Files
triton/python/examples/tutorials/mat_mul.py
2021-07-27 12:38:48 -07:00

134 lines
3.9 KiB
Python

import torch
import triton
class _dot(torch.autograd.Function):
src = """
__global__ void dot(TYPE *A __noalias __readonly __aligned(16),
TYPE *B __noalias __readonly __aligned(16),
TYPE *C __noalias __aligned(16),
float alpha,
int M __retune,
int N __retune,
int K __retune,
int lda __multipleof(8),
int ldb __multipleof(8),
int ldc __multipleof(8)) {
// prologue
int ridx = get_program_id(0);
int ridy = get_program_id(1);
int ridz = get_program_id(2);
int gridx = M / TM;
int gridy = N / TN;
int rid = ridx + ridy * gridx;
ridx = rid / gridy;
ridy = rid % gridy;
int rm[TM] = ridx * TM + 0 ... TM;
int rn[TN] = ridy * TN + 0 ... TN;
// reduction splitting
K = K / TZ;
int rk[TK] = ridz * K + 0 ... TK;
// pointers to operands
int offa[TM, TK] = rk[newaxis, :] * STRIDE_AK + rm[:, newaxis] * STRIDE_AM;
int offb[TK, TN] = rk[:, newaxis] * STRIDE_BK + rn[newaxis, :] * STRIDE_BN;
TYPE* pa[TM, TK] = A + offa;
TYPE* pb[TK, TN] = B + offb;
// prefetches operands
bool checka[TM, TK] = rk[newaxis, :] < K;
bool checkb[TK, TN] = rk[:, newaxis] < K;
TYPE a[TM, TK] = checka ? *pa : 0;
TYPE b[TK, TN] = checkb ? *pb : 0;
// reduction loop
float acc[TM, TN] = 0;
for(int k = K; k > 0; k -= TK){
acc += a @ b;
bool checka[TM, TK] = k > TK;
bool checkb[TK, TN] = k > TK;
pa += TK * STRIDE_AK;
pb += TK * STRIDE_BK;
a = *?(checka)pa;
b = *?(checkb)pb;
}
acc = acc * alpha;
TYPE c[TM, TN] = acc;
// epilogue
int rxm[TM] = get_program_id(0) * TM + 0 ... TM;
int rxn[TN] = get_program_id(1) * TN + 0 ... TN;
int offc[TM, TN] = rxm[:, newaxis] * ldc + rxn[newaxis, :];
TYPE* pc[TM, TN] = C + offc;
bool checkc[TM, TN] = (rxm[:, newaxis] < M) && (rxn[newaxis, :] < N);
#if (TZ==1)
*?(checkc) pc = c;
#else
// accumulate partial result using spin-locks
int *plock = locks + rid;
int *pcount = plock + get_num_programs(0) * get_num_programs(1);
for(int repeat = 1; repeat == 1; repeat = atomic_cas(plock, 0, 1));
int count = *pcount;
if(count == 0)
*?(checkc) pc = c;
else
*?(checkc) pc = c + *?(checkc)pc;
atomic_xchg(pcount, (count + 1) % TZ);
atomic_xchg(plock, 0);
#endif
}
"""
@staticmethod
def forward(ctx, a, b):
c = _dot._call(a,b)
return c
kernel = dict()
@staticmethod
def _call(a, b):
# create kernel if necessary
dtype = a.dtype
if dtype not in _dot.kernel:
defines = {
'TYPE' : dtype,
'STRIDE_AM': '1', 'STRIDE_AK': 'lda',
'STRIDE_BN': '1', 'STRIDE_BK': 'ldb',
'TM' : [64, 128],
'TN' : [64, 128],
'TK' : [8, 16],
'TZ' : [1]
}
_dot.kernel[dtype] = triton.kernel(_dot.src, num_warps=[4], defines=defines)
kernel = _dot.kernel[dtype]
# allocate output
M, K = a.shape
K, N = b.shape
c = triton.empty([M,N], dtype=dtype)
# enqueue
grid = lambda opt: [triton.cdiv(M, opt.d('TM')),
triton.cdiv(N, opt.d('TN'))]
time = kernel(a, b, c, 1., M, N, K,
a.stride(0), b.stride(0), c.stride(0),
grid=grid, bench=100)
print(2*M*N*K/(time*1e-6)*1e-9)
return c
dot = _dot.apply
torch.manual_seed(0)
M, N, K = 2048, 2048, 2048
a = torch.rand((M, K)).cuda()
b = torch.rand((K, N)).cuda()
#zc = torch.matmul(a,b)
zc_ = dot(a,b)
#print(torch.allclose(zc, zc_))