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Author SHA1 Message Date
Wing Lian
9793faf6dc pre-commit formatting fixes
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2023-08-05 22:46:02 -04:00
ssmi153
64852ae15a Whitespace bug fix
Command had accidentally been moved out of if-else block.
2023-08-05 15:08:44 +12:00
ssmi153
1fed74b1d9 Catch configs without pretraining_tp 2023-08-05 11:45:12 +12:00
ssmi153
a300a4db1d Fix XFormers attention for Llama-2 70B (GQA)
Updated XFormers MonkeyPatch to handle GQA as used in Llama-2 70B. All the updated code is taken directly from the Transformers library: 07360b6c9c (diff-06392bad3b9e97be9ade60d4ac46f73b6809388f4d507c2ba1384ab872711c51) from their llama_modeling.py file.
2023-08-05 11:01:44 +12:00

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@@ -7,6 +7,7 @@ import math
from typing import Optional, Tuple
import torch
import torch.nn.functional as F
import transformers.models.llama.modeling_llama
from torch import nn
@@ -38,21 +39,48 @@ def xformers_forward(
# pylint: disable=duplicate-code
bsz, q_len, _ = hidden_states.size()
query_states = (
self.q_proj(hidden_states)
.view(bsz, q_len, self.num_heads, self.head_dim)
.transpose(1, 2)
)
key_states = (
self.k_proj(hidden_states)
.view(bsz, q_len, self.num_heads, self.head_dim)
.transpose(1, 2)
)
value_states = (
self.v_proj(hidden_states)
.view(bsz, q_len, self.num_heads, self.head_dim)
.transpose(1, 2)
if not hasattr(self, "pretraining_tp"):
self.pretraining_tp = 1
if self.pretraining_tp > 1:
key_value_slicing = (
self.num_key_value_heads * self.head_dim
) // self.pretraining_tp
query_slices = self.q_proj.weight.split(
(self.num_heads * self.head_dim) // self.pretraining_tp, dim=0
)
key_slices = self.k_proj.weight.split(key_value_slicing, dim=0)
value_slices = self.v_proj.weight.split(key_value_slicing, dim=0)
query_states = [
F.linear(hidden_states, query_slices[i]) for i in range(self.pretraining_tp)
]
query_states = torch.cat(query_states, dim=-1)
key_states = [
F.linear(hidden_states, key_slices[i]) for i in range(self.pretraining_tp)
]
key_states = torch.cat(key_states, dim=-1)
value_states = [
F.linear(hidden_states, value_slices[i]) for i in range(self.pretraining_tp)
]
value_states = torch.cat(value_states, dim=-1)
else:
query_states = self.q_proj(hidden_states)
key_states = self.k_proj(hidden_states)
value_states = self.v_proj(hidden_states)
query_states = query_states.view(
bsz, q_len, self.num_heads, self.head_dim
).transpose(1, 2)
key_states = key_states.view(
bsz, q_len, self.num_key_value_heads, self.head_dim
).transpose(1, 2)
value_states = value_states.view(
bsz, q_len, self.num_key_value_heads, self.head_dim
).transpose(1, 2)
kv_seq_len = key_states.shape[-2]
if past_key_value is not None:
@@ -73,6 +101,14 @@ def xformers_forward(
past_key_value = (key_states, value_states) if use_cache else None
# repeat k/v heads if n_kv_heads < n_heads
key_states = transformers.models.llama.modeling_llama.repeat_kv(
key_states, self.num_key_value_groups
)
value_states = transformers.models.llama.modeling_llama.repeat_kv(
value_states, self.num_key_value_groups
)
# We only apply xformers optimizations if we don't need to output the whole attention matrix
if not output_attentions:
query_states = query_states.transpose(1, 2)
@@ -128,10 +164,23 @@ def xformers_forward(
f" {attn_output.size()}"
)
attn_output = attn_output.transpose(1, 2)
attn_output = attn_output.transpose(1, 2).contiguous()
# end x-formers vs. not x-formers if-else block
attn_output = attn_output.reshape(bsz, q_len, self.hidden_size)
if self.pretraining_tp > 1:
attn_output = attn_output.split(self.hidden_size // self.pretraining_tp, dim=2)
o_proj_slices = self.o_proj.weight.split(
self.hidden_size // self.pretraining_tp, dim=1
)
attn_output = sum(
F.linear(attn_output[i], o_proj_slices[i])
for i in range(self.pretraining_tp)
)
else:
attn_output = self.o_proj(attn_output)
return attn_output, attn_weights, past_key_value