Trade subgraph recompute for memory (#12852)
**Description**: Subgraph-level recompute
This PR adds an optional capability trading additional re-computation
for better memory efficiency. Specifically, a pre-defined operator list
used to iterate the Graph to find some subgraphs for recompute, to
reduce some stashed activations whose lifetime across forward and
backward pass.
When training with ORTModule, by default, the graph transformer will
scan the execution graph to find all eligible subgraph to recompute,
along with sizes that can save. An example looks like below.
If we want to enable some of them to recompute, we can define env
variable this way:
`export
ORTMODULE_ENABLE_MEMORY_ALLEVIATION="Mul+FusedMatMul+Cast+Unsqueeze+Unsqueeze+Cast+Sub+Mul+Add+BiasSoftmaxDropout+Cast+:1:-1,BiasGelu+:1:-1,BitmaskDropout+Cast+:1:-1,FusedMatMul+:1:-1,Cast+:1:-1,Mul+Add+:1:-1,Mul+Sub+:1:-1"`
```
[1,0]<stderr>:2,022-10-12 14:47:39.302,954,530 [W:onnxruntime:, memory_alleviation.cc:595 PrintSummary]
[1,0]<stderr>:MemoryAlleviation Summary:
[1,0]<stderr>: User config:
[1,0]<stderr>: Mul+FusedMatMul+Cast+Unsqueeze+Unsqueeze+Cast+Sub+Mul+Add+BiasSoftmaxDropout+Cast+:1,BiasGelu+:1,BitmaskDropout+Cast+:1,FusedMatMul+:1,Cast+:1,Mul+Add+:1,Mul+Sub+:1
[1,0]<stderr>: =================================
[1,0]<stderr>: Subgraph: BitmaskDropout+
[1,0]<stderr>: AlleviationType: Disabled
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x 1,024 x Frequency:1
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: BiasGelu+
[1,0]<stderr>: AlleviationType: Recompute
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x input_ids_dim1 x 4,096 x Frequency:24
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: Reshape[1,0]<stderr>:+
[1,0]<stderr>: AlleviationType: Disabled
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:labels_dim0 x Frequency:1
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: Unsqueeze+Unsqueeze+Cast+Sub+Mul+Mul+FusedMatMul+Cast+Add+BiasSoftmaxDropout+Cast+
[1,0]<stderr>: AlleviationType: Disabled
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x 16 x input_ids_dim1 x input_ids_dim1 x Frequency:23
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: Mul+FusedMatMul+Cast+Unsqueeze+Unsqueeze+Cast+Sub+Mul+Add+BiasSoftmaxDropout+Cast+
[1,0]<stderr>: AlleviationType: Recompute
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x 16 x input_ids_dim1 x input_ids_dim1 x Frequency:1
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: Mul+Add+
[1,0]<stderr>: AlleviationType: Recompute
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x 16 x input_ids_dim1 x 1 x Frequency:24
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: FusedMatMul+Cast+Add+Reshape+Cast+
[1,0]<stderr>: AlleviationType: Disabled
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x 16 x input_ids_dim1 x 2 x 4 x Frequency:24
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: Mul+Sub+
[1,0]<stderr>: AlleviationType: Recompute
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x 16 x input_ids_dim1 x 1 x Frequency:24
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: Cast+
[1,0]<stderr>: AlleviationType: Recompute
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:1,024 x 1,024 x Frequency:97
[1,0]<stderr>: PatternShape:3 x 1,024 x Frequency:1
[1,0]<stderr>: PatternShape:8 x 64 x Frequency:24
[1,0]<stderr>: PatternShape:1,024 x 4,096 x Frequency:24
[1,0]<stderr>: PatternShape:4,096 x Frequency:24
[1,0]<stderr>: PatternShape:4,096 x 1,024 x Frequency:24
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: Subgraph: FusedMatMul+
[1,0]<stderr>: AlleviationType: Recompute
[1,0]<stderr>: Patterns:
[1,0]<stderr>: PatternShape:input_ids_dim0 x input_ids_dim1 x 4,096 x Frequency:24
[1,0]<stderr>: --------------------------------
[1,0]<stderr>: =================================
```
"Type config:" whether recompute is enabled by users. 0 - disable, 1-
enable.
"Subgraph" means what kind of subgraph will be recomputed, in this case,
it is a single node "Gelu", and it will be "Recompute".
"Shape && Frequency" means, for this recompute, one tensor of size
(batch size, 500) will be saved because it will be recomputed.
**Baseline**
On a 1P model (DEBERTA V2), sequence length 256, training with 16 A100
GPUs. With latest main branch, we can run batch size 16, and the maximum
batch size < 32. So 16 is usually chosen by data scientists. 65% of 40GB
memory is used during training. The SamplesPerSec=479.2543353561354.
**With this PR**
Gelu is recomputed for saving memory peak, batch size 32 can be run. The
97% of 40GB A100 is used, the SamplesPerSec=562.041593991271 (**1.17X**
of baseline).
**Motivation and Context**
- Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here.
