Files
tinygrad/extra/gemm/cdna_asm_gemm.py
qazalandGitHub 07f7383d29 llama: remove unused bf16 assembly gemm (#16859)
* only hk bf16 gemm

* rm asm gemm

* more cleanup

* half isn't supported in asm gemm anymore

* more test edits

* unused

* remove TestMagicGu

* uop gemm is still tested

* minimal diff
2026-07-04 18:41:54 +09:00

355 lines
20 KiB
Python

import atexit, functools, pathlib
from tinygrad import Tensor, Device, dtypes
from tinygrad.uop.ops import UOp, Ops, KernelInfo, AxisType
from tinygrad.renderer import Estimates
from tinygrad.helpers import getenv, all_same, DEBUG
from tinygrad.runtime.support.compiler_amd import HIPCCCompiler
from examples.mlperf.models.flat_llama import FP8_DTYPE, quantize_fp8
TILE_M, TILE_N, TILE_K = 256, 256, 64
# ** FP8 GEMM custom kernel
@functools.cache
def custom_hk_fp8_gemm(C:UOp, A:UOp, B:UOp, *args:UOp, dname:str, scale_mode:int=3) -> UOp:
# scale_mode: 0=no scale, 1=x only, 2=w only, 3=both
n_scales = (1 if scale_mode & 1 else 0) + (1 if scale_mode & 2 else 0) + (1 if scale_mode & 4 else 0)
scales, extra = args[:n_scales], args[n_scales:]
M, K = A.shape[0]*A.shape[1], A.shape[2]
N, K2 = B.shape[(1 if B.ndim == 3 else 0):]
assert K == K2, f"{A.shape} {B.shape}"
block_size = 256
threads = UOp.special(64 * 8, "lidx0")
workgroups = UOp.special((M // block_size) * (N // block_size), "gidx0")
sink_inputs = (C.base, A.base, B.base) + tuple(s.base for s in scales) + (threads, workgroups)
sink = UOp.sink(*sink_inputs,
arg=KernelInfo(f"hk_fp8_gemm_{M}_{N}_{K}", estimates=Estimates(ops=2*M*N*K, mem=(M*K+N*K)*A.dtype.itemsize+M*N*C.dtype.itemsize)))
kittens_path = pathlib.Path(__file__).parent.parent/"thunder"/"amd"
src = (kittens_path/"gemm_fp8.cpp").read_text()
lib = HIPCCCompiler("gfx950", [f"-I{(kittens_path/'include').as_posix()}", "-std=c++20", "-DKITTENS_CDNA4", "-ffast-math",
"-DHIP_ENABLE_WARP_SYNC_BUILTINS", f"-DGEMM_M={M}", f"-DGEMM_N={N}", f"-DGEMM_K={K}",
f"-DSCALE_MODE={scale_mode}"]).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)))
# ** MXFP8 GEMM custom kernel
@functools.cache
def custom_hk_mxfp8_gemm(C:UOp, A:UOp, B:UOp, scale_A:UOp, scale_B:UOp, *extra:UOp, dname:str) -> UOp:
# mxfp8 block-scaled gemm: A(M,K) @ B(N,K).T, e8m0 1x32 microscales packed (k_iters,dim) uint32
M, K = A.shape[0]*A.shape[1], A.shape[2]
N, K2 = B.shape[(1 if B.ndim == 3 else 0):]
assert K == K2, f"{A.shape} {B.shape}"
block_size = 256
threads = UOp.special(64 * 8, "lidx0")
workgroups = UOp.special((M // block_size) * (N // block_size), "gidx0")
e_a = extra[0].base if len(extra) >= 1 else scale_A.base
e_b = extra[1].base if len(extra) >= 2 else scale_B.base
sink_inputs = (C.base, A.base, B.base, scale_A.base, scale_B.base, e_a, e_b, threads, workgroups)
sink = UOp.sink(*sink_inputs,
arg=KernelInfo(f"hk_mxfp8_gemm_{M}_{N}_{K}", estimates=Estimates(ops=2*M*N*K, mem=(M*K+N*K)*A.dtype.itemsize+M*N*C.dtype.itemsize)))
kittens_path = pathlib.Path(__file__).parent.parent/"thunder"/"amd"
src = (kittens_path/"gemm_mxfp8.cpp").read_text()
lib = HIPCCCompiler("gfx950", [f"-I{(kittens_path/'include').as_posix()}", "-std=c++20", "-DKITTENS_CDNA4", "-ffast-math",
"-DHIP_ENABLE_WARP_SYNC_BUILTINS", f"-DGEMM_M={M}", f"-DGEMM_N={N}", f"-DGEMM_K={K}"]).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 quantize_mxfp8(x:Tensor) -> tuple[Tensor, Tensor, Tensor]:
# 1x32 block scaling along the last axis
*batch, K = x.shape
scale_K = K // 32
amax = x.detach().float().reshape(*batch, scale_K, 32).abs().max(axis=-1)
e8 = (amax.maximum(1e-38).log2().floor() + 127).clamp(0, 254).cast(dtypes.uint8)
qscale = (127.0 - e8.cast(dtypes.float32)).exp2().reshape(*batch, scale_K, 1).expand(*batch, scale_K, 32).reshape(*batch, K)
x_scaled = x.float() * qscale
x_clamped = x_scaled + (x_scaled.detach().clamp(-448.0, 448.0) - x_scaled.detach()) # STE
return x_clamped.cast(FP8_DTYPE), e8, (mx_pack(e8) if len(batch) == 1 else None)
def mx_pack(e8:Tensor) -> Tensor:
rows, scale_K = e8.shape
return e8.reshape(rows, scale_K // 4, 4).bitcast(dtypes.uint32).reshape(rows, scale_K // 4).permute(1, 0).contiguous()
def _mx_block_scale(e8:Tensor) -> Tensor:
# dequant scale 2^(e8-127) broadcast back to element shape
rows, scale_K = e8.shape
return (e8.cast(dtypes.float32) - 127.0).exp2().reshape(rows, scale_K, 1).expand(rows, scale_K, 32).reshape(rows, scale_K*32)
counters = {"used":0, "todos":[]}
def todo(msg:str) -> bool: counters["todos"].append(msg); return False
def _asm_gemm_report():
print(f'asm_gemm: {counters["used"]} used, {len(counters["todos"])} not used')
if DEBUG >= 2 and counters["todos"]:
from collections import Counter
for msg, cnt in Counter(counters["todos"]).most_common(): print(f' {cnt:3d}x {msg}')
atexit.register(_asm_gemm_report)
def can_use_asm_gemm(a:Tensor, b:Tensor) -> bool:
if a.dtype != b.dtype: return todo(f"dtypes must match {a.dtype} != {b.dtype}")
if a.dtype not in {dtypes.bfloat16, dtypes.float16, FP8_DTYPE}: return todo(f"only bfloat16/float16/fp8, got {a.dtype}")
batch, M, K = (1, *a.shape) if a.ndim == 2 else a.shape
N = b.shape[1]
if isinstance(a.device, tuple):
if a.ndim == 2 and a.uop.axis == 0 and b.uop.axis is None: M //= len(a.device)
elif a.ndim == 2 and a.uop.axis == 1 and b.uop.axis == 0: K //= len(a.device)
elif a.ndim == 2 and a.uop.axis is None and b.uop.axis == 1: N //= len(a.device)
elif a.ndim == 3 and a.uop.axis == 0 and b.uop.axis is None: batch //= len(a.device)
elif a.ndim == 3 and a.uop.axis is None and b.uop.axis == 1: N //= len(a.device)
elif a.ndim == 3 and a.uop.axis == 2 and b.uop.axis == 0: K //= len(a.device)
else: return todo(f"sharding mismatch a.ndim={a.ndim} a.uop.axis={a.uop.axis} b.uop.axis={b.uop.axis}")
dname = a.device[0]
else: dname = a.device
arch = Device[dname].renderer.target.arch
if batch not in {1, 2}: return todo(f"GEMM batch size {batch}")
if (M % TILE_M != 0 or N % TILE_N != 0 or K % TILE_K != 0) and arch == "gfx950":
return todo(f"GEMM shape ({M},{N},{K}) not a multiple of ({TILE_M},{TILE_N},{TILE_K})")
return True
# ** UOp gemm to test Tensor.custom_kernel multi and backward correctness on non cdna4
# note: this can be removed after we have GEMM on mixins
def custom_uop_gemm(C:UOp, A:UOp, B:UOp) -> UOp:
M, K = A.shape[0]*A.shape[1], A.shape[2]
K2, N = B.shape[(1 if B.ndim == 3 else 0):]
assert K == K2
m = UOp.range(M, 1, AxisType.LOOP)
n = UOp.range(N, 2, AxisType.LOOP)
k = UOp.range(K, 0, AxisType.REDUCE)
mul = (A.flatten().index((m*UOp.const(dtypes.weakint, K)+k))*
B.flatten().index((k*UOp.const(dtypes.weakint, N)+n))).cast(dtypes.float32)
red = mul.reduce(k, arg=Ops.ADD, dtype=dtypes.float32).cast(C.dtype.base)
store = C.flatten().index((m*UOp.const(dtypes.weakint, N)+n), ptr=True).store(red).end(m, n)
return store.sink(arg=KernelInfo(name=f'uop_gemm_{M}_{N}_{K}'))
# ** bf16 A @ B.T kernel in C
@functools.cache
def custom_hk_bf16_gemm(C:UOp, A:UOp, B:UOp, *args:UOp, dname:str) -> UOp:
M, K = A.shape[0]*A.shape[1], A.shape[2]
N, K2 = B.shape[(1 if B.ndim == 3 else 0):]
assert K == K2, f"{A.shape} {B.shape}"
block_m, block_n, block_k, num_warps = 256, 256, 64, 8
assert M % block_m == 0 and N % block_n == 0 and K % block_k == 0, f"invalid bf16 tile {(block_m, block_n, block_k)} for {(M, N, K)}"
threads = UOp.special(64 * num_warps, "lidx0")
workgroups = UOp.special((M // block_m) * (N // block_n), "gidx0")
b_extra = args[0].base if len(args) >= 1 else B.base
sink = UOp.sink(C.base, A.base, B.base, b_extra, threads, workgroups,
arg=KernelInfo(f"hk_bf16_gemm_{M}_{N}_{K}", estimates=Estimates(ops=2*M*N*K, mem=(M*K+N*K+M*N)*A.dtype.itemsize)))
kittens_path = pathlib.Path(__file__).parent.parent/"thunder"/"amd"
src = (kittens_path/"gemm_bf16.cpp").read_text()
lib = HIPCCCompiler("gfx950", [f"-I{(kittens_path/'include').as_posix()}", "-std=c++20", "-DKITTENS_CDNA4", "-ffast-math",
"-DHIP_ENABLE_WARP_SYNC_BUILTINS", f"-DGEMM_M={M}", f"-DGEMM_N={N}", f"-DGEMM_K={K}"]).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)))
@functools.cache
def custom_hk_bf16_atb_gemm(C:UOp, A:UOp, B:UOp, dname:str) -> UOp:
K, M = A.shape[0]*A.shape[1], A.shape[2]
K2, N = B.shape[0]*B.shape[1], B.shape[2]
assert K == K2, f"{A.shape} {B.shape}"
block_m, block_n, block_k, num_warps = 256, 256, 64, 8
assert M % block_m == 0 and N % block_n == 0 and K % block_k == 0, f"invalid bf16 atb tile {(block_m, block_n, block_k)} for {(M, N, K)}"
threads = UOp.special(64 * num_warps, "lidx0")
workgroups = UOp.special((M // block_m) * (N // block_n), "gidx0")
sink = UOp.sink(C.base, A.base, B.base, threads, workgroups,
arg=KernelInfo(f"hk_bf16_atb_gemm_{M}_{N}_{K}", estimates=Estimates(ops=2*M*N*K, mem=(M*K+N*K+M*N)*A.dtype.itemsize)))
kittens_path = pathlib.Path(__file__).parent.parent/"thunder"/"amd"
src = (kittens_path/"gemm_bf16_atb.cpp").read_text()
lib = HIPCCCompiler("gfx950", [f"-I{(kittens_path/'include').as_posix()}", "-std=c++20", "-DKITTENS_CDNA4", "-ffast-math",
"-DHIP_ENABLE_WARP_SYNC_BUILTINS", f"-DGEMM_M={M}", f"-DGEMM_N={N}", f"-DGEMM_K={K}"]).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 hk_bf16_atb_gemm(a:Tensor, b:Tensor) -> Tensor:
assert a.dtype == b.dtype == dtypes.bfloat16, f"expected bf16, got {a.dtype} {b.dtype}"
assert a.ndim == b.ndim == 3 and a.shape[:2] == b.shape[:2], f"{a.shape} {b.shape}"
batch, rows, M = a.shape
N = b.shape[2]
assert M % TILE_M == 0 and N % TILE_N == 0 and (batch * rows) % TILE_K == 0, \
f"atb shape {a.shape} {b.shape} must produce (M,N,K) multiples of ({TILE_M},{TILE_N},{TILE_K})"
is_multi = isinstance(a.device, tuple)
reduce_out = False
if is_multi:
ndev = len(a.device)
if a.uop.axis in (0, 1) or b.uop.axis in (0, 1): inv, out_axis, reduce_out = Tensor.invalids(1, M, N, dtype=a.dtype, device=a.device), 0, True
elif b.uop.axis == 2: inv, out_axis = Tensor.invalids(1, M, N // ndev, dtype=a.dtype, device=a.device), 2
elif a.uop.axis == 2: inv, out_axis = Tensor.invalids(1, M // ndev, N, dtype=a.dtype, device=a.device), 1
else: inv, out_axis, reduce_out = Tensor.invalids(1, M, N, dtype=a.dtype, device=a.device), 0, True
out = Tensor(inv.uop.multi(out_axis), device=a.device)
dname = a.device[0]
else:
out = Tensor.invalids(1, M, N, dtype=a.dtype, device=a.device)
dname = a.device
dname = dname.split(":")[0]
out = Tensor.custom_kernel(out, a, b, fxn=functools.partial(custom_hk_bf16_atb_gemm, dname=dname))[0]
if reduce_out: out = out.sum(0)
return out.squeeze(0) if out.ndim == 3 else out
# ** backward gemm, might use the asm gemm
def custom_gemm_bw(gradient:UOp, kernel:UOp, n_scales:int=2, has_grad_amax:bool=False, has_w_post:bool=False):
inputs = kernel.src[1:]
if inputs[1].dtype == FP8_DTYPE:
out, a, b = inputs[:3]
i = 3
s_x = inputs[i]; i += 1
has_w = n_scales >= 2
s_w = inputs[i] if has_w else None; i += has_w
s_g = inputs[i] if n_scales == 3 else None; i += (n_scales == 3)
grad_amax_state = inputs[i] if has_grad_amax else None; i += has_grad_amax
w_post = inputs[i] if has_w_post else None
a_t, b_t, g_t = Tensor(a, device=a.device), Tensor(b, device=a.device), Tensor(gradient, device=a.device)
s_x_t = Tensor(s_x, device=a.device)
s_w_t = Tensor(s_w, device=a.device) if has_w else None
s_g_t = Tensor(s_g, device=a.device) if s_g is not None else None
w_post_t = Tensor(w_post, device=a.device) if has_w_post else None
g_t = g_t[:a.shape[0]]
from extra.llama_kernels.cast_amax import _grad_fp8_mailbox
from extra.llama_kernels.quantize_fp8_delayed import quantize_fp8_delayed
gbase = gradient.base if hasattr(gradient, "base") else gradient
mailbox_entry = _grad_fp8_mailbox.pop(gbase, None) or _grad_fp8_mailbox.pop(gradient, None)
if mailbox_entry is not None:
g_fp8_u, inv_scale_u = mailbox_entry
g_fp8 = Tensor(g_fp8_u, device=a.device)[:a.shape[0]]
g_scale = Tensor(inv_scale_u, device=a.device)
else:
assert grad_amax_state is not None, "fp8 matmul bwd needs either a mailbox entry or a grad_amax_state"
if getenv("CURRENT_GRAD_SCALE", 0):
g_fp8, g_scale, _ = quantize_fp8(g_t, amax_state=None)
elif getenv("FUSED_GRAD_QUANTIZE", 0):
g_fp8, g_scale, _, store_effect = quantize_fp8_delayed(g_t, Tensor(grad_amax_state, device=a.device))
assert g_fp8.uop.op is Ops.AFTER, f"expected AFTER, got {g_fp8.uop.op}"
g_fp8 = Tensor(g_fp8.uop.replace(src=g_fp8.uop.src + (store_effect,)), device=a.device)
else:
grad_amax_t = Tensor(grad_amax_state, device=a.device)
g_fp8, g_scale, new_grad_amax = quantize_fp8(g_t, amax_state=grad_amax_t)
store_effect = grad_amax_state.store(new_grad_amax.uop)
g_fp8 = Tensor(g_fp8.contiguous().uop.after(store_effect), device=a.device)
# dgrad: uses g_scale * x_scale * w_scale (only when scalar)
if s_g_t is not None: g_scale = g_scale * s_g_t
grad_a = asm_gemm(g_fp8, b_t, x_scale=s_x_t, w_scale=s_w_t, g_scale=g_scale) if has_w else asm_gemm(g_fp8, b_t, x_scale=s_x_t, w_scale=g_scale)
# wgrad: no w_scale
g_fp8_T = g_fp8.permute(2, 0, 1).reshape(g_t.shape[-1], -1)
grad_b = asm_gemm(g_fp8_T, a_t.reshape(-1, a_t.shape[-1]), x_scale=s_x_t, w_scale=g_scale)
# wgrad: rescale if not scalar
if w_post_t is not None:
grad_b = grad_b / w_post_t.reshape(*w_post_t.shape, *([1]*(grad_b.ndim - w_post_t.ndim)))
# one None per input: (out, a, b, x_scale[, w_scale][, grad_amax][, w_post_scale])
ret = (None, grad_a.uop, grad_b.uop) + tuple(None for _ in inputs[3:])
return ret
else:
hk_bf16 = len(inputs) == 4 and inputs[1].dtype == dtypes.bfloat16
if hk_bf16:
out, a, b_t, b = inputs
assert all_same([gradient.device, a.device, b_t.device, b.device, out.device])
else:
assert len(inputs) == 3, f"regular gemm must have exactly 3 sources, got: {len(inputs)}"
out, a, b = inputs
assert all_same([gradient.device, a.device, b.device, out.device])
a_t, b_t, g_t = Tensor(a, device=a.device), Tensor(b, device=a.device), Tensor(gradient, device=a.device)
g_t = g_t[:a.shape[0]]
if hk_bf16 and g_t.dtype != b_t.dtype: g_t = g_t.cast(b_t.dtype)
if can_use_asm_gemm(g_t, b_t.T): grad_a = asm_gemm(g_t, b_t.T).uop
else: grad_a = (g_t @ b_t.T).uop
if hk_bf16:
grad_b = hk_bf16_atb_gemm(a_t, g_t).uop
else:
a_t_flat, g_t_flat = a_t.permute(2, 0, 1).reshape(a_t.shape[2], -1), g_t.reshape(-1, g_t.shape[-1])
if can_use_asm_gemm(a_t_flat, g_t_flat): grad_b = asm_gemm(a_t_flat, g_t_flat).uop
else: grad_b = (a_t_flat @ g_t_flat).uop
# hk_bf16 uses b.T, writes gradients only for a and b
return (None, grad_a, None, grad_b) if hk_bf16 else (None, grad_a, grad_b)
# ** mxfp8 gemm backward
def custom_mx_gemm_bw(gradient:UOp, kernel:UOp, has_w_post:bool, w_stored:bool=False):
inputs = kernel.src[1:] # (out, a_q, b_q, a_si, b_si, a_e8, b_e8, [w_post])
aq, bq = Tensor(inputs[1], device=inputs[1].device), Tensor(inputs[2], device=inputs[2].device)
ae8, be8 = Tensor(inputs[5], device=inputs[5].device), Tensor(inputs[6], device=inputs[6].device)
wp = Tensor(inputs[7], device=inputs[7].device) if has_w_post else None
a_phys = (aq.reshape(-1, aq.shape[-1]).cast(dtypes.bfloat16) * _mx_block_scale(ae8)).cast(dtypes.bfloat16)
b_phys = (bq.cast(dtypes.bfloat16) * _mx_block_scale(be8)).cast(dtypes.bfloat16)
g = Tensor(gradient, device=aq.device)[:aq.shape[0]].reshape(aq.shape[0]*aq.shape[1], bq.shape[0]).cast(dtypes.bfloat16)
grad_a = asm_gemm(g, b_phys, mx=True)
grad_b = asm_gemm(g.T, a_phys, mx=True, a_pretranspose=g)
grad_a = (grad_a * _mx_block_scale(ae8)).reshape(aq.shape)
if not w_stored: grad_b = grad_b * _mx_block_scale(be8)
if wp is not None: grad_b = grad_b / wp.reshape(-1, 1)
return (None, grad_a.uop, grad_b.uop) + tuple(None for _ in inputs[3:])
# ** main gemm function
def asm_gemm(a:Tensor, b:Tensor, x_scale:Tensor|None=None, w_scale:Tensor|None=None, grad_amax_state:Tensor|None=None,
w_post_scale:Tensor|None=None, mx:bool=False, mx_scales:tuple|None=None, mx_w_stored:bool=False, g_scale:Tensor|None=None,
a_pretranspose:Tensor|None=None) -> Tensor:
assert can_use_asm_gemm(a, b), f"{counters['todos'][-1]}"
counters["used"] += 1
unfold_batch = a.ndim == 3 and isinstance(a.device, tuple) and a.uop.axis == 2 and b.uop.axis == 0
if unfold_batch:
orig_batch = a.shape[0]
a = a.reshape(a.shape[0]*a.shape[1], a.shape[2])
squeeze = a.ndim == 2
if squeeze: a = a.unsqueeze(0)
out_dtype = dtypes.bfloat16 if a.dtype == FP8_DTYPE else a.dtype
batch, M, K = a.shape
N = b.shape[1]
is_multi = isinstance(a.device, tuple)
if (k_sharded:=is_multi and a.uop.axis == 2): K //= len(a.device)
if (m_sharded:=is_multi and a.uop.axis == 1): M //= len(a.device)
n_sharded = is_multi and b.uop.axis == 1
if is_multi:
if n_sharded:
out = Tensor(Tensor.invalids(batch, M, N//len(a.device), dtype=out_dtype, device=a.device).uop.multi(2), device=a.device)
elif m_sharded:
out = Tensor(Tensor.invalids(batch, M, N, dtype=out_dtype, device=a.device).uop.multi(1), device=a.device)
else:
out = Tensor(Tensor.invalids(batch//len(a.device) if a.uop.axis==0 else batch, M, N, dtype=out_dtype, device=a.device).uop.multi(0),
device=a.device)
else:
out = Tensor.invalids(batch, M, N, dtype=out_dtype, device=a.device)
renderer = Device[dname:=(a.device[0] if is_multi else a.device)].renderer
dname, arch = dname.split(":")[0], renderer.target.arch
if arch.startswith("gfx950") and getenv("USE_ASM", 1):
if mx:
# mxfp8 1x32 block scaling
if mx_scales is not None:
a_si, a_e8, b_si, b_e8 = mx_scales
a_q, b_q = a.reshape(-1, a.shape[-1]), b.T
elif (a_pretranspose is not None and getenv("FUSED_GRAD_QUANTIZE", 0) and a_pretranspose.dtype == dtypes.bfloat16
and a_pretranspose.shape[0] % 32 == 0 and a_pretranspose.shape[1] % 256 == 0):
from extra.llama_kernels.transpose_quantize_mxfp8 import transpose_quantize_mxfp8
a_q, a_e8, a_si = transpose_quantize_mxfp8(a_pretranspose)
b_q, b_e8, b_si = quantize_mxfp8(b.T)
else:
a_q, a_e8, a_si = quantize_mxfp8(a.reshape(-1, a.shape[-1]))
b_q, b_e8, b_si = quantize_mxfp8(b.T)
has_w_post = w_post_scale is not None
fxn = functools.partial(custom_hk_mxfp8_gemm, dname=dname)
grad_fxn = functools.partial(custom_mx_gemm_bw, has_w_post=has_w_post, w_stored=mx_w_stored)
extra = [w_post_scale] if w_post_scale is not None else []
out = Tensor.custom_kernel(out, a_q.reshape(a.shape), b_q, a_si, b_si, a_e8, b_e8, *extra, fxn=fxn, grad_fxn=grad_fxn)[0]
# fp8 gemm computes [email protected], kernel multiplies output by x_scale * w_scale before bf16 store
elif a.dtype == FP8_DTYPE:
scales = tuple(s for s in (x_scale, w_scale, g_scale) if s is not None)
scale_mode = (1 if x_scale is not None else 0) | (2 if w_scale is not None else 0) | (4 if g_scale is not None else 0)
extra = ([grad_amax_state] if grad_amax_state is not None else []) + ([w_post_scale] if w_post_scale is not None else [])
fxn = functools.partial(custom_hk_fp8_gemm, dname=dname, scale_mode=scale_mode)
bw = functools.partial(custom_gemm_bw, n_scales=len(scales), has_grad_amax=grad_amax_state is not None, has_w_post=w_post_scale is not None)
out = Tensor.custom_kernel(out, a, b.T, *scales, *extra, fxn=fxn, grad_fxn=bw)[0]
elif a.dtype == dtypes.bfloat16:
out = Tensor.custom_kernel(out, a, b.T, b, fxn=functools.partial(custom_hk_bf16_gemm, dname=dname), grad_fxn=custom_gemm_bw)[0]
else:
out = Tensor.custom_kernel(out, a, b, fxn=custom_uop_gemm, grad_fxn=custom_gemm_bw)[0]
if k_sharded: out = out.sum(0)
out = out.squeeze(0) if squeeze else out
if unfold_batch: out = out.reshape(orig_batch, -1, out.shape[-1])
if w_post_scale is not None: out = (out * w_post_scale.reshape(*([1]*(out.ndim-1)), -1)).cast(out.dtype)
return out