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Python

import torch
from tvm import tl
import tvm.tl.language as T
def matmul_splitk(M, N, K, blk_m, blk_n, block_K, split):
dtype = "float16"
accum_dtype = "float"
assert K % (block_K * split) == 0
KK = K // split
@T.prim_func
def main(A: T.Buffer((M, K), dtype), B: T.Buffer((K, N), dtype), C: T.Buffer((M, N), dtype)):
SplitC = T.alloc_buffer(
[split, (M + blk_m - 1) // blk_m * blk_m, (N + blk_n - 1) // blk_n * blk_n], dtype
)
with T.Kernel(T.ceildiv(N, blk_n), T.ceildiv(M, blk_m), split) as (bx, by, bz):
A_shared = T.alloc_shared((blk_m, block_K), dtype)
B_shared = T.alloc_shared((block_K, blk_n), dtype)
C_local = T.alloc_fragment((blk_m, blk_n), accum_dtype)
T.clear(C_local)
for k in T.Pipelined(K // (block_K * split), num_stages=3):
T.copy(A[by * blk_m, KK * bz + k * block_K], A_shared)
T.copy(B[KK * bz + k * block_K, bx * blk_n], B_shared)
T.gemm(A_shared, B_shared, C_local)
T.copy(
C_local,
SplitC[bz, by * blk_m : (by + 1) * blk_m, bx * blk_n : (bx + 1) * blk_n],
)
with T.Kernel(T.ceildiv(N, blk_n), T.ceildiv(M, blk_m)) as (bx, by):
acc = T.alloc_fragment((blk_m, blk_n), dtype)
T.clear(acc)
for k in range(split):
for i, j in T.Parallel(blk_m, blk_n):
acc[i, j] += SplitC[k, blk_m * by + i, blk_n * bx + j]
T.copy(acc, C[by * blk_m, bx * blk_n])
return main
def ref_program(A, B):
return A @ B
if __name__ == "__main__":
M, N, K, blk_m, blk_n, block_K, split = 8192, 8192, 8192, 128, 128, 32, 4
total_flops = 2 * M * N * K
program = matmul_splitk(M, N, K, blk_m, blk_n, block_K, split)
mod, params = tl.lower(program)
mod = tl.Profiler(mod, params, [2], tl.TensorSupplyType.Integer)
mod.assert_allclose(ref_program)
latency = mod.do_bench(ref_program, warmup=500)
print("{:.2f} ms".format(latency))
print("{:.2f} TFlops".format(total_flops / latency * 1e-9))
latency = mod.do_bench(mod.func)
print("{:.2f} ms".format(latency))
print("{:.2f} TFlops".format(total_flops / latency * 1e-9))