linear.py 30.8 KB
Newer Older
1
2
3
4
5
# Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
#
# See LICENSE for license information.

"""Linear API"""
6
import warnings
7
from typing import Union, Optional, Callable, Tuple, List, Dict, Any
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

import torch
from torch.nn.parameter import Parameter

import transformer_engine_extensions as tex

from .base import (
    get_workspace,
    _prepare_backward,
    get_ub,
    TransformerEngineBaseModule,
    _2X_ACC_FPROP,
    _2X_ACC_DGRAD,
    _2X_ACC_WGRAD,
)
from ..fp8 import get_fp8_te_dtype
from ..utils import (
    divide,
    get_default_init_method,
    cast_if_needed,
28
    assert_dim_for_fp8_exec,
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
)
from ..distributed import (
    set_tensor_model_parallel_attributes,
    get_distributed_world_size,
    allreduce,
    initialize_affine_weight_gpu,
    reduce_scatter_along_first_dim,
    gather_along_first_dim,
    gather_along_last_dim,
)
from ..cpp_extensions import (
    fp8_gemm,
    gemm,
    fp8_cast_transpose_fused,
    cast_to_fp8,
)
from ..constants import GemmParallelModes, dist_group_type
46
from ..jit import no_torch_dynamo
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84


__all__ = ["Linear"]


class _Linear(torch.autograd.Function):
    """Linear semi-top level module
    Calls custom cuda extensions.
    """

    @staticmethod
    def forward(
        ctx,
        weight: torch.Tensor,
        weight_fp8: Union[torch.Tensor, None],
        weight_t_fp8: Union[torch.Tensor, None],
        inp: torch.Tensor,
        bias: torch.Tensor,
        use_bias: bool,
        is_first_microbatch: Union[bool, None],
        fp8: bool,
        fp8_calibration: bool,
        fp8_meta: Dict[str, Any],
        fuse_wgrad_accumulation: bool,
        tp_group: Union[dist_group_type, None],
        tp_size: int,
        sequence_parallel: bool,
        tensor_parallel: bool,
        activation_dtype: torch.dtype,
        parallel_mode: Union[str, None],
        is_grad_enabled: bool,
        ub_split_rs: bool,
        ub_split_ag: bool,
    ) -> torch.Tensor:
        # Make sure input dimensions are compatible
        in_features = weight.shape[-1]
        assert inp.shape[-1] == in_features, "GEMM not possible"
        inputmat = inp.view((-1, in_features))
85
        if fp8:
86
87
            assert_dim_for_fp8_exec(inputmat)
            assert_dim_for_fp8_exec(weight)
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213

        update_fp8_weights = is_first_microbatch is None or is_first_microbatch

        if ub_split_rs:
            tp_world_size = get_distributed_world_size(tp_group)
            if tp_world_size == 1:
                ub_split_rs = False
        # Cast for native AMP
        inputmat = cast_if_needed(inputmat, activation_dtype)
        inputmat_no_fp8 = inputmat

        if fp8:
            fp8_dtype_forward = get_fp8_te_dtype(fp8_meta["recipe"], fprop_tensor=True)

            if not fp8_meta["recipe"].override_linear_precision.wgrad:
                if is_grad_enabled:
                    inputmat, inputmat_t = fp8_cast_transpose_fused(
                        inputmat,
                        fp8_meta["scaling_fwd"],
                        tex.FP8FwdTensors.GEMM1_INPUT,
                        fp8_dtype_forward,
                    )
                else:
                    inputmat = cast_to_fp8(
                        inputmat,
                        fp8_meta["scaling_fwd"],
                        tex.FP8FwdTensors.GEMM1_INPUT,
                        fp8_dtype_forward,
                    )
            else:
                inputmat, inputmat_t = cast_to_fp8(
                    inputmat,
                    fp8_meta["scaling_fwd"],
                    tex.FP8FwdTensors.GEMM1_INPUT,
                    fp8_dtype_forward,
                ), None

        # Column Parallel Linear
        if parallel_mode == "column" and sequence_parallel:
            inputmat_total, _ = gather_along_first_dim(inputmat, tp_group)
        else:
            inputmat_total = inputmat

        if fp8:
            bias_dtype = (
                torch.bfloat16
                if activation_dtype == torch.float32
                else activation_dtype
            )
            bias = cast_if_needed(bias, bias_dtype) if use_bias else bias

            if update_fp8_weights:
                if is_grad_enabled:
                    fp8_cast_transpose_fused(
                        weight,
                        fp8_meta["scaling_fwd"],
                        tex.FP8FwdTensors.GEMM1_WEIGHT,
                        fp8_dtype_forward,
                        cast_out=weight_fp8,
                        transpose_out=weight_t_fp8,
                    )
                else:
                    weight_t_fp8 = None
                    weight_fp8 = cast_to_fp8(
                        weight,
                        fp8_meta["scaling_fwd"],
                        tex.FP8FwdTensors.GEMM1_WEIGHT,
                        fp8_dtype_forward,
                    )

            if ub_split_rs:
                ub_obj_projout = get_ub("proj_fprop")
                out = ub_obj_projout.get_ubuf_output(1)
                dim_size = list(inputmat_total.size())
                dim_size[0] = dim_size[0] // tp_world_size
                dim_size[1] = weight.size(0)
                rs_out = torch.empty(dim_size, dtype=activation_dtype, device=inputmat_total.device)
            else:
                dim_size = list(inputmat_total.size())
                dim_size[1] = weight.size(0)
                out = torch.empty(dim_size, dtype=activation_dtype, device=inputmat_total.device)

            _ = fp8_gemm(
                weight_fp8,
                fp8_meta["scaling_fwd"].scale_inv,
                tex.FP8FwdTensors.GEMM1_WEIGHT,
                fp8_dtype_forward,
                inputmat_total,
                fp8_meta["scaling_fwd"].scale_inv,
                tex.FP8FwdTensors.GEMM1_INPUT,
                fp8_dtype_forward,
                activation_dtype,
                get_workspace(),
                bias=bias,
                use_bias=use_bias,
                use_split_accumulator=_2X_ACC_FPROP,
                out=out,
                ub_algo=tex.UbufOverlapAlgo.SPLIT_PIPELINED_RS if ub_split_rs else None,
                ub=ub_obj_projout if ub_split_rs else None,
                extra_output_tensor=rs_out if ub_split_rs else None,
            )
        else:
            # Cast for native AMP
            weight = cast_if_needed(weight, activation_dtype)
            bias = cast_if_needed(bias, activation_dtype) if use_bias else bias

            if fp8_calibration:
                # amax of input
                fp8_meta["scaling_fwd"].amax_history[0][tex.FP8FwdTensors.GEMM1_INPUT] = \
                    torch.amax(inputmat_total).float()
                # amax of weight
                fp8_meta["scaling_fwd"].amax_history[0][tex.FP8FwdTensors.GEMM1_WEIGHT] = \
                    torch.amax(weight).float()

            if ub_split_rs:
                ub_obj_projout = get_ub("proj_fprop")
                out = ub_obj_projout.get_ubuf_output(1)
                dim_size = list(inputmat_total.size())
                dim_size[0] = dim_size[0] // tp_world_size
                dim_size[1] = weight.size(0)
                rs_out = torch.empty(dim_size, dtype=activation_dtype, device=inputmat_total.device)
            else:
                dim_size = list(inputmat_total.size())
                dim_size[1] = weight.size(0)
                out = torch.empty(dim_size, dtype=activation_dtype, device=inputmat_total.device)

214
            _ = gemm(
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
                weight,
                inputmat_total,
                activation_dtype,
                get_workspace(),
                bias=bias,
                use_bias=use_bias,
                out=out,
                ub_algo=tex.UbufOverlapAlgo.SPLIT_PIPELINED_RS if ub_split_rs else None,
                ub=ub_obj_projout if ub_split_rs else None,
                extra_output_tensor=rs_out if ub_split_rs else None,
            )

        if is_grad_enabled:
            fp8_wgrad = fp8 and not fp8_meta["recipe"].override_linear_precision.wgrad
            ctx.save_for_backward(
                inputmat_no_fp8 if weight.requires_grad and not fp8_wgrad else None,
                inputmat_t if weight.requires_grad and fp8_wgrad else None,
                weight,
                weight_t_fp8 if fp8 else None,
                fp8_meta["scaling_fwd"].scale_inv.clone() if fp8 else None,
            )
            ctx.activation_dtype = activation_dtype
            ctx.fp8 = fp8
            ctx.fp8_meta = fp8_meta
            ctx.fuse_wgrad_accumulation = fuse_wgrad_accumulation
            ctx.is_first_microbatch = is_first_microbatch
            ctx.use_bias = use_bias
            ctx.sequence_parallel = sequence_parallel
            ctx.tensor_parallel = tensor_parallel
            ctx.inp_shape = inp.shape
            ctx.parallel_mode = parallel_mode
            ctx.tp_group = tp_group
            ctx.ub_split_ag = ub_split_ag
            ctx.tp_size = tp_size
            ctx.requires_dgrad = inp.requires_grad

        # Row Parallel Linear
        if ub_split_rs:
            out = rs_out
        elif parallel_mode == "row" and sequence_parallel:
            out, _ = reduce_scatter_along_first_dim(out, tp_group)
        elif parallel_mode == "row" and tensor_parallel:
            out, _ = allreduce(out, tp_group)

        # [*, in_features] -> [*, out_features] except first dimension changes for SP
        return out.view(-1, *inp.shape[1:-1], out.shape[-1])


    @staticmethod
    def backward(
        ctx, grad_output: torch.Tensor
    ) -> Tuple[Union[torch.Tensor, None], ...]:
        with _prepare_backward(
            ctx.fp8, ctx.fp8_meta, ctx.tp_group, ctx.tp_size, name="_Linear"
        ):
            (
                inputmat,
                inputmat_t,
                weight,
                weight_t_fp8,
                fwd_scale_inverses,
            ) = ctx.saved_tensors

            if ctx.ub_split_ag:
                tp_world_size = get_distributed_world_size(ctx.tp_group)
                if tp_world_size == 1:
                    ctx.ub_split_ag = False
            if ctx.ub_split_ag:
                dim_size = list(grad_output.size())
                dim_size[0] = dim_size[0] * tp_world_size
                ctx.ub_obj_gradout = get_ub("proj_dgrad")
            (
                grad_output,
                grad_output_c,
                grad_output_t,
                grad_bias,
            ) = TransformerEngineBaseModule.grad_output_preprocess(
                ctx, grad_output, ctx.parallel_mode == "row"
            )

            # Column Parallel Linear
            # Overlap input AG with dgrad
297
            if weight.requires_grad and ctx.parallel_mode == "column" and ctx.sequence_parallel:
298
299
300
301
302
303
304
305
306
307
308
                if ctx.fp8 and not ctx.fp8_meta["recipe"].override_linear_precision.wgrad:
                    inputmat_t_total, handle = gather_along_last_dim(
                        inputmat_t, ctx.tp_group, async_op=ctx.requires_dgrad
                    )
                else:
                    inputmat_total, handle = gather_along_first_dim(
                        inputmat, ctx.tp_group, async_op=ctx.requires_dgrad
                    )
            else:
                inputmat_t_total = inputmat_t
                inputmat_total = inputmat
309
                handle = None
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327

            if ctx.is_first_microbatch is not None:
                accumulate_wgrad_into_param_main_grad = (
                    ctx.fuse_wgrad_accumulation and not ctx.is_first_microbatch
                )
            else:
                accumulate_wgrad_into_param_main_grad = ctx.fuse_wgrad_accumulation

            if ctx.fp8:
                fp8_dtype_forward = get_fp8_te_dtype(
                    ctx.fp8_meta["recipe"], fprop_tensor=True
                )
                fp8_dtype_backward = get_fp8_te_dtype(
                    ctx.fp8_meta["recipe"], fprop_tensor=False
                )

            if ctx.requires_dgrad:
                if ctx.fp8:
328
                    dgrad, _ = fp8_gemm(
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
                        weight_t_fp8,
                        fwd_scale_inverses,
                        tex.FP8FwdTensors.GEMM1_WEIGHT,
                        fp8_dtype_forward,
                        grad_output_c,
                        ctx.fp8_meta["scaling_bwd"].scale_inv,
                        tex.FP8BwdTensors.GRAD_OUTPUT1,
                        fp8_dtype_backward,
                        ctx.activation_dtype,
                        get_workspace(),
                        use_split_accumulator=_2X_ACC_DGRAD,
                        ub_algo=tex.UbufOverlapAlgo.SPLIT_PIPELINED_AG if ctx.ub_split_ag else None,
                        ub=ctx.ub_obj_gradout if ctx.ub_split_ag else None,
                    )
                else:
                    dgrad, _, _ = gemm(
                        weight,
                        grad_output,
                        ctx.activation_dtype,
                        get_workspace(),
                        layout="NN",
                        grad=True,
                        ub_algo=tex.UbufOverlapAlgo.SPLIT_PIPELINED_AG if ctx.ub_split_ag else None,
                        ub=ctx.ub_obj_gradout if ctx.ub_split_ag else None,
                    )

                # Overlap dgrad-RS/AR with wgrad
                if ctx.parallel_mode == "column" and ctx.sequence_parallel:
357
358
                    if handle is not None:
                        handle.wait()
359
360
361
362
363
364
365
366
367
368
369
370
                    dgrad, handle = reduce_scatter_along_first_dim(
                        dgrad, ctx.tp_group, async_op=True
                    )
                elif ctx.parallel_mode == "column" and ctx.tensor_parallel:
                    dgrad, handle = allreduce(dgrad, ctx.tp_group, async_op=True)

            if weight.requires_grad:
                if ctx.fp8:
                    # WGRAD
                    if not ctx.fp8_meta["recipe"].override_linear_precision.wgrad:
                        if ctx.ub_split_ag:
                            grad_output_t = tex.fp8_transpose(grad_output_c, fp8_dtype_backward)
371
                        wgrad, _ = fp8_gemm(
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
                            inputmat_t_total,
                            fwd_scale_inverses,
                            tex.FP8FwdTensors.GEMM1_INPUT,
                            fp8_dtype_forward,
                            grad_output_t,
                            ctx.fp8_meta["scaling_bwd"].scale_inv,
                            tex.FP8BwdTensors.GRAD_OUTPUT1,
                            fp8_dtype_backward,
                            ctx.activation_dtype,
                            get_workspace(),
                            accumulate=accumulate_wgrad_into_param_main_grad,
                            out=weight.main_grad if ctx.fuse_wgrad_accumulation else None,
                            use_split_accumulator=_2X_ACC_WGRAD,
                        )
                    else:
                        wgrad, _, _ = gemm(
                            inputmat_total,
                            grad_output,
                            ctx.activation_dtype,
                            get_workspace(),
                            layout="NT",
                            grad=True,
                            accumulate=accumulate_wgrad_into_param_main_grad,
                            out=weight.main_grad if ctx.fuse_wgrad_accumulation else None,
                        )
                else:
                    # WGRAD
                    wgrad, grad_bias, _ = gemm(
                        inputmat_total,
                        grad_output,
                        ctx.activation_dtype,
                        get_workspace(),
                        layout="NT",
                        grad=True,
                        use_bias=ctx.use_bias,
                        accumulate=accumulate_wgrad_into_param_main_grad,
                        out=weight.main_grad if ctx.fuse_wgrad_accumulation else None,
                    )

            # Column Parallel Linear
            if ctx.parallel_mode == "column" and ctx.tensor_parallel and handle is not None:
                handle.wait()

            if not ctx.use_bias:
                grad_bias = None

418
419
420
        # Handle custom DDP from mcore.
        weight.grad_added_to_main_grad = ctx.fuse_wgrad_accumulation

421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
        return (
            wgrad if weight.requires_grad else None,
            None,
            None,
            dgrad.view(ctx.inp_shape) if ctx.requires_dgrad else None,
            grad_bias,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
        )


class Linear(TransformerEngineBaseModule):
    """
    Applies a linear transformation to the incoming data :math:`y = xA^T + b`

    On NVIDIA GPUs it is a drop-in replacement for `torch.nn.Linear`.

451
452
453
454
455
    .. warning::

        Argument :attr:`skip_weight_param_allocation` is deprecated and will
        be fully removed in future releases.

456
457
458
459
460
461
462
463
464
465
466
    Parameters
    ----------
    in_features : int
                 size of each input sample.
    out_features : int
                  size of each output sample.
    bias : bool, default = `True`
          if set to `False`, the layer will not learn an additive bias.
    init_method : Callable, default = `None`
                 used for initializing weights in the following way: `init_method(weight)`.
                 When set to `None`, defaults to `torch.nn.init.normal_(mean=0.0, std=0.023)`.
cyanguwa's avatar
cyanguwa committed
467
468
469
470
471
472
473
474
    parameters_split : Optional[Union[Tuple[str, ...], Dict[str, int]]], default = None
                      if a tuple of strings or a dict of strings to integers is provided,
                      the weight and bias parameters of the module are exposed as `N` separate
                      `torch.nn.parameter.Parameter`s each, split along the first dimension,
                      where `N` is the length of the argument and the strings contained are the
                      names of the split parameters. In the case of a tuple, each parameter
                      has the same shape. In the case of a dict, the values give the
                      `out_features` for each projection.
475
476
477
478
    device : Union[torch.device, str], default = "cuda"
          The device on which the parameters of the model will allocated. It is the user's
          responsibility to ensure all parameters are moved to the GPU before running the
          forward pass.
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509

    Parallelism parameters
    ----------------------
    sequence_parallel : bool, default = `False`
                       if set to `True`, uses sequence parallelism.
    tp_group : ProcessGroup, default = `None`
              tensor parallel process group.
    tp_size : int, default = 1
             used as TP (tensor parallel) world size when TP groups are not formed during
             initialization. In this case, users must call the
             `set_tensor_parallel_group(tp_group)` method on the initialized module before the
             forward pass to supply the tensor parallel group needed for tensor and sequence
             parallel collectives.
    parallel_mode : {None, 'Column', 'Row'}, default = `None`
                   used to decide whether this Linear layer is Column Parallel Linear or Row
                   Parallel Linear as described `here <https://arxiv.org/pdf/1909.08053.pdf>`_.
                   When set to `None`, no communication is performed.

    Optimization parameters
    -----------------------
    fuse_wgrad_accumulation : bool, default = 'False'
                             if set to `True`, enables fusing of creation and accumulation of
                             the weight gradient. When enabled, it is assumed that the weights
                             have an additional `main_grad` attribute (used instead of the
                             regular `grad`) which is a pre-allocated buffer of the correct
                             size to accumulate gradients in.
    return_bias : bool, default = `False`
                 when set to `True`, this module will not apply the additive bias itself, but
                 instead return the bias value during the forward pass together with the
                 output of the linear transformation :math:`y = xA^T`. This is useful when
                 the bias addition can be fused to subsequent operations.
510
    params_dtype : torch.dtype, default = `torch.get_default_dtype()`
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
                  it controls the type used to allocate the initial parameters. Useful when
                  the model is trained with lower precision and the original FP32 parameters
                  would not fit in GPU memory.
    """

    def __init__(
        self,
        in_features: int,
        out_features: int,
        sequence_parallel: bool = False,
        fuse_wgrad_accumulation: bool = False,
        tp_group: Optional[dist_group_type] = None,
        tp_size: int = 1,
        get_rng_state_tracker: Optional[Callable] = None,
        init_method: Optional[Callable] = None,
        bias: bool = True,
        return_bias: bool = False,
528
        params_dtype: Optional[torch.dtype] = None,
529
530
        parallel_mode: Optional[str] = None,
        skip_weight_param_allocation: bool = False,
cyanguwa's avatar
cyanguwa committed
531
        parameters_split: Optional[Union[Tuple[str, ...], Dict[str, int]]] = None,
532
533
        ub_split_rs: bool = False,
        ub_split_ag: bool = False,
534
        device: Union[torch.device, str] = "cuda",
535
536
    ) -> None:
        super().__init__()
537

538
539
540
541
542
543
544
545
        if skip_weight_param_allocation:
            warnings.warn(
                "Argument `skip_weight_param_allocation` is deprecated and"
                "will be fully removed in future releases. It has ignored"
                "starting from v0.11.",
                category=DeprecationWarning,
            )

546
        params_dtype = torch.get_default_dtype() if params_dtype is None else params_dtype
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
        self.in_features = in_features
        self.out_features = out_features
        self.fuse_wgrad_accumulation = fuse_wgrad_accumulation
        self.use_bias = bias
        self.return_bias = return_bias
        self.apply_bias = bias and not return_bias
        self.parameters_split = parameters_split
        self.ub_split_rs = ub_split_rs
        self.ub_split_ag = ub_split_ag

        if ub_split_rs or ub_split_ag:
            assert (
                tex.userbuf_comm_available()
            ), "Userbuffer communication backend not available."

        if tp_group is None:
            self.tp_size = tp_size
            if tp_size == 1:
                self.set_tensor_parallel_group(tp_group)
        else:
            self.tp_size = get_distributed_world_size(tp_group)
            self.set_tensor_parallel_group(tp_group)
        self.set_nccl_overlap_warning_if_tp()

        self.parallel_mode = parallel_mode
        assert (
            self.parallel_mode in GemmParallelModes
        ), f"parallel_mode {parallel_mode} not supported"

        if self.parallel_mode == "column":
            self.out_features = divide(self.out_features, self.tp_size)
        elif self.parallel_mode == "row":
            self.in_features = divide(self.in_features, self.tp_size)

        if init_method is None:
            init_method = get_default_init_method()

        self.sequence_parallel = (self.tp_size > 1) and sequence_parallel

586
587
        self.weight_tensor = torch.empty(
            self.out_features, self.in_features,
588
            device=device, dtype=params_dtype)
589
590
591
592
593
594
595
596
597
598

        initialize_affine_weight_gpu(
            self.weight_tensor,
            init_method,
            get_rng_state_tracker,
            partition_dim=1 if self.parallel_mode == "row" else 0,
            stride=1,
        )

        if self.use_bias:
599
            self.bias_tensor = torch.empty(self.out_features, device=device, dtype=params_dtype)
600
        else:
601
            self.bias_tensor = torch.Tensor().to(dtype=params_dtype, device=device)
602

603
604
        with torch.no_grad():
            self.bias_tensor.zero_()
605

606
        if parameters_split is None:
cyanguwa's avatar
cyanguwa committed
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
            parameters_split = {"": self.out_features}
        elif isinstance(parameters_split, tuple):
            assert (
                self.out_features % len(parameters_split) == 0
            ), f"Weight and bias params cannot be split into {len(parameters_split)} parts"
            split_size = self.out_features // len(parameters_split)
            parameters_split = {key: split_size for key in parameters_split}
        elif isinstance(parameters_split, dict):
            overall_split_size = sum(parameters_split.values())
            assert(
                self.out_features == overall_split_size
            ), f"Overall sum of parameters_split (={overall_split_size}) does not match "\
               f"to out features (={self.out_features})"
        else:
            assert False, "Type of 'parameters_split' is not None, tuple or dict"
        self.updated_parameters_split = parameters_split
623

624
625
        self.weight_names = []
        self.bias_names = []
626

cyanguwa's avatar
cyanguwa committed
627
628
        slice_begin = 0
        for pname, slice_size in parameters_split.items():
629
630
            wname = pname + "weight"
            bname = pname + "bias"
631

cyanguwa's avatar
cyanguwa committed
632
633
            slice_end = slice_begin + slice_size

634
            self.register_parameter(
cyanguwa's avatar
cyanguwa committed
635
                wname, Parameter(self.weight_tensor[slice_begin:slice_end])
636
            )
637

638
639
640
641
642
643
            set_tensor_model_parallel_attributes(
                tensor=getattr(self, wname),
                is_parallel=True,
                dim=1 if parallel_mode == "row" else 0,
                stride=1,
            )
644

645
            if self.use_bias:
646
                self.register_parameter(
cyanguwa's avatar
cyanguwa committed
647
                    bname, Parameter(self.bias_tensor[slice_begin:slice_end])
648
                )
649
650
                if parallel_mode == "row":
                    setattr(getattr(self, bname), "sequence_parallel", sequence_parallel)
651
            else:
652
                setattr(self, bname, torch.Tensor().to(dtype=params_dtype, device=device))
653

654
655
            if parallel_mode == "column":
                set_tensor_model_parallel_attributes(getattr(self, bname), True, 0, 1)
656

657
658
            self.weight_names.append(wname)
            self.bias_names.append(bname)
659

cyanguwa's avatar
cyanguwa committed
660
661
            slice_begin = slice_end

662
663
664
665
666
667
668
669
670
        self.fp8_weight_shapes.append(torch.Size((self.out_features, self.in_features)))

        # For RPL, bias has to be added after TP collectives
        # So it cannot be fused with the GEMM
        if self.parallel_mode == "row" and self.apply_bias:
            self.gemm_bias_unfused_add = True
        else:
            self.gemm_bias_unfused_add = False

671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
    def get_fp8_weights_scratchpad(
        self,
        is_first_microbatch: Union[bool, None],
    ) -> List[torch.Tensor]:
        """
        Fetch the fp8 weight tensor placeholders if they exist (when
        `is_first_microbatch` is not `None`) or return empty fp8 weight
        tensors (if `is_first_microbatch is None`)
        """
        if not self.fp8:
            return [None, None]

        if is_first_microbatch is None:
            # Return empty weight placeholders for each fwd/bwd pass
            fp8_weight_tensors = self.get_fp8_weights_empty_tensors(
                is_first_microbatch
            )
        else:
            # These persistent weight placeholders should've been created in
            # `set_fp8_weights` method
            fp8_weight_tensors = [self.weight1_fp8, self.weight1_t_fp8]

        return fp8_weight_tensors

695
    @no_torch_dynamo
696
697
698
699
700
701
702
703
704
705
    def forward(
        self,
        inp: torch.Tensor,
        weight: Optional[torch.Tensor] = None,
        bias: Optional[torch.Tensor] = None,
        is_first_microbatch: Optional[bool] = None,
    ) -> Union[torch.Tensor, Tuple[torch.Tensor, ...]]:
        """
        Apply the linear transformation to the input.

706
707
708
709
710
        .. warning::

            Arguments :attr:`weight` and :attr:`bias` are deprecated and will
            be fully removed in future releases.

711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
        Parameters
        ----------
        inp : torch.Tensor
             Input tensor.
        is_first_microbatch : {True, False, None}, default = None
                             During training using either gradient accumulation or
                             pipeline parallelism a minibatch of data is further split
                             into microbatches. Between the microbatches of the same minibatch
                             the model weights are not updated. Setting this parameter indicates
                             whether the current microbatch is the first in a minibatch or not.
                             When set, this parameter enables additional optimizations:

                             * during FP8 training, it allows caching of the FP8 versions of
                               the weights
                             * it also allows skipping gradient accumulation during the
                               first microbatch (since it is the first gradient being
                               produced)
        """

730
731
732
733
734
735
        if weight is not None or bias is not None:
            raise RuntimeError(
                "Arguments `weight` and `bias` are deprecated and "
                "will be fully removed in future releases."
            )

736
737
        with self.prepare_forward(inp, is_first_microbatch) as inp:
            bias_tensor = (
738
                self.bias if self.parameters_split is None
739
                else self.bias_tensor if not torch.is_grad_enabled()
cyanguwa's avatar
cyanguwa committed
740
741
                else self.noop_cat("bias_tensor", self.bias_names,
                    self.updated_parameters_split)
742
743
            )
            weight_tensor = (
744
                self.weight if self.parameters_split is None
745
                else self.weight_tensor if not torch.is_grad_enabled()
cyanguwa's avatar
cyanguwa committed
746
747
                else self.noop_cat("weight_tensor", self.weight_names,
                    self.updated_parameters_split)
748
749
            )

750
751
752
753
754
            # Fetch the fp8 weights placeholders (for linear/gemm)
            weight1_fp8, weight1_t_fp8 = self.get_fp8_weights_scratchpad(
                is_first_microbatch
            )

755
756
757
758
759
760
761
762
            if torch.is_grad_enabled():
                linear_fn = _Linear.apply
                args = []
            else:
                linear_fn = _Linear.forward
                args = [None]
            args += (
                weight_tensor,
763
764
                weight1_fp8,
                weight1_t_fp8,
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
                inp,
                bias_tensor,
                self.apply_bias and not self.gemm_bias_unfused_add,
                is_first_microbatch,
                self.fp8,
                self.fp8_calibration,
                self.fp8_meta,
                self.fuse_wgrad_accumulation,
                self.tp_group,
                self.tp_size,
                self.sequence_parallel,
                self.tp_size > 1,
                self.activation_dtype,
                self.parallel_mode,
                torch.is_grad_enabled(),
                self.ub_split_rs,
                self.ub_split_ag,
            )
            out = linear_fn(*args)

        if self.gemm_bias_unfused_add:
            out = out + cast_if_needed(bias_tensor, self.activation_dtype)

        if self.return_bias:
            return out, cast_if_needed(bias_tensor, self.activation_dtype)
        return out