Files
StarPilot/tinygrad_repo/extra/gemm/moe_routing.py
T
2026-10-20 03:55:45 +00:00

213 lines
10 KiB
Python

import functools, math, pathlib
from tinygrad import Tensor, dtypes
from tinygrad.helpers import getenv
from tinygrad.uop.ops import UOp, Ops, KernelInfo, AxisType
from tinygrad.renderer import Estimates
from tinygrad.runtime.support.compiler_amd import HIPCCCompiler
BLOCK_ROW = 256
@functools.cache
def _router_mfma_fwd(out:UOp, x:UOp, weight:UOp, bias:UOp, *, dname:str) -> UOp:
*lead, K = x.shape
M = math.prod(lead)
E = weight.shape[0]
threads = UOp.special(256, "lidx0")
workgroups = UOp.special((M + 63) // 64, "gidx0")
sink = UOp.sink(out.base, x.base, weight.base, bias.base, threads, workgroups,
arg=KernelInfo(f"moe_router_mfma_{M}_{K}_{E}", estimates=Estimates(ops=2*M*E*K, mem=(M*K+E*K+E)*2+M*E*4)))
amd = pathlib.Path(__file__).parent.parent/"thunder"/"amd"
src = (amd/"moe_router_mfma.cpp").read_text()
lib = HIPCCCompiler("gfx950", [f"-I{(amd/'include').as_posix()}", "-std=c++20", "-DKITTENS_CDNA4", "-DHIP_ENABLE_WARP_SYNC_BUILTINS",
f"-DROUTER_M={M}", f"-DROUTER_K={K}", f"-DROUTER_E={E}"]).compile_cached(src)
return UOp(Ops.PROGRAM, src=(sink, UOp(Ops.LINEAR, src=(*sink.src, sink)), UOp(Ops.SOURCE, arg=src), UOp(Ops.BINARY, arg=lib)))
def _router_mfma_bwd(gradient:UOp, kernel:UOp) -> tuple:
_, x_u, weight_u, bias_u = kernel.src[1:5]
x, weight, bias = (Tensor(u, device=u.device) for u in (x_u, weight_u, bias_u))
reference = x.float() @ weight.float().T + bias.float()
grad_x, grad_weight, grad_bias = reference.gradient(x, weight, bias, gradient=Tensor(gradient, device=x_u.device))
return None, grad_x.uop, grad_weight.uop, grad_bias.uop
def router_mfma(x:Tensor, weight:Tensor, bias:Tensor) -> Tensor:
assert x.ndim >= 2 and weight.ndim == 2 and bias.ndim == 1
K = x.shape[-1]
E = weight.shape[0]
assert weight.shape == (E, K) and bias.shape == (E,)
assert x.dtype == weight.dtype == bias.dtype == dtypes.bfloat16
assert E == 32 and K % 64 == 0
if isinstance(x.device, tuple):
assert x.uop.axis == 0, f"router MFMA requires axis-0 sharding, got axis={x.uop.axis}"
local_shape = x.uop.shard_shape
assert local_shape[-1] == K and math.prod(local_shape[:-1]) % 64 == 0, f"unsupported local router shape {local_shape}"
else:
assert math.prod(x.shape[:-1]) % 64 == 0
x, weight, bias = x.contiguous(), weight.contiguous(), bias.contiguous()
out = _sharded_invalids((*x.shape[:-1], E), dtypes.float32, x.device)
out, *_ = Tensor.custom_kernel(out, x, weight, bias,
fxn=functools.partial(_router_mfma_fwd, dname=str(x.device)), grad_fxn=_router_mfma_bwd)
return out
def _sharded_invalids(shape:tuple[int, ...], dtype, device) -> Tensor:
if isinstance(device, tuple):
per = Tensor.invalids(shape[0]//len(device), *shape[1:], dtype=dtype, device=device)
return Tensor(per.uop.unshard(0), device=device)
return Tensor.invalids(*shape, dtype=dtype, device=device)
def _atomic_add(device:str) -> str:
return "__hip_atomic_fetch_add({0}, {1}, __ATOMIC_RELAXED, __HIP_MEMORY_SCOPE_AGENT);" if device == "AMD" \
else "__atomic_fetch_add({0}, {1}, __ATOMIC_RELAXED);"
def _blk_for(D:int) -> int:
blk = 64
while D % blk: blk //= 2
return blk
def _kv_ranges(G, N, D, BLK):
g = UOp.range(G, 0)
m = UOp.range(N, 1)
jo = UOp.range(D // BLK, 2)
ji = UOp.range(BLK, 3, AxisType.LOCAL)
return g, m, jo * BLK + ji, jo, ji
def _ggather_fwd_kernel(out:UOp, table:UOp, idx:UOp) -> UOp:
G, M, D = out.shape
g, m, j, jo, ji = _kv_ranges(G, M, D, _blk_for(D))
row = idx.index(g, m).cast(dtypes.weakint)
val = table.index(g, row, j).load()
return out.index(g, m, j).store(val).end(g, m, jo, ji).sink(
arg=KernelInfo(name=f"ggather_fwd_{M}_{D}", opts_to_apply=()))
def _ggather_zero_kernel(out:UOp) -> UOp:
i = UOp.range(out.numel(), 0)
return out.flatten().index(i).store(UOp.const(0.0, out.dtype)).end(i).sink(arg=KernelInfo(name="ggather_zero"))
def _sharded_zeros(shape:tuple[int, ...], dtype, device) -> Tensor:
return Tensor.custom_kernel(_sharded_invalids(shape, dtype, device), fxn=_ggather_zero_kernel)[0]
def _ggather_bwd(gradient:UOp, kernel:UOp) -> tuple:
_, table_u, idx_u = kernel.src[1:4]
dev = table_u.device
device = (dev[0] if isinstance(dev, tuple) else dev).split(":")[0]
G, R, D = table_u.shape
gt = _sharded_zeros((G, R, D), dtypes.float32, dev)
go = Tensor(gradient, device=dev)
atomic_str = _atomic_add(device)
def _bwd_kernel(gtab:UOp, gout:UOp, idx:UOp) -> UOp:
Gk, M, Dk = gout.shape
g, m, j, jo, ji = _kv_ranges(Gk, M, Dk, _blk_for(Dk))
row = idx.index(g, m).cast(dtypes.weakint)
val = gout.index(g, m, j).load().cast(dtypes.float32)
atomic = UOp(Ops.CUSTOM, src=(gtab.index(g, row, j), val), arg=(atomic_str, dtypes.void))
return atomic.end(g, m, jo, ji).sink(arg=KernelInfo(name=f"ggather_bwd_{M}_{Dk}", opts_to_apply=()))
grad_table = Tensor.custom_kernel(gt, go, Tensor(idx_u, device=dev), fxn=_bwd_kernel)[0]
return (None, grad_table.cast(table_u.dtype).uop, None)
def grouped_gather_rows(table:Tensor, idx:Tensor, n_groups:int) -> Tensor:
G, R, D = table.shape
M = idx.shape[1]
out = _sharded_invalids((G, M, D), table.dtype, table.device)
return Tensor.custom_kernel(out, table, idx, fxn=_ggather_fwd_kernel, grad_fxn=_ggather_bwd)[0]
def _gscatter_fwd_kernel(out:UOp, src:UOp, idx:UOp) -> UOp:
G, M, D = out.shape
k = idx.shape[1] // src.shape[1]
g, m, j, jo, ji = _kv_ranges(G, idx.shape[1], D, _blk_for(D))
row = idx.index(g, m).cast(dtypes.weakint)
val = src.index(g, (m // k).cast(dtypes.weakint), j).load()
return out.index(g, row, j).store(val).end(g, m, jo, ji).sink(
arg=KernelInfo(name=f"gscatter_fwd_{idx.shape[1]}_{D}", opts_to_apply=()))
def _gscatter_bwd(gradient:UOp, kernel:UOp) -> tuple:
_, src_u, idx_u = kernel.src[1:4]
dev = src_u.device
G, T_l, D = src_u.shape
k = idx_u.shape[1] // T_l
if getenv("GGATHER_SUM_HIP", 0):
from extra.gptoss_kernels.gather_sum import gather_sum
assert k == 4
return None, gather_sum(Tensor(gradient), Tensor(idx_u)).uop, None
sel = grouped_gather_rows(Tensor(gradient, device=dev), Tensor(idx_u, device=dev), G)
# FP8 dispatch carries BF16 gradients back to the quantizer, not FP8-rounded gradients.
grad_dtype = dtypes.bfloat16 if src_u.dtype == dtypes.fp8e4m3 else src_u.dtype
return (None, sel.reshape(G, T_l, k, D).sum(2).cast(grad_dtype).uop, None)
def grouped_scatter_rows(src:Tensor, idx:Tensor, m_l:int) -> Tensor:
G, T_l, D = src.shape
zero = _sharded_zeros((G, m_l, D), src.dtype, src.device)
return Tensor.custom_kernel(zero, src, idx, fxn=_gscatter_fwd_kernel, grad_fxn=_gscatter_bwd)[0]
def m_max_for(t_local:int, experts_per_tok:int, n_experts:int) -> int:
return (-(-t_local * experts_per_tok // BLOCK_ROW) + n_experts) * BLOCK_ROW
class Routing:
def __init__(self, weights:Tensor, dest_row:Tensor, off:Tensor, m_l:int, n_groups:int, t_local:int,
topi:Tensor|None=None, counts:Tensor|None=None):
self.weights, self.dest_row = weights, dest_row
self.off = off
self.topi = topi
self.counts = counts
self.m_l, self.n_groups, self.t_local = m_l, n_groups, t_local
@property
def tile_e(self) -> Tensor:
G, E = self.off.shape[0], self.off.shape[1] - 1
tr = Tensor.arange(self.m_l // BLOCK_ROW, dtype=dtypes.int32).reshape(1, -1, 1) * BLOCK_ROW
tr = tr.shard(self.off.device) if isinstance(self.off.device, tuple) else tr.to(self.off.device)
return ((tr >= self.off[:, :E].reshape(G, 1, E)).sum(-1) - 1).cast(dtypes.int32).reshape(-1)
@property
def rows_e(self) -> Tensor:
return self.tile_e.reshape(-1, 1).expand(-1, BLOCK_ROW).reshape(-1)
def n_groups_of(t:Tensor) -> int:
return len(t.device) if isinstance(t.device, tuple) else 1
def route(logits:Tensor, experts_per_tok:int, n_experts:int) -> Routing:
T, E = logits.shape
k, G = experts_per_tok, n_groups_of(logits)
assert T % G == 0, f"tokens {T} must split across {G} devices"
T_l = T // G
if getenv("FUSED_ROUTER_TOPK", 0):
from extra.gptoss_kernels.router_topk import fused_router_topk
weights, topi = fused_router_topk(logits.reshape(G, T_l, E))
else:
topv, topi = logits.reshape(G, T_l, E).topk(k)
weights = topv.softmax(-1)
return route_topk(weights, topi, n_experts)
def route_topk(weights:Tensor, topi:Tensor, n_experts:int) -> Routing:
G, T_l, k = weights.shape
E, m_l = n_experts, m_max_for(T_l, k, n_experts)
m = topi.reshape(G, T_l * k).cast(dtypes.int32).one_hot(E).cast(dtypes.int32)
counts = m.sum(1)
pad = ((counts + (BLOCK_ROW - 1)) // BLOCK_ROW) * BLOCK_ROW
off = pad.cumsum(1).pad(((0, 0), (1, 0)))
dest_row = ((m.cumsum(1) + off[:, :E].reshape(G, 1, E)) * m).sum(-1).sub(1).cast(dtypes.int32)
return Routing(weights, dest_row, off, m_l, G, T_l, topi=topi, counts=counts)
def dispatch(x:Tensor, r:Routing) -> Tensor:
G, D = r.n_groups, x.shape[-1]
return grouped_scatter_rows(x.reshape(G, r.t_local, D), r.dest_row, r.m_l).reshape(G * r.m_l, D)
def dispatch_fp8(x:Tensor|tuple[Tensor, Tensor], r:Routing) -> tuple[Tensor, Tensor]:
from extra.gptoss_kernels.quantize_mxfp8 import quantize_mxfp8_fused_qe8
q, e8 = x if isinstance(x, tuple) else quantize_mxfp8_fused_qe8(x)
if getenv("DISPATCH_GATHER", 0):
from extra.gptoss_kernels.dispatch import inverse_rows, dispatch_gather
assert r.counts is not None
src_row = inverse_rows(r.dest_row, r.counts, r.off, r.m_l)
return tuple(dispatch_gather(t.reshape(r.n_groups, r.t_local, -1), r.dest_row, src_row) for t in (q, e8))
return dispatch(q, r), dispatch(e8, r)
def combine(y:Tensor, r:Routing, n_tokens:int, experts_per_tok:int) -> Tensor:
G, D, k = r.n_groups, y.shape[-1], experts_per_tok
if getenv("FUSED_COMBINE", 0):
from extra.gptoss_kernels.combine import fused_combine
assert k == 4
return fused_combine(y.reshape(G, r.m_l, D), r.dest_row, r.weights.reshape(G, r.t_local, k)).reshape(n_tokens, D)
sel = grouped_gather_rows(y.reshape(G, r.m_l, D), r.dest_row, G).reshape(G, r.t_local, k, D)
return (sel * r.weights.reshape(G, r.t_local, k, 1).cast(sel.dtype)).sum(2).reshape(n_tokens, D).cast(y.dtype)