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vLLM/vllm/compilation/reshapes.py
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Russell Bryant e489ad7a21 [Misc] Add SPDX-License-Identifier headers to python source files (#12628)
- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on the SPDX site:
    
    - https://spdx.dev/learn/handling-license-info/
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

commit 5a1cf1cb3b80759131c73f6a9dddebccac039dea
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:36:32 2025 -0500

    Check for SPDX headers using pre-commit
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

---------

Signed-off-by: Russell Bryant <rbryant@redhat.com>
2025-02-02 11:58:18 -08:00

91 lines
3.0 KiB
Python

# SPDX-License-Identifier: Apache-2.0
from typing import Union
import torch.fx
from torch import SymInt
from vllm.logger import init_logger
from .fx_utils import is_func
from .vllm_inductor_pass import VllmInductorPass
logger = init_logger(__name__)
class RedundantReshapesPass(VllmInductorPass):
"""
This is an inductor pass that removes redundant reshape operations.
It is required for RMSNorm-quant fusion to work properly.
That's because apply_fp8_linear adds a reshape, which is redundant
in the 2D-case.
Example graph:
getitem_1: "f16[s0, 4096]" = ...
view_1: "f16[s0, 4096]" = torch.reshape(getitem_1, [-1, 4096])
at = auto_functionalized(static_scaled_fp8_quant, input = view_1, ...)
out: "f8e4m3fn[s0, 4096]" = at[1]
Can be replaced with:
getitem_1: "f16[s0, 4096]" = ...
at = auto_functionalized(static_scaled_fp8_quant, input = getitem_1, ...)
out: "f8e4m3fn[s0, 4096]" = at[1]
"""
def __call__(self, graph: torch.fx.Graph):
self.begin()
self.dump_graph(graph, "before_reshapes")
count = 0
# Remove no-op reshapes/views:
for node in graph.nodes:
if is_func(node, torch.ops.aten.reshape.default):
input, shape = node.args[:2]
input_shape = input.meta["val"].shape
if len(shape) != len(input_shape):
# Reshape changing rank, skip
continue
if shape.count(-1) > 1:
# Invalid reshape args, skip
continue
if all(
self.dims_equivalent(s, i_s)
for s, i_s in zip(shape, input_shape)):
node.replace_all_uses_with(input)
graph.erase_node(node)
count += 1
logger.debug("Removed %s no-op reshapes", count)
self.dump_graph(graph, "after_reshapes")
self.end_and_log()
def dims_equivalent(self, dim: Union[int, torch.fx.Node],
i_dim: Union[int, SymInt]) -> bool:
"""
This function checks if two dimensions are equivalent.
:param dim: The dimension arg to reshape
:param i_dim: The corresponding dimension in the input tensor
:return: Are the dimensions equivalent?
There are three cases in which the dimensions are equivalent:
1. The dimensions are equal (both integers)
2. The reshape dimension is -1 (i.e. inferred)
3. The dimensions both correspond to the same SymInt
While case 2 does not guarantee the dimensions are equal,
they are equal if all other dimensions are equal.
In case 3, the reshape dimension is a torch.fx.Node,
and its value is a SymInt. That value is equal to the
input dimension.
"""
# Case 1 and 2
if dim == i_dim or dim == -1:
return True
# Case 3
return isinstance(dim, torch.fx.Node) and dim.meta["val"] == i_dim