The IPUConfig
class enables defining configuration for PopArt and for PyTorch for the IPU, allowing to control the behavior of the IPUs. It is JSON-serializable, and can be loaded from and saved to a local directory or file, as well as from and to the 🤗 Hub.
Each example script in /examples
and Jupyter notebook in /notebooks
uses IPUConfig
.
layers_per_ipu
and inference_layers_per_ipu
for encoder/decoder models
The configuration parameter layers_per_ipu
specifies the number of layers that will be put on each IPU for pipelined execution during training. There is an equivalent parameter for inference, inference_layers_per_ipu
.
Ordinarily, you can specify the number of layers that you want on each IPU, but the situation is slightly different for the encoder/decoder models that are used in, for example, text generation.
In these cases, the number of encoder and decoder layers must be split evenly across all IPUs and so you can use the wildcard value (-1) for layers_per_ipu
and inference_layers_per_ipu
.
For example, in the Summarization on IPUs - Fine-tuning notebook, we have the IPU configuration for inference defined as:
ipu_config_name = 'Graphcore/t5-small-ipu'
ipu_config = IPUConfig.from_pretrained(
ipu_config_name,
executable_cache_dir=executable_cache_dir,
# -1 wildcard,
# split encoder and decoder layers evenly across IPUs
# for inference
inference_layers_per_ipu=[-1]
)
( replication_factor: int = 1 inference_replication_factor: int = 1 gradient_accumulation_steps: int = 1 layers_per_ipu: typing.List[int] = [-1] inference_layers_per_ipu: typing.Optional[typing.List[int]] = None ipus_per_replica: typing.Optional[int] = None inference_ipus_per_replica: typing.Optional[int] = None optimizer_state_offchip: bool = False replicated_tensor_sharding: bool = False matmul_proportion: typing.Union[float, typing.List[float]] = 0.2 inference_matmul_proportion: typing.Union[float, typing.List[float], NoneType] = None enable_half_partials: bool = True embedding_serialization_factor: typing.Optional[int] = None inference_embedding_serialization_factor: typing.Optional[int] = None serialized_embedding_splits_per_ipu: typing.Optional[typing.List[int]] = None inference_serialized_embedding_splits_per_ipu: typing.Optional[typing.List[int]] = None projection_serialization_factor: typing.Optional[int] = None inference_projection_serialization_factor: typing.Optional[int] = None serialized_projection_splits_per_ipu: typing.Optional[typing.List[int]] = None inference_serialized_projection_splits_per_ipu: typing.Optional[typing.List[int]] = None recompute_checkpoint_every_layer: bool = False device_iterations: int = 1 inference_device_iterations: int = 1 output_mode: str = 'final' seed: typing.Optional[int] = None auto_loss_scaling: bool = False executable_cache_dir: str = '' **kwargs )
Parameters
int
, optional) —
Sets the seed for the random number generator on the IPU.
bool
, optional, defaults to False
) —
If True
, enables automatic loss scaling on the IPU.
When using float16/half-precision values for activations, gradients, and weights, the loss value needs to be scaled by
a constant factor to avoid underflows or overflows. This adjustment is known as loss scaling. This setting
automatically sets a global loss scaling factor during training.
Note: This is an experimental feature and may not behave as expected.
str
, optional, defaults to ""
) —
Enables caching the compile executables to a directory.
Parameters for controlling the batch size
int
, optional, defaults to 1) —
The number of replicas for data-parallelism during training. It depends on the size of the pipeline as well
as the number of IPUs available. For example: on a Pod16, with a 4-IPU pipeline, the replication_factor must
be between 1 and 4.
int
, optional, defaults to 1) —
The number of replicas for data-parallelism during inference. It depends on the size of the pipeline as well
as the number of IPUs available. For example: on a Pod16, with a 4-IPU pipeline, the replication_factor must
be between 1 and 4.
int
, optional, defaults to 1) —
Number of micro-batches to accumulate for the gradient calculation.
Accumulates the gradient gradient_accumulation
times before updating the model using the gradient.
Parameters related to parallelism
List[int]
) —
Specifies the number of layers that will be put on each IPU for pipelined execution during training.
For instance: [2, 3, 4, 2]
specifies a 4-IPU pipeline, where the first two layers will be put on IPU0,
the following three on IPU1, the next four on IPU2 and the last two on IPU3.
If the default of [-1] is used, the layers will be split evenly over ipus_per_replica
IPUs.
The wildcard value ‘-1’ can also be used in combination with integers.
For instance: [1, 2, -1, -1]
specifies a 4-IPU pipeline, where the first layer is put on IPU0,
the next two layers on IPU1, and the remaining layers split evenly between IPU2 and IPU3.
List[int]
) —
Same as layers_per_ipu
for inference only.
int
, optional, defaults to len(layers_per_ipu)
) —
Specifies the number of IPUs to use during training. This must be consistent with
the number of IPUs used in layers_per_ipu
.
int
, optional, defaults to len(inference_layers_per_ipu) if ipus_per_replica==len(layers_per_ipu) else ipus_per_replica) -- Same as
ipus_per_replica` but for inference only.
Parameters for memory management
bool
, optional, defaults to True
) —
If True
, uses the off-chip memory to store the optimizer state. If False
, uses the on-chip memory.
bool
, optional, defaults to False
) —
Shards the optimizer between replicas with zero-redundancy.
List[float]
or float
, optional, defaults to 0.2) —
Sets the amount of temporary memory made available during training on per-IPU basis.
Use this setting to control the amount of temporary memory available to operations such as:List[float]
or float
) —
Same as matmul_proportion
for inference only.
bool
, optional, defaults to True
) —
If True
, sets the data type of partial results for matrix multiplication and convolution operators to float16.
int
, optional, defaults to 1 if serialized_embedding_splits_per_ipu
is None
) —
The factor to use to serialize embeddings. Nothing happens if embedding_serialization_factor = 1
. For
embedding_serialization_factor > 1
, the torch.nn.Embedding
layer is replaced with a
optimum.graphcore.modeling_utils.SerializedEmbedding
layer.
Note: only one of embedding_serialization_factor
or serialized_embedding_splits_per_ipu
should be provided.
int
, optional, defaults to 1 if inference_serialized_embedding_splits_per_ipu
is None
) —
Same as embedding_serialization_factor
but for inference only.
List[int]
, optional, defaults to None) —
Specifies the number of splits of the embedding layer that will be put on each IPU for pipelined execution.
The format has to be the same as that for layers_per_ipu
however wildcards are not supported.
For instance: [3, 1, 0, 0]
specifies how to place an embedding layer serialized into
4 sub-embedding layers across a 4-IPU pipeline. IPU-1 has 3 splits and IPU-2 has 1 split.
The remaining IPUs have no sub-embedding layers. If an argument to this parameter is provided,
it must:List[int>=0]
with atleast 1 split.ipus_per_replica
[3, 0, 2, 0]
is invalid[3, 1, 0, 0]
for an encoder-decoder model can be split into
[3, 1]
and [0, 0]
, however [0, 1, 2, 0]
split into [0, 1]
and [2, 0]
is invalid.
Note: only one of embedding_serialization_factor
or serialized_embedding_splits_per_ipu
should be set.List[int]
, optional, defaults to None) —
Same as serialized_embedding_splits_per_ipu
but for inference only.
int
, optional, defaults to 1 if serialized_projection_splits_per_ipu
is None
) —
The factor to use to either serialize the matmuls that are performed in the linear projection layer, or,
serialize the projection layer into a set of individual linear layers that can be optionally placed on different IPUs.
Nothing happens if projection_serialization_factor = 1
. If projection_serialization_factor > 1
,
the torch.nn.Linear
layer is replaced by a optimum.graphcore.modeling_utils.SplitProjection
layer
if serialized_projection_splits_per_ipu
is provided and the linear layer’s weights are not tied to another layer.
Otherwise it is replaced by a optimum.graphcore.modeling_utils.SerializedLinear
layer.
Note: only one of projection_serialization_factor
or serialized_projection_splits_per_ipu
should be set.
int
, optional, defaults to 1 if inference_serialized_projection_splits_per_ipu
is None
) —
Same as projection_serialization_factor
but for inference only.
List[int]
, optional, defaults to None) —
Analogous to serialized_embedding_splits_per_ipu
.
Note: only one of projection_serialization_factor
or serialized_projection_splits_per_ipu
should be set.
List[int]
, optional, defaults to None) —
Same as serialized_projection_splits_per_ipu
but for inference only.
bool
, optional, defaults to False
) —
If True
, uses gradient checkpointing at the end of every layer. It can help to reduce the memory impact.
Parameters related to host/device synchronization
int
, optional, defaults to 1) —
Number of iterations the device should run over the data before returning to the user during training. This
is equivalent to running the IPU in a loop over the specified number of iterations, with a new batch of
data each time. However, increasing the number of device iterations is more efficient because the loop runs on the IPU
directly.
int
, optional, defaults to 1) —
Same as device_iterations
for inference.
str
, optional, defaults to "final"
) —
Specifies which data to return from a model.
Allowed values:all
: returns a result for each batch.sum
: returns the sum of all batches.final
: returns the last batch.default
: all
for inference, final
for training.Class for configuring PopArt and PyTorch for the IPU. Handles the conversion to poptorch
options as well as configuration of the
IPU-Pod type specialization.
(
for_inference: bool = False
)
→
int
Computes the factor to apply to the micro batch size to calculate the combined batch size.
(
for_inference: bool = False
compile_only: bool = False
)
→
poptorch.Options
Parameters
bool
, defaults to False
) —
If True
, the resulting poptorch.Options
will be adapted for inference. If False
, the resulting poptorch.Options
will be adapted for training.
bool
, defaults to False
) —
If True, compilation will be performed offline, no IPUs required.
Returns
poptorch.Options
The options representing the IPUConfig
instance.
Creates a poptorch.Options
instance from the IPUConfig
instance.
( update_str: str )
Updates attributes of the IPUConfig
class with attributes from update_str
.
The expected format is ints, floats and strings as is, and for booleans use true
or false
, and for lists
use [a b c d]
. For example: "n_embd=10,resid_pdrop=0.2,scale_attn_weights=false,summary_type=cls_index, matmul_proportion=[0.08 0.2 0.25 0.25]"
.
The keys to change must already exist in the config object.