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tinygrad/extra/gemm_fragment.py
George HotzandGitHub d65ea465ed cleanup gemm fragment + add store unshard (#17313)
* cleanup gemm fragment + add store unshard

* multi

* fix
2026-07-30 20:53:28 -07:00

140 lines
6.6 KiB
Python

"""
tilelang-style matmul_relu written with tinygrad UOp APIs.
Reference tilelang kernel:
@tilelang.jit
def matmul_relu(A, B, block_M=64, block_N=64, block_K=64,
dtype=T.float16, accum_dtype=T.float32):
M, N, K = T.const('M, N, K')
C = T.empty([M, N], dtype)
with T.Kernel(T.ceildiv(N, block_N), T.ceildiv(M, block_M), threads=128) as (bx, by):
A_shared = T.alloc_shared((block_M, block_K), dtype)
B_shared = T.alloc_shared((block_K, block_N), dtype)
C_local = T.alloc_fragment((block_M, block_N), accum_dtype)
T.clear(C_local)
for ko in T.Pipelined(T.ceildiv(K, block_K), num_stages=3):
T.copy(A[by * block_M, ko * block_K], A_shared)
T.copy(B[ko * block_K, bx * block_N], B_shared)
T.gemm(A_shared, B_shared, C_local)
for i, j in T.Parallel(block_M, block_N):
C_local[i, j] = T.max(C_local[i, j], 0)
T.copy(C_local, C[by * block_M, bx * block_N])
return C
"""
from tinygrad.dtype import dtypes, AddrSpace, DType
from tinygrad.uop.ops import UOp, Ops, AxisType, KernelInfo
from tinygrad.helpers import cdiv, getenv
from tinygrad.tensor import Tensor
# ---------------------------------------------------------------------------
# tilelang builtins, expressed with tinygrad UOp APIs
# ---------------------------------------------------------------------------
def alloc_shared(shape:tuple[int, ...], dtype:DType, slot:int) -> UOp:
"""T.alloc_shared: one LOCAL buffer shared by all threads in the block."""
return UOp.placeholder(tuple(shape), dtype, slot, AddrSpace.LOCAL)
def alloc_fragment(shape:tuple[int, ...], dtype:DType, slot:int, axes:tuple[int, ...], rngs:tuple[UOp, ...]) -> UOp:
"""T.alloc_fragment: per-thread REG fragment + UNSHARD over the LOCAL thread grid."""
assert len(axes) == len(rngs)
assert all(tnum.op is Ops.RANGE and tnum.arg[-1] is AxisType.LOCAL for tnum in rngs), "fragments shard over LOCAL ranges"
by_axis = dict(zip(axes, rngs))
shard_shape = tuple(s // (int(by_axis[i].vmax)+1) if i in by_axis else s for i, s in enumerate(shape))
fragment = UOp.placeholder(shard_shape, dtype, slot, AddrSpace.REG)
return fragment.unshard(axes, rngs)
# ---------------------------------------------------------------------------
# GEMM kernel: C = relu(A @ B), float inputs (fp16 or fp32), fp32 fragment accumulator, no WMMA
# ---------------------------------------------------------------------------
# 64x64 output tile per block, 128 threads as an 8x16 grid; each thread owns an 8x4 fragment sub-tile
# (the 2-D per-thread layout tilelang infers for this GEMM). The 4 contiguous columns (TN=4) are what
# let codegen vectorize loads/stores to float4, matching tilelang's lowering exactly.
BLOCK_M = BLOCK_N = BLOCK_K = 64
TY = 8
TX = 16
THREADS = TY * TX
TM = BLOCK_M // TY # fragment rows per thread (8)
TN = BLOCK_N // TX # fragment columns per thread (4)
def matmul_relu_kernel(c:UOp, a:UOp, b:UOp) -> UOp:
"""C[M, N] = relu(A[M, K] @ B[K, N]) -- one 64x64 tile per block, locals + a 2-D fragment."""
M, K = a.shape
K2, N = b.shape
assert K == K2 and a.dtype == b.dtype == c.dtype and not dtypes.is_int(a.dtype)
assert not (K % BLOCK_K or M % BLOCK_M or N % BLOCK_N), "test sizes must be multiples of the block sizes"
# with T.Kernel(T.ceildiv(N, BLOCK_N), T.ceildiv(M, BLOCK_M), threads=128) as (bx, by):
bx = UOp.range(cdiv(N, BLOCK_N), 0, AxisType.GLOBAL)
by = UOp.range(cdiv(M, BLOCK_M), 1, AxisType.GLOBAL)
# 16*8 threads = 128 threads
tx = UOp.range(TX, 2, AxisType.LOCAL)
ty = UOp.range(TY, 3, AxisType.LOCAL)
# shared + fragment (regs)
A_shared = alloc_shared((BLOCK_M, BLOCK_K), a.dtype, 0)
B_shared = alloc_shared((BLOCK_K, BLOCK_N), b.dtype, 1)
C_local = alloc_fragment((TM, TY, TX, TN), dtypes.float32, 0, (1, 2), (ty, tx))
# zero out the regs to start. this is expanded by the devectorizer
C_local = C_local.after(C_local.store(0.0))
# for ko in T.Pipelined(T.ceildiv(K, BLOCK_K), num_stages=3):
ko = UOp.range(cdiv(K, BLOCK_K), 6, AxisType.LOOP)
# index the outer matrices
a = a.rearrange("(m bm) (k bk) -> m k bm bk", bm=BLOCK_M, bk=BLOCK_K)[by, ko]
b = b.rearrange("(k bk) (n bn) -> k n bk bn", bk=BLOCK_K, bn=BLOCK_N)[ko, bx]
c = c.rearrange("(m bm) (n bn) -> m n bm bn", bm=BLOCK_M, bn=BLOCK_N)[by, bx]
# T.copy: A_shared <- a, B_shared <- b
def with_threads(x:UOp): return x.rearrange("(tm ty) (tx tn) -> ty tx tm tn", tm=TM, tn=TN)[ty, tx]
A_shared = A_shared.after(with_threads(A_shared).store(with_threads(a)))
B_shared = B_shared.after(with_threads(B_shared).store(with_threads(b)))
# T.gemm(A_shared, B_shared, C_local), no WMMA
kk = UOp.range(BLOCK_K, 11, AxisType.LOOP)
ir = UOp.range(TM, 12, AxisType.LOOP)
jj = UOp.range(TN, 13, AxisType.UPCAST)
acc = C_local.after(kk)[ir, ty, tx, jj] + A_shared[ir*TM + ty, kk].cast(dtypes.float32) * B_shared[kk, tx*TN + jj].cast(dtypes.float32)
# closing the ko loop here too; codegen adds the barrier so no thread overwrites the tiles while others still read them
C_local = C_local[ir, ty, tx, jj].set(acc, end=(kk, ir, jj, ko))
# c <- C_local (with relu and cast): every thread stores its shard's sub-view of the output tile
c_st = c.reshape(C_local.shape).store(C_local.relu().cast(c.dtype))
# close the locals and globals
return c_st.end(tx, ty, bx, by).sink(arg=KernelInfo(name="matmul_relu", opts_to_apply=()))
# ---------------------------------------------------------------------------
# python wrapper: same signature as the tilelang function
# ---------------------------------------------------------------------------
def matmul_relu(a:Tensor, b:Tensor) -> Tensor:
"""C = relu(A @ B), fp16 in/out with an fp32 fragment accumulator."""
c = Tensor.empty(a.shape[0], b.shape[1], dtype=a.dtype, device=a.device)
return c.custom_kernel(a, b, fxn=matmul_relu_kernel)[0]
# ---------------------------------------------------------------------------
# test
# ---------------------------------------------------------------------------
if __name__ == "__main__":
from tinygrad import Device
assert Device[Device.DEFAULT].renderer.has_local, "this GPU-style kernel needs a backend with local memory (LOCAL ranges + barriers)"
M = K = N = getenv("N", 256) # 4x4 grid of 64x64 tiles, 4 K chunks
dtype_in = dtypes.half if getenv("HALF") else dtypes.float
a = Tensor.randn(M, K, dtype=dtype_in).contiguous()
b = Tensor.randn(K, N, dtype=dtype_in).contiguous()
ref = (a @ b).relu().realize()
for _ in range(10):
out = matmul_relu(a, b).realize()
import numpy as np
np.testing.assert_allclose(out.numpy(), ref.numpy(), atol=1e-1, rtol=1e-2)
print("matmul_relu passed!")