStS.iterator, p_tmem_s.outer)
tOrP_base = pv_thr.make_fragment_A(tP)
tOrP = tOrP_base[(None, None, None, 0)]
tOrP0 = cute.make_tensor(
tOrP.iterator + self.qk_acc_dtype.width // self.q_dtype.width * self.tmem_p0_offset,
tOrP.layout)
tCtS_fake = qk_mma.make_fragment_C(cute.append(qk_acc_shape, self.num_acc_stage))
tCtO_fake = pv_mma.make_fragment_C(cute.append(pv_acc_shape, self.num_acc_stage))
pipeline.pipeline_init_wait(cluster_shape_mn=cl_vmnk)
# ═══ TMA LOAD WARP ═══
if warp_idx == self.tma_warp_id:
ab_p.reset(); peek = ab_p.try_acquire()
for kt in cutlass.range(k_cnt, unroll=1):
h = ab_p.acquire_and_advance(peek)
cute.copy(tma_q, tAgQ[(None,h.count)], tAsQ[(None,h.index)], tma_bar_ptr=h.barrier)
cute.copy(tma_k, tBgK[(None,h.count)], tBsK[(None,h.index)], tma_bar_ptr=h.barrier)
cute.copy(tma_v, tVgV[(None,h.count)], tVsV[(None,h.index)], tma_bar_ptr=h.barrier)
peek = cutlass.Boolean(1)
if h.count+1<k_cnt: peek = ab_p.try_acquire()
ab_p.tail()
# ═══ MMA WARP ═══
if warp_idx == self.mma_warp_id:
tmem.wait_for_alloc()
ab_c.reset(); peek = ab_c.try_wait()
s0_handle = mma_si_prod.acquire_and_advance()
acc_prod_st = pipeline.make_pipeline_state(pipeline.PipelineUserType.Producer, self.num_acc_stage)
acc_pipe.producer_acquire(acc_prod_st)
qk_mma.set(tcgen05.Field.ACCUMULATE, False)
for kt in range(k_cnt):
h = ab_c.wait_and_advance(peek)
nblk = cute.size(tCrQ, mode=[2])
for kb in cutlass.range(nblk, unroll_full=True):
cute.gemm(qk_mma, tStS0, tCrQ[(None,None,kb,h.index)], tCrK[(None,None,kb,h.index)], tStS0)
qk_mma.set(tcgen05.Field.ACCUMULATE, True)
h.release(); peek = cutlass.Boolean(1)
if h.count+1<k_cnt: peek = ab_c.try_wait()
cute.arch.fence_view_async_tmem_store()
s0_handle.commit()
s0_handle = mma_si_prod.acquire_and_advance()
# PV MMA: P @ V where V=I → O = P
pv_mma.set(tcgen05.Field.ACCUMULATE, False)
tCrV_s = tCrV[(None, None, None, 0)]
nblk_pv = cute.size(tOrP0, mode=[2])
for kb in cutlass.range(nblk_pv, unroll_full=True):
cute.gemm(pv_mma, tOtO0, tOrP0[(None,None,kb)], tCrV_s[(None,None,kb)], tOtO0)
pv_mma.set(tcgen05.Field.ACCUMULATE, True)
acc_pipe.producer_commit(acc_prod_st)
acc_prod_st.advance()
acc_pipe.producer_tail(acc_prod_st)
# ═══ EPILOGUE WARPS ═══
if warp_idx < self.mma_warp_id:
tmem.allocate(self.num_tmem_alloc_cols)
tmem.wait_for_alloc()
tmem_ptr = tmem.retrieve_ptr(self.qk_acc_dtype)
sfw_idx = tidx % (32 * len(self.epilogue_warp_id))
tmem_load_atom = cute.make_copy_atom(
tcgen05.copy.Ld32x32bOp(tcgen05.copy.Repetition(32)), self.qk_acc_dtype)
tiled_tmem_load = tcgen05.make_tmem_copy(tmem_load_atom, tStS0)
thr_load = tiled_tmem_load.get_slice(sfw_idx)
tTMEM_LOADtS = thr_load.partition_S(tStS0)
cS = cute.make_identity_tensor((self.qk_mma_tiler[0], self.qk_mma_tiler[1]))
tScS = qk_thr.partition_C(cS)
tTMEM_LOADcS = thr_load.partition_D(tScS)
tStS_P_layout = cute.composition(tStS.layout, cute.make_layout((128, self.tilePlikeFP32)))
tStS_P = cute.make_tensor(tStS.iterator + self.tmem_p0_offset, tStS_P_layout)
tmem_store_atom = cute.make_copy_atom(
tcgen05.copy.St32x32bOp(tcgen05.copy.Repetition(32)), self.qk_acc_dtype)
tiled_tmem_store = tcgen05.make_tmem_copy(tmem_store_atom, tStS_P)
thr_store = tiled_tmem_store.get_slice(sfw_idx)
tTMEM_STOREtS_x4 = thr_store.partition_D(tStS_P)
tScS_P_layout = cute.composition(tScS.layout, cute.make_layout((128, self.tilePlikeFP32)))
tScS_P = cute.make_tensor(tScS.iterator, tScS_P_layout)
tTMEM_STOREcS = thr_store.partition_S(tScS_P)
si_handle = mma_si_cons.wait_and_advance()
tTMEM_LOADrS = cute.make_rmem_tensor(tTMEM_LOADcS.shape, self.qk_acc_dtype)
cute.copy(tiled_tmem_load, tTMEM_LOADtS, tTMEM_LOADrS)
tTMEM_STORErS_x4 = cute.make_rmem_tensor(tTMEM_STOREcS.shape, self.qk_acc_dtype)
tTMEM_STORErS_x4_e = cute.make_tensor(
cute.recast_ptr(tTMEM_STORErS_x4.iterator, dtype=self.q_dtype),
tTMEM_LOADrS.layout)
frg_cnt = 4
frg_tile = cute.size(tTMEM_LOADrS) // frg_cnt
tTMEM_LOADrS_frg = cute.logical_divide(tTMEM_LOADrS, cute.make_layout(frg_tile))
tTMEM_STORErS_x4_e_frg = cute.logical_divide(
tTMEM_STORErS_x4_e, cute.make_layout(frg_tile))
for j in range(frg_cnt):
s_vec = tTMEM_LOADrS_frg[None, j].load()
tTMEM_STORErS_x4_e_frg[None, j].store(s_vec.to(self.q_dtype))
cute.copy(tiled_tmem_store, tTMEM_STORErS_x4, tTMEM_STOREtS_x4)
cute.arch.fence_view_async_tmem_store()
si_handle.release()
# Output epilogue
tCtO_base = cute.make_tensor(tmem_ptr + self.tmem_o0_offset, tCtO_fake.layout)
acc_cons_st = pipeline.make_pipeline_state(pipeline.PipelineUserType.Consumer, self.num_acc_stage)
c_grp = pipeline.CooperativeGroup(pipeline.Agent.Thread, 32 * len(self.epilogue_warp_id))
c_pipe = pipeline.PipelineTmaStore.create(num_stages=self.num_c_stage, producer_group=c_grp)
acc_cons_st = utils.gemm.sm100.epilogue_tma_store(
self, tidx, warp_idx, tma_c, tCtO_base, sC, tCgC,
epi_tile, 0, const_expr(lambda x: x), (0,0,0), acc_cons_st, acc_pipe, c_pipe)
c_pipe.producer_tail()
tmem.relinquish_alloc_permit()
tmem.free(tmem_ptr)
def test():
torch.manual_seed(42)
m, n, head_dim = 128, 128, 64
q = torch.randn(m, head_dim, 1, dtype=torch.bfloat16, device='cuda')
k = torch.randn(n, head_dim, 1, dtype=torch.bfloat16, device='cuda')
# V = identity (128x128) in MN-major: (128,128) with strides (1,128)
v = torch.eye(128, dtype=torch.bfloat16, device='cuda')
# MN-major: (128,128) with strides (1,128) — row is fast dim
v = v.as_strided((128, 128), (1, 128)).unsqueeze(-1)
c = torch.zeros(m, n, 1, dtype=torch.bfloat16, device='cuda')
qf = q[:,:,0].float(); kf = k[:,:,0].float()
# With V=I and identity softmax: O = (Q@K^T).bf16() @ I = (Q@K^T).bf16()
ref = (qf @ kf.T).bfloat16().float()
mQ = ct.from_dlpack(q).mark_layout_dynamic(leading_dim=ct.get_leading_dim(q))
mK = ct.from_dlpack(k).mark_layout_dynamic(leading_dim=ct.get_leading_dim(k))
mV = ct.from_dlpack(v).mark_layout_dynamic(leading_dim=ct.get_leading_dim(v))
mC = ct.from_dlpack(c).mark_layout_dynamic(leading_dim=ct.get_leading_dim(c))
stream = cuda.CUstream(torch.cuda.current_stream().cuda_stream)
kernel = PvDiagKernel(mma_tiler_mn=(128, 128))
print('Compiling...', flush=True)
compiled = cute.compile(kernel, mQ, mK, mV, mC, stream)
print('Running...', flush=True)
compiled(mQ, mK, mV, mC, stream)
torch.cuda.synchronize()
out = c[:,:,0].float()
cos = torch.nn.functional.cosine_similarity(out.flatten().unsqueeze(0), ref.flatten().unsqueeze(0)).item()
print('PV diag (V=I): cosine {:.6f} {}'.format(cos, 'PASS' if cos >= 0.99 else 'FAIL'))
if __name__ == '__main__':
test()

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tests/test_v28c_noepi.py Normal file
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"""
Stage B v28c: Debug deadlock.
Skip the epilogue. Just do QK + softmax packing + PV MMA.
Verify PV MMA completes (no deadlock).
"""
import torch, cutlass, cutlass.cute as cute, cutlass.utils as utils, cutlass.pipeline as pipeline
from cutlass.cute.nvgpu import cpasync, tcgen05
from cutlass import Float32, BFloat16, Int32, Boolean, const_expr
from cutlass.utils import LayoutEnum
from cutlass.utils.tmem_allocator import find_tmem_tensor_col_offset
import cuda.bindings.driver as cuda
class StageBNoEpi:
def __init__(self, pv_mn, use_2cta_instrs=False):
self.pv_mn = pv_mn
self.qk_acc_dtype = Float32; self.q_dtype = BFloat16; self.b_dtype = BFloat16
self.o_dtype = BFloat16; self.c_dtype = BFloat16; self.acc_dtype = Float32
self.use_2cta_instrs = use_2cta_instrs
self.mma_tiler_mn = (128, 128); self.cluster_shape_mn = (1, 1)
self.cta_group = tcgen05.CtaGroup.TWO if use_2cta_instrs else tcgen05.CtaGroup.ONE
self.epilogue_warp_id = (0, 1, 2, 3)
self.mma_warp_id = 4; self.tma_warp_id = 5
self.threads_per_cta = 192
self.tmem_alloc_sync_bar_id = 2; self.tmem_dealloc_sync_bar_id = 3
self.num_ab_stage = 1; self.num_acc_stage = 1
def _setup(self, qk_mma, pv_mma):
qk_inst_k = cute.size(qk_mma.shape_mnk, mode=[2])
self.qk_mma_tiler = (*self.mma_tiler_mn, qk_inst_k * 4)
self.pv_mma_tiler = (self.qk_mma_tiler[0], self.qk_mma_tiler[2], self.qk_mma_tiler[1])
self.mma_tiler = self.qk_mma_tiler
self.cluster_layout_vmnk = cute.tiled_divide(cute.make_layout((1,1,1)), (qk_mma.thr_id.shape,))
self.num_ab_stage = 1; self.num_acc_stage = 1
self.a_smem_s = utils.sm100.make_smem_layout_a(qk_mma, self.mma_tiler, self.q_dtype, 1)
self.b_smem_s = utils.sm100.make_smem_layout_b(qk_mma, self.mma_tiler, self.b_dtype, 1)
self.v_smem_s = utils.sm100.make_smem_layout_b(pv_mma, self.pv_mma_tiler, self.b_dtype, 1)
self.p_tmem_s = utils.sm100.make_smem_layout_a(pv_mma, self.pv_mma_tiler, self.q_dtype, 1)
qk_thr = qk_mma.get_slice(0)
qk_acc_shape = qk_thr.partition_shape_C(self.qk_mma_tiler[:2])
tStS = qk_thr.make_fragment_C(qk_acc_shape)
s_cols = find_tmem_tensor_col_offset(tStS)
pv_thr = pv_mma.get_slice(0)
pv_acc_shape = pv_thr.partition_shape_C(self.pv_mma_tiler[:2])
tOtO = pv_thr.make_fragment_C(pv_acc_shape)
o_cols = find_tmem_tensor_col_offset(tOtO)
self.tilePlikeFP32 = self.qk_mma_tiler[1] // Float32.width * self.o_dtype.width
self.tmem_s0_offset = 0
self.tmem_p0_offset = 32
self.tmem_o0_offset = s_cols
tCtS_fake = qk_mma.make_fragment_C(cute.append(qk_acc_shape, self.num_acc_stage))
tCtO_fake = pv_mma.make_fragment_C(cute.append(pv_acc_shape, self.num_acc_stage))
self.num_tmem_alloc_cols = utils.get_num_tmem_alloc_cols([tCtS_fake, tCtO_fake], arch="sm_100")
print(f"[v28c] qk_mma_tiler={self.qk_mma_tiler} pv_mma_tiler={self.pv_mma_tiler}")
print(f"[v28c] s_cols={s_cols} o_cols={o_cols} num_tmem={self.num_tmem_alloc_cols}")
a_smem = cute.slice_(self.a_smem_s, (None, None, None, 0))
b_smem = cute.slice_(self.b_smem_s, (None, None, None, 0))
self.num_tma_load_bytes = (
cute.size_in_bytes(self.q_dtype, a_smem) + cute.size_in_bytes(self.b_dtype, b_smem)
) * cute.size(qk_mma.thr_id.shape)
@cute.jit
def __call__(self, q: cute.Tensor, k: cute.Tensor, v: cute.Tensor, stream: cuda.CUstream):
self.q_dtype = q.element_type; self.b_dtype = k.element_type
self.o_dtype = BFloat16; self.c_dtype = BFloat16
self.a_major = LayoutEnum.from_tensor(q).mma_major_mode()
self.b_major = LayoutEnum.from_tensor(k).mma_major_mode()
self.v_major = LayoutEnum.from_tensor(v).mma_major_mode()
qk_mma = utils.sm100.make_trivial_tiled_mma(
self.q_dtype, self.b_dtype, self.a_major, self.b_major,
self.qk_acc_dtype, self.cta_group, self.mma_tiler_mn, tcgen05.OperandSource.SMEM)
qk_inst_k = cute.size(qk_mma.shape_mnk, mode=[2])
qk_mma_tiler = (*self.mma_tiler_mn, qk_inst_k * 4)
pv_mma_tiler = (qk_mma_tiler[0], qk_mma_tiler[2], qk_mma_tiler[1])
pv_mma = utils.sm100.make_trivial_tiled_mma(
self.q_dtype, self.b_dtype, cute.nvgpu.OperandMajorMode.K, self.v_major,
self.qk_acc_dtype, self.cta_group, self.pv_mn, tcgen05.OperandSource.TMEM)
self._setup(qk_mma, pv_mma)
q_smem = cute.slice_(self.a_smem_s, (None, None, None, 0))
k_smem = cute.slice_(self.b_smem_s, (None, None, None, 0))
v_smem = cute.slice_(self.v_smem_s, (None, None, None, 0))
tma_q, tma_tq = cute.nvgpu.make_tiled_tma_atom_A(
utils.sm100.cluster_shape_to_tma_atom_A(self.cluster_shape_mn, qk_mma.thr_id),
q, q_smem, self.mma_tiler, qk_mma, self.cluster_layout_vmnk.shape)
tma_k, tma_tk = cute.nvgpu.make_tiled_tma_atom_B(
utils.sm100.cluster_shape_to_tma_atom_B(self.cluster_shape_mn, qk_mma.thr_id),
k, k_smem, self.mma_tiler, qk_mma, self.cluster_layout_vmnk.shape)
tma_v, tma_tv = cute.nvgpu.make_tiled_tma_atom_B(
utils.sm100.cluster_shape_to_tma_atom_B(self.cluster_shape_mn, pv_mma.thr_id),
v, v_smem, self.pv_mma_tiler, pv_mma, self.cluster_layout_vmnk.shape)
self._kernel(qk_mma, pv_mma, tma_q, tma_tq, tma_k, tma_tk, tma_v, tma_tv,
self.cluster_layout_vmnk, self.a_smem_s, self.b_smem_s, self.v_smem_s, self.p_tmem_s
).launch(grid=(1,1,1), block=[self.threads_per_cta,1,1], stream=stream)
@cute.kernel
def _kernel(self, qk_mma, pv_mma, tma_q, mQ, tma_k, mK, tma_v, mV,
cl_vmnk, a_smem_s, b_smem_s, v_smem_s, p_tmem_s):
warp_idx = cute.arch.make_warp_uniform(cute.arch.warp_idx())
tidx, _, _ = cute.arch.thread_idx()
use_2cta = cute.size(qk_mma.thr_id.shape) == 2
if warp_idx == self.tma_warp_id:
cpasync.prefetch_descriptor(tma_q); cpasync.prefetch_descriptor(tma_k)
cpasync.prefetch_descriptor(tma_v)
@cute.struct
class SS:
ab_bar: cute.struct.MemRange[cutlass.Int64, self.num_ab_stage * 2]
mma_si_bar: cute.struct.MemRange[cutlass.Int64, 2]
tmem_dealloc: cutlass.Int64
holding: cutlass.Int32
smem = utils.SmemAllocator(); st = smem.allocate(SS)
ab_p, ab_c = pipeline.PipelineTmaUmma.create(
barrier_storage=st.ab_bar.data_ptr(), num_stages=self.num_ab_stage,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread, 1),
tx_count=self.num_tma_load_bytes, cta_layout_vmnk=cl_vmnk, defer_sync=True
).make_participants()
mma_si_prod, mma_si_cons = pipeline.PipelineUmmaAsync.create(
barrier_storage=st.mma_si_bar.data_ptr(), num_stages=1,
producer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread),
consumer_group=pipeline.CooperativeGroup(pipeline.Agent.Thread, 32 * len(self.epilogue_warp_id)),
).make_participants()
tmem_bar = pipeline.NamedBarrier(barrier_id=self.tmem_alloc_sync_bar_id,
num_threads=32 * len((self.mma_warp_id, *self.epilogue_warp_id)))
tmem = utils.TmemAllocator(st.holding.ptr, barrier_for_retrieve=tmem_bar,
allocator_warp_id=self.epilogue_warp_id[0], is_two_cta=use_2cta,
two_cta_tmem_dealloc_mbar_ptr=st.tmem_dealloc.ptr)
pipeline.pipeline_init_arrive(cluster_shape_mn=cl_vmnk, is_relaxed=True)
sQ = smem.allocate_tensor(element_type=self.q_dtype, layout=a_smem_s.outer, byte_alignment=128, swizzle=a_smem_s.inner)
sK = smem.allocate_tensor(element_type=self.b_dtype, layout=b_smem_s.outer, byte_alignment=128, swizzle=b_smem_s.inner)
sV = smem.allocate_tensor(element_type=self.b_dtype, layout=v_smem_s.outer, byte_alignment=128, swizzle=v_smem_s.inner)
gQ = cute.local_tile(mQ, cute.slice_(self.qk_mma_tiler, (None,0,None)), (None,None,None))
gK = cute.local_tile(mK, cute.slice_(self.qk_mma_tiler, (0,None,None)), (None,None,None))
k_cnt = cute.size(gQ, mode=[3])
qk_thr = qk_mma.get_slice(0)
pv_thr = pv_mma.get_slice(0)
tCgQ = qk_thr.partition_A(gQ); tCgK = qk_thr.partition_B(gK)
a_lay = cute.make_layout(cute.slice_(cl_vmnk, (0,0,None,0)).shape)
tAsQ, tAgQ = cpasync.tma_partition(tma_q, 0, a_lay, cute.group_modes(sQ,0,3), cute.group_modes(tCgQ,0,3))
b_lay = cute.make_layout(cute.slice_(cl_vmnk, (0,None,0,0)).shape)
tBsK, tBgK = cpasync.tma_partition(tma_k, 0, b_lay, cute.group_modes(sK,0,3), cute.group_modes(tCgK,0,3))
tAgQ = tAgQ[(None,0,None,0)]; tBgK = tBgK[(None,0,None,0)]
gV = cute.local_tile(mV, cute.slice_(self.pv_mma_tiler, (0,None,None)), (None,None,None))
tCgV = pv_thr.partition_B(gV)
tVsV, tVgV = cpasync.tma_partition(tma_v, 0, b_lay, cute.group_modes(sV,0,3), cute.group_modes(tCgV,0,3))
tVgV = tVgV[(None,0,None,0)]
tCrQ = qk_mma.make_fragment_A(sQ); tCrK = qk_mma.make_fragment_B(sK)
tCrV = pv_mma.make_fragment_B(sV)
qk_acc_shape = qk_thr.partition_shape_C(self.qk_mma_tiler[:2])
tStS = qk_thr.make_fragment_C(qk_acc_shape)
tStS0 = cute.make_tensor(tStS.iterator + self.tmem_s0_offset, tStS.layout)
pv_acc_shape = pv_thr.partition_shape_C(self.pv_mma_tiler[:2])
tOtO = pv_thr.make_fragment_C(pv_acc_shape)
tOtO0 = cute.make_tensor(tOtO.iterator + self.tmem_o0_offset, tOtO.layout)
tP = cute.make_tensor(tStS.iterator, p_tmem_s.outer)
tOrP_base = pv_thr.make_fragment_A(tP)
tOrP = tOrP_base[(None, None, None, 0)]
tOrP0 = cute.make_tensor(
tOrP.iterator + self.qk_acc_dtype.width // self.q_dtype.width * self.tmem_p0_offset,
tOrP.layout)
pipeline.pipeline_init_wait(cluster_shape_mn=cl_vmnk)
# ===== TMA LOAD WARP =====
if warp_idx == self.tma_warp_id:
ab_p.reset(); peek = ab_p.try_acquire()
for kt in cutlass.range(k_cnt, unroll=1):
h = ab_p.acquire_and_advance(peek)
cute.copy(tma_q, tAgQ[(None,h.count)], tAsQ[(None,h.index)], tma_bar_ptr=h.barrier)
cute.copy(tma_k, tBgK[(None,h.count)], tBsK[(None,h.index)], tma_bar_ptr=h.barrier)
cute.copy(tma_v, tVgV[(None,h.count)], tVsV[(None,h.index)], tma_bar_ptr=h.barrier)
peek = cutlass.Boolean(1)
if h.count+1<k_cnt: peek = ab_p.try_acquire()
ab_p.tail()
# ===== MMA WARP =====
if warp_idx == self.mma_warp_id:
tmem.wait_for_alloc()
ab_c.reset(); peek = ab_c.try_wait()
s0_handle = mma_si_prod.acquire_and_advance()
qk_mma.set(tcgen05.Field.ACCUMULATE, False)
for kt in range(k_cnt):
h = ab_c.wait_and_advance(peek)
nblk = cute.size(tCrQ, mode=[2])
for kb in cutlass.range(nblk, unroll_full=True):
cute.gemm(qk_mma, tStS0, tCrQ[(None,None,kb,h.index)], tCrK[(None,None,kb,h.index)], tStS0)
qk_mma.set(tcgen05.Field.ACCUMULATE, True)
h.release(); peek = cutlass.Boolean(1)
if h.count+1<k_cnt: peek = ab_c.try_wait()
cute.arch.fence_view_async_tmem_store()
s0_handle.commit()
s0_handle = mma_si_prod.acquire_and_advance()
pv_mma.set(tcgen05.Field.ACCUMULATE, False)
tCrV_s = tCrV[(None, None, None, 0)]
num_kphases = cute.size(tOrP0, mode=[2])
for kphase_idx in cutlass.range(num_kphases, unroll_full=True):
pv_mma.set(tcgen05.Field.ACCUMULATE, kphase_idx != 0)
cute.gemm(pv_mma, tOtO0, tOrP0[(None,None,kphase_idx)], tCrV_s[(None,None,kphase_idx)], tOtO0)
cute.arch.fence_view_async_tmem_store()
if tidx == 128: print("[MMA] PV complete")
# ===== EPILOGUE WARPS (softmax only, no output store) =====
if warp_idx < self.mma_warp_id:
tmem.allocate(self.num_tmem_alloc_cols)
tmem.wait_for_alloc()
tmem_ptr = tmem.retrieve_ptr(self.qk_acc_dtype)
sfw_idx = tidx % (32 * len(self.epilogue_warp_id))
tmem_load_atom = cute.make_copy_atom(
tcgen05.copy.Ld32x32bOp(tcgen05.copy.Repetition(32)), self.qk_acc_dtype)
tiled_tmem_load = tcgen05.make_tmem_copy(tmem_load_atom, tStS0)
thr_load = tiled_tmem_load.get_slice(sfw_idx)
tTMEM_LOADtS = thr_load.partition_S(tStS0)
cS = cute.make_identity_tensor((self.qk_mma_tiler[0], self.qk_mma_tiler[1]))
tScS = qk_thr.partition_C(cS)
tTMEM_LOADcS = thr_load.partition_D(tScS)
tStS_P_layout = cute.composition(tStS.layout, cute.make_layout((128, self.tilePlikeFP32)))
tStS_P = cute.make_tensor(tStS.iterator + self.tmem_p0_offset, tStS_P_layout)
tmem_store_atom = cute.make_copy_atom(
tcgen05.copy.St32x32bOp(tcgen05.copy.Repetition(32)), self.qk_acc_dtype)
tiled_tmem_store = tcgen05.make_tmem_copy(tmem_store_atom, tStS_P)
thr_store = tiled_tmem_store.get_slice(sfw_idx)
tTMEM_STOREtS_x4 = thr_store.partition_D(tStS_P)
tScS_P_layout = cute.composition(tScS.layout, cute.make_layout((128, self.tilePlikeFP32)))
tScS_P = cute.make_tensor(tScS.iterator, tScS_P_layout)
tTMEM_STOREcS = thr_store.partition_S(tScS_P)
si_handle = mma_si_cons.wait_and_advance()
tTMEM_LOADrS = cute.make_rmem_tensor(tTMEM_LOADcS.shape, self.qk_acc_dtype)
cute.copy(tiled_tmem_load, tTMEM_LOADtS, tTMEM_LOADrS)
tTMEM_STORErS_x4 = cute.make_rmem_tensor(tTMEM_STOREcS.shape, self.qk_acc_dtype)
tTMEM_STORErS_x4_e = cute.make_tensor(
cute.recast_ptr(tTMEM_STORErS_x4.iterator, dtype=self.q_dtype),
tTMEM_LOADrS.layout)
frg_cnt = 4
frg_tile = cute.size(tTMEM_LOADrS) // frg_cnt
tTMEM_LOADrS_frg = cute.logical_divide(tTMEM_LOADrS, cute.make_layout(frg_tile))
tTMEM_STORErS_x4_e_frg = cute.logical_divide(
tTMEM_STORErS_x4_e, cute.make_layout(frg_tile))
for j in range(frg_cnt):
s_vec = tTMEM_LOADrS_frg[None, j].load()
tTMEM_STORErS_x4_e_frg[None, j].store(s_vec.to(self.q_dtype))
cute.copy(tiled_tmem_store, tTMEM_STORErS_x4, tTMEM_STOREtS_x4)
cute.arch.fence_view_async_tmem_store()
si_handle.release()
if tidx == 0: print("[EPI] Softmax complete")
# NO EPILOGUE STORE - just free tmem
tmem.relinquish_alloc_permit()
tmem.free(tmem_ptr)
def test(pv_mn, label):
torch.manual_seed(42)
m, n, head_dim = 128, 128, 64
q = torch.randn(m, head_dim, 1, dtype=torch.bfloat16, device='cuda')
k = torch.randn(n, head_dim, 1, dtype=torch.bfloat16, device='cuda')
v_base = torch.randn(head_dim, n, dtype=torch.bfloat16, device='cuda')
v = v_base.as_strided((head_dim, n), (1, head_dim)).unsqueeze(-1)
import cutlass.torch as ct
mQ = ct.from_dlpack(q).mark_layout_dynamic(leading_dim=ct.get_leading_dim(q))
mK = ct.from_dlpack(k).mark_layout_dynamic(leading_dim=ct.get_leading_dim(k))
mV = ct.from_dlpack(v).mark_layout_dynamic(leading_dim=ct.get_leading_dim(v))
stream = cuda.CUstream(torch.cuda.current_stream().cuda_stream)
kernel = StageBNoEpi(pv_mn=pv_mn)
print(f'Compiling {label}...', flush=True)
compiled = cute.compile(kernel, mQ, mK, mV, stream)
print(f'Running {label}...', flush=True)
compiled(mQ, mK, mV, stream)
torch.cuda.synchronize()
print(f'{label}: COMPLETE (no deadlock)')
if __name__ == '__main__':
test((128, 128), "PV(128,128)")
# test((128, 64), "PV(128,64)") # Skip if 128,128 hangs