Feat (examples/generative): block-based optimization for GPTQ (#1046)

---------

Co-authored-by: i-colbert <[email protected]>

src/brevitas_examples/llm/llm_quant/gpxq.py

@@ -3,39 +3,144 @@
 # SPDX-License-Identifier: BSD-3-Clause
 """
 
+from copy import deepcopy
+
+from accelerate.utils.operations import send_to_device
 import torch
 from tqdm import tqdm
 
+from brevitas.graph.calibrate import disable_return_quant_tensor
+from brevitas.graph.calibrate import DisableEnableQuantization
+from brevitas.graph.calibrate import restore_return_quant_tensor
 from brevitas.graph.gpfq import gpfq_mode
 from brevitas.graph.gptq import gptq_mode
+from brevitas.graph.gpxq import StopFwdException
+from brevitas.utils.python_utils import recurse_getattr
+
+
+@torch.no_grad()
+def block_optimization(model, dataloader, block_name, context_manager_func, context_manager_kwargs):
+    disable_quant_inference = DisableEnableQuantization()
+    cache_state = model.config.use_cache
+    model.config.use_cache = False
+    blocks = recurse_getattr(model, block_name)
+    first_block = blocks[0]
+    cached_args, cached_kwargs = [], []
+
+    # Intercept input to first block
+    def intercept_input(module, args, kwargs):
+        args = send_to_device(args, 'cpu')
+        kwargs = send_to_device(kwargs, 'cpu')
+        cached_args.append(args)
+        cached_kwargs.append(kwargs)
+        raise StopFwdException
+
+    # Intercept output from block N-1 to set it as input to block N
+    def intercept_output(module, args, kwargs, output):
+        if isinstance(output, tuple):
+            output = output[0]
+        output = send_to_device(output, 'cpu')
+        cached_args.append((output,))
+        raise StopFwdException
+
+    # Collect input to first block
+    if not context_manager_kwargs.get('use_quant_activations', True):
+        return_quant_tensor_state = disable_return_quant_tensor(model)
+        disable_quant_inference.disable_act_quantization(model, is_training=model.training)
+        disable_quant_inference.disable_bias_quantization(model, is_training=model.training)
+
+    hook = first_block.register_forward_pre_hook(intercept_input, with_kwargs=True)
+    for inps in dataloader:
+        try:
+            model(**inps)
+        except StopFwdException:
+            pass
+    hook.remove()
+
+    if not context_manager_kwargs.get('use_quant_activations', True):
+        disable_quant_inference.enable_act_quantization(model, is_training=model.training)
+        disable_quant_inference.enable_bias_quantization(model, is_training=model.training)
+        restore_return_quant_tensor(model, return_quant_tensor_state)
+
+    # Iterate through all the blocks
+    for index, block in tqdm(enumerate(blocks), desc="Blocks", total=len(blocks)):
+        with context_manager_func(block, **context_manager_kwargs) as gpxq:
+            for _ in tqdm(range(gpxq.num_layers), desc="Layers", leave=False):
+                for args, kwargs in zip(cached_args, cached_kwargs):
+                    args = send_to_device(args, 'cuda')
+                    kwargs = send_to_device(kwargs, 'cuda')
+                    block(*args, **kwargs)
+                gpxq.update()
+
+        if index < len(blocks) - 1:
+            # Once the block is done, we need to update the input to the next block
+            past_cached_args, past_cached_kwargs = deepcopy(cached_args), deepcopy(cached_kwargs)
+            cached_args = []
+            hook = block.register_forward_hook(intercept_output, with_kwargs=True)
+
+            if not context_manager_kwargs.get('use_quant_activations', True):
+                return_quant_tensor_state = disable_return_quant_tensor(model)
+                disable_quant_inference.disable_act_quantization(model, is_training=model.training)
+                disable_quant_inference.disable_bias_quantization(model, is_training=model.training)
+
+            for args, kwargs in zip(past_cached_args, past_cached_kwargs):
+                try:
+                    args = send_to_device(args, 'cuda')
+                    kwargs = send_to_device(kwargs, 'cuda')
+                    block(*args, **kwargs)
+                except StopFwdException:
+                    pass
+
+            if not context_manager_kwargs.get('use_quant_activations', True):
+                disable_quant_inference.enable_act_quantization(model, is_training=model.training)
+                disable_quant_inference.enable_bias_quantization(model, is_training=model.training)
+                restore_return_quant_tensor(model, return_quant_tensor_state)
+
+            hook.remove()
+    # Restore cache state
+    model.config.use_cache = cache_state
 
 
 @torch.no_grad()
 def apply_gptq(
         model,
         dataloader,
         act_order=True,
+        use_quant_activations=False,
+        create_weight_orig=False,
         group_of_parallel_layers=None,
-        use_quant_activations=True,
-        create_weight_orig=False):
-    with gptq_mode(model,
-                   act_order=act_order,
-                   group_of_parallel_layers=group_of_parallel_layers,
-                   use_quant_activations=use_quant_activations,
-                   create_weight_orig=create_weight_orig) as gptq:
-        gptq_model = gptq.model
-        for _ in tqdm(range(gptq.num_layers)):
-            for inps in dataloader:
-                gptq_model(**inps)
-            gptq.update()
+        block_name=None):
+    if block_name is not None:
+        context_manager_kwargs = {
+            'act_order': act_order,
+            'group_of_parallel_layers': group_of_parallel_layers,
+            'create_weight_orig': create_weight_orig,
+            'use_quant_activations': use_quant_activations}
+        block_optimization(model, dataloader, block_name, gptq_mode, context_manager_kwargs)
+    else:
+        with gptq_mode(model,
+                       use_quant_activations=use_quant_activations,
+                       group_of_parallel_layers=group_of_parallel_layers,
+                       act_order=act_order,
+                       create_weight_orig=create_weight_orig) as gptq:
+            gptq_model = gptq.model
+            for _ in tqdm(range(gptq.num_layers)):
+                for inps in dataloader:
+                    gptq_model(**inps)
+                gptq.update()
 
 
 @torch.no_grad()
-def apply_gpfq(model, dataloader, act_order=True, group_of_parallel_layers=None):
-    with gpfq_mode(model, act_order=act_order,
-                   group_of_parallel_layers=group_of_parallel_layers) as gpfq:
-        gpfq_model = gpfq.model
-        for _ in tqdm(range(gpfq.num_layers)):
-            for inps in dataloader:
-                gpfq_model(**inps)
-            gpfq.update()
+def apply_gpfq(model, dataloader, act_order=True, group_of_parallel_layers=None, block_name=None):
+    if block_name is not None:
+        raise RuntimeError("Block optimization not support for GPFQ at the moment")
+    else:
+        with gpfq_mode(model,
+                       act_order=act_order,
+                       group_of_parallel_layers=group_of_parallel_layers,
+                       create_weight_orig=True) as gpfq:
+            gpfq_model = gpfq.model
+            for _ in tqdm(range(gpfq.num_layers)):
+                for inps in dataloader:
+                    gpfq_model(**inps)
+                gpfq.update()

src/brevitas_examples/llm/main.py

@@ -118,7 +118,6 @@ def validate(args):
 def main(args):
     validate(args)
     set_seed(args.seed)
-
     if args.export_prefix is None:
         args.export_prefix = f"{args.model.replace('/', '--')}"
 
@@ -189,6 +188,8 @@ def main(args):
 
     if require_fx:
         model = get_fx(model)
+        # Blockwise optimization does not work with FX at the moment
+        args.gpxq_block_name = None
 
     # Apply LN affine merging before inserting MHA layers
     # since currently there is support only for merging into Linear
@@ -285,12 +286,17 @@ def main(args):
             calibration_loader,
             act_order=args.gpxq_act_order,
             use_quant_activations=args.gpxq_use_quant_activations,
-            create_weight_orig=args.gpxq_create_weight_orig)
+            create_weight_orig=args.gpxq_create_weight_orig,
+            block_name=args.gpxq_block_name)
         print("GPTQ applied.")
 
     if args.gpfq:
         print("Applying GPFQ...")
-        apply_gpfq(model, calibration_loader, act_order=args.gpxq_act_order)
+        apply_gpfq(
+            model,
+            calibration_loader,
+            act_order=args.gpxq_act_order,
+            block_name=args.gpxq_block_name)
         print("GPFQ applied.")
 
     if args.bias_corr:
@@ -340,6 +346,13 @@ def parse_args(args):
         choices=['wikitext2', 'c4'],
         default='wikitext2',
         help='Dataset to use for quantization (default: %(default)s)')
+    parser.add_argument(
+        '--gpxq-block-name',
+        type=str,
+        default=None,
+        help=
+        'Block name for faster GPxQ optimization. It works only if FX is not needed (default: %(default)s)'
+    )
     parser.add_argument(
         '--weight-bit-width', type=int, default=8, help='Weight bit width. Default: 8.')
     parser.add_argument(