tensor alignment fix

This commit is contained in:
dxh 2025-03-07 10:58:37 +08:00
parent ba142b891a
commit 0b5d353dba
3 changed files with 23 additions and 92 deletions

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@ -2,6 +2,7 @@ import torch
from typing import Tuple
from .tuner import jit_tuner
from .config import config_cache
from .utils import get_num_sms, ceil_div, get_col_major_tma_aligned_tensor, get_m_alignment_for_contiguous_layout
# C++ code templates
@ -30,80 +31,6 @@ GemmType::run(out, rhs_scales, nullptr,
stream, num_sms, smem_size);
"""
def is_tma_multicast_legal(n: int, block_n: int, num_tma_multicast: int, num_sms: int) -> bool:
if num_tma_multicast == 1:
return True
return (n % (block_n * num_tma_multicast) == 0) and num_sms % num_tma_multicast == 0
def get_smem_size(num_stages: int, k: int, block_m: int, block_n: int, block_k: int = 128) -> int:
smem_d = block_m * block_n * 2
smem_a_per_stage = block_m * block_k
smem_scales_a_per_stage = block_m * 4
smem_b_per_stage = block_n * block_k
smem_scales_b = ceil_div(k, block_k) * 4
smem_barrier = num_stages * 8 * 2
smem_size = 0
smem_size += smem_d
smem_size += num_stages * smem_a_per_stage
smem_size += num_stages * smem_scales_a_per_stage
smem_size += num_stages * smem_b_per_stage
smem_size += ceil_div(smem_scales_b * (1 if block_k % block_n == 0 else 2), 8) * 8
smem_size += smem_barrier
return smem_size
def get_best_configs(m: int, n: int, k: int, num_groups: int, num_sms: int,
is_grouped_contiguous: bool = False) -> Tuple[int, int, int, int, int]:
if not is_grouped_contiguous:
# TODO: for some cases, smaller M block is better, add them into tuning space
block_ms = (64 if m <= 64 else 128, )
else:
block_ms = (get_m_alignment_for_contiguous_layout(), )
block_ns = tuple(range(16, 129, 8))
fix_wave_saturate = lambda x: num_sms if x == 0 else x
get_num_waves = lambda bm, bn: (ceil_div(ceil_div(m, bm) * ceil_div(n, bn) * num_groups, num_sms) if bm else None)
get_last_wave_util = lambda bm, bn: fix_wave_saturate((ceil_div(m, bm) * ceil_div(n, bn) * num_groups) % num_sms)
# Decide block sizes by waves
best_block_m, best_block_n = None, None
for block_m in block_ms:
for block_n in block_ns:
success = False
num_waves, best_num_waves = get_num_waves(block_m, block_n), get_num_waves(best_block_m, best_block_n)
if best_block_m is None or best_block_n is None:
success = True
elif num_waves < best_num_waves:
success = True
elif num_waves == best_num_waves:
# Check last wave utilization
util = get_last_wave_util(block_m, block_n)
best_util = get_last_wave_util(best_block_m, best_block_n)
success = util > best_util or (util == best_util and (block_m > best_block_m or (block_m == best_block_m and block_n < best_block_n)))
best_block_m, best_block_n = (block_m, block_n) if success else (best_block_m, best_block_n)
assert best_block_m is not None and best_block_n is not None
# Always pick the longest one
# NOTES: for double B scales, the best number of stages may be reduced
best_num_stages, best_smem_size, sm90_capacity = None, None, 232448
for num_stages in (6, 5, 4) if 128 % best_block_n != 0 else (8, 7, 6, 5, 4):
best_smem_size = get_smem_size(num_stages, k, best_block_m, best_block_n)
if best_smem_size <= sm90_capacity:
best_num_stages = num_stages
break
assert best_num_stages is not None
# Decide the number of TMA multicast
best_num_tma_multicast = 1
if m >= 1024 and is_tma_multicast_legal(n, best_block_n, 2, num_sms) and num_groups == 1:
best_num_tma_multicast = 2
return best_block_m, best_block_n, best_num_stages, best_num_tma_multicast, best_smem_size
def gemm_fp8_fp8_bf16_nt(lhs: Tuple[torch.Tensor, torch.Tensor],
rhs: Tuple[torch.Tensor, torch.Tensor],
out: torch.Tensor) -> None:
@ -151,7 +78,7 @@ def gemm_fp8_fp8_bf16_nt(lhs: Tuple[torch.Tensor, torch.Tensor],
# Auto-tuning with compilation
global includes, template
num_sms = get_num_sms()
block_m, block_n, num_stages, num_tma_multicast, smem_size = get_best_configs(m, n, k, 1, num_sms)
block_m, block_n, num_stages, num_tma_multicast, smem_size = config_cache.compute_and_cache(m, n, k, 1, num_sms)
args = (lhs, lhs_scales, rhs, rhs_scales, out, m, torch.cuda.current_stream(), num_sms, smem_size)
runtime = jit_tuner.compile_and_tune(
name='gemm_fp8_fp8_bf16_nt',

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@ -1,8 +1,9 @@
import torch
from typing import Tuple
from .gemm import get_best_configs
from .tuner import jit_tuner
from .config import config_cache
from .utils import get_col_major_tma_aligned_tensor, get_num_sms
# C++ code templates
@ -84,7 +85,7 @@ def m_grouped_gemm_fp8_fp8_bf16_nt_contiguous(lhs: Tuple[torch.Tensor, torch.Ten
# Auto-tuning with compilation
global includes, template
num_sms = get_num_sms()
block_m, block_n, num_stages, num_tma_multicast, smem_size = get_best_configs(m, n, k, 1, num_sms,
block_m, block_n, num_stages, num_tma_multicast, smem_size = config_cache.compute_and_cache(m, n, k, 1, num_sms,
is_grouped_contiguous=True)
args = (lhs, lhs_scales, rhs, rhs_scales, out,
m_indices, m, num_groups,
@ -158,7 +159,7 @@ def m_grouped_gemm_fp8_fp8_bf16_nt_masked(lhs: Tuple[torch.Tensor, torch.Tensor]
# Auto-tuning with compilation
global includes, template
num_sms = get_num_sms()
block_m, block_n, num_stages, num_tma_multicast, smem_size = get_best_configs(expected_m, n, k, num_groups, num_sms)
block_m, block_n, num_stages, num_tma_multicast, smem_size = config_cache.compute_and_cache(expected_m, n, k, num_groups, num_sms)
# Extra checks for TMA store
if num_groups > 1 and m > block_m:

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@ -88,19 +88,22 @@ def get_col_major_tma_aligned_tensor(x: torch.Tensor) -> torch.Tensor:
"""
# NOTES: for the extreme performance, you may rewrite/fuse this function in CUDA
assert x.dim() in (2, 3)
remove_dim = False
if x.dim() == 2:
x, remove_dim = x.unsqueeze(0), True
m, n = x.shape
aligned_m = get_tma_aligned_size(m, x.element_size())
if x.stride(0) == 1 and x.stride(1) == aligned_m:
return x
aligned_x = torch.transpose(torch.empty((n, aligned_m), device=x.device), 0, 1)
aligned_x[:m, :] = x
aligned_x = aligned_x[:m, :]
return aligned_x
elif x.dim() == 3:
b, m, n = x.shape
aligned_m = get_tma_aligned_size(m, x.element_size())
if x.stride(0) == aligned_m * n and x.stride(1) == 1 and x.stride(2) == aligned_m:
return x
aligned_x = torch.transpose(torch.empty((b, n, aligned_m), device=x.device), 1,2)
aligned_x[:, :m, :] = x
aligned_x = aligned_x[:, :m, :]
return aligned_x
b, m, n = x.shape
aligned_m = get_tma_aligned_size(m, x.element_size())
# The last kernel gives a column-major TMA aligned layout
if x.stride(0) == aligned_m * n and x.stride(1) == 1 and x.stride(2) == aligned_m:
return x.squeeze(0) if remove_dim else x
# Normal layout requires transposing
aligned_x = torch.transpose(torch.empty((b, n, aligned_m), device=x.device, dtype=x.dtype), 1, 2)
aligned_x[:, :m, :] = x
aligned_x = aligned_x[:, :m, :]
return aligned_x.squeeze(0) if remove_dim else aligned_x