vllm/vllm/_custom_ops.py
Philipp Moritz 379da6dcb5
[Kernel] [FP8] Improve FP8 linear layer performance (#4691)
This PR improves the FP8 performance of linear layers, which had been lacking before (#4118 (comment) and #4118 (comment)).

We noticed that CUBLASLt can find a better algorithm if the first dimension of the matrix is greater than 16. So this PR enlarges matrices appropriately during quantization. This improves FP8 performance and removes the performance regression vs. FP16, in many cases exceeding FP16 performance.

Here are benchmarks on llama3 70b (ITL numbers for 1000 input and 50 output tokens at fixed qps and at TP 4), all FP8 measurements are for dynamic quantization:

qps = 1: 24 ms (FP8, this PR), 32 ms (FP8, previous main), 26 ms (FP16)
qps = 2: 26 ms (FP8, this PR), 34ms (FP8, previous main), 28 ms (FP16) 
qps = 4: 33 ms (FP8, this PR), 44 ms (FP8, previous main), 36 ms (FP16)
qps = 6: 46 ms (FP8, this PR), 56 ms (FP8, previous main), 54 ms (FP16)
qps = 8: 85 ms (FP8, this PR), 85 ms (FP8, previous main), 138 ms (FP16)
2024-05-09 16:38:07 -07:00

278 lines
9.4 KiB
Python

from typing import Dict, Optional, Tuple
import torch
try:
from vllm._C import cache_ops as vllm_cache_ops
from vllm._C import ops as vllm_ops
except ImportError:
pass
# activation ops
def silu_and_mul(out: torch.Tensor, x: torch.Tensor) -> None:
vllm_ops.silu_and_mul(out, x)
def gelu_and_mul(out: torch.Tensor, x: torch.Tensor) -> None:
vllm_ops.gelu_and_mul(out, x)
def gelu_tanh_and_mul(out: torch.Tensor, x: torch.Tensor) -> None:
vllm_ops.gelu_tanh_and_mul(out, x)
def gelu_fast(out: torch.Tensor, x: torch.Tensor) -> None:
vllm_ops.gelu_fast(out, x)
def gelu_new(out: torch.Tensor, x: torch.Tensor) -> None:
vllm_ops.gelu_new(out, x)
# page attention ops
def paged_attention_v1(
out: torch.Tensor,
query: torch.Tensor,
key_cache: torch.Tensor,
value_cache: torch.Tensor,
num_kv_heads: int,
scale: float,
block_tables: torch.Tensor,
seq_lens: torch.Tensor,
block_size: int,
max_seq_len: int,
alibi_slopes: Optional[torch.Tensor],
kv_cache_dtype: str,
kv_scale: float,
) -> None:
vllm_ops.paged_attention_v1(out, query, key_cache, value_cache,
num_kv_heads, scale, block_tables, seq_lens,
block_size, max_seq_len, alibi_slopes,
kv_cache_dtype, kv_scale)
def paged_attention_v2(
out: torch.Tensor,
exp_sum: torch.Tensor,
max_logits: torch.Tensor,
tmp_out: torch.Tensor,
query: torch.Tensor,
key_cache: torch.Tensor,
value_cache: torch.Tensor,
num_kv_heads: int,
scale: float,
block_tables: torch.Tensor,
seq_lens: torch.Tensor,
block_size: int,
max_seq_len: int,
alibi_slopes: Optional[torch.Tensor],
kv_cache_dtype: str,
kv_scale: float,
) -> None:
vllm_ops.paged_attention_v2(out, exp_sum, max_logits, tmp_out, query,
key_cache, value_cache, num_kv_heads, scale,
block_tables, seq_lens, block_size,
max_seq_len, alibi_slopes, kv_cache_dtype,
kv_scale)
# pos encoding ops
def rotary_embedding(
positions: torch.Tensor,
query: torch.Tensor,
key: torch.Tensor,
head_size: int,
cos_sin_cache: torch.Tensor,
is_neox: bool,
) -> None:
vllm_ops.rotary_embedding(positions, query, key, head_size, cos_sin_cache,
is_neox)
def batched_rotary_embedding(positions: torch.Tensor, query: torch.Tensor,
key: torch.Tensor, head_size: int,
cos_sin_cache: torch.Tensor, is_neox: bool,
rot_dim: int,
cos_sin_cache_offsets: torch.Tensor) -> None:
vllm_ops.batched_rotary_embedding(positions, query, key, head_size,
cos_sin_cache, is_neox, rot_dim,
cos_sin_cache_offsets)
# layer norm ops
def rms_norm(out: torch.Tensor, input: torch.Tensor, weight: torch.Tensor,
epsilon: float) -> None:
vllm_ops.rms_norm(out, input, weight, epsilon)
def fused_add_rms_norm(input: torch.Tensor, residual: torch.Tensor,
weight: torch.Tensor, epsilon: float) -> None:
vllm_ops.fused_add_rms_norm(input, residual, weight, epsilon)
# quantization ops
# awq
def awq_dequantize(qweight: torch.Tensor, scales: torch.Tensor,
zeros: torch.Tensor, split_k_iters: int, thx: int,
thy: int) -> torch.Tensor:
return vllm_ops.awq_dequantize(qweight, scales, zeros, split_k_iters, thx,
thy)
def awq_gemm(input: torch.Tensor, qweight: torch.Tensor, qzeros: torch.Tensor,
scales: torch.Tensor, split_k_iters: int) -> torch.Tensor:
return vllm_ops.awq_gemm(input, qweight, qzeros, scales, split_k_iters)
# gptq
def gptq_gemm(a: torch.Tensor, b_q_weight: torch.Tensor,
b_gptq_qzeros: torch.Tensor, b_gptq_scales: torch.Tensor,
b_g_idx: torch.Tensor, use_exllama: bool,
bit: int) -> torch.Tensor:
return vllm_ops.gptq_gemm(a, b_q_weight, b_gptq_qzeros, b_gptq_scales,
b_g_idx, use_exllama, bit)
def gptq_shuffle(q_weight: torch.Tensor, q_perm: torch.Tensor,
bit: int) -> None:
vllm_ops.gptq_shuffle(q_weight, q_perm, bit)
# squeezellm
def squeezellm_gemm(vec: torch.Tensor, mat: torch.Tensor, mul: torch.Tensor,
lookup_table: torch.Tensor) -> None:
vllm_ops.squeezellm_gemm(vec, mat, mul, lookup_table)
# marlin
def marlin_gemm(a: torch.Tensor, b_q_weight: torch.Tensor,
b_scales: torch.Tensor, workspace: torch.Tensor, size_m: int,
size_n: int, size_k: int) -> torch.Tensor:
return vllm_ops.marlin_gemm(a, b_q_weight, b_scales, workspace, size_m,
size_n, size_k)
# aqlm
def aqlm_gemm(input: torch.Tensor, codes: torch.Tensor,
codebooks: torch.Tensor, scales: torch.Tensor,
codebook_partition_sizes: torch.Tensor,
bias: Optional[torch.Tensor]) -> torch.Tensor:
return vllm_ops.aqlm_gemm(input, codes, codebooks, scales,
codebook_partition_sizes, bias)
def aqlm_dequant(codes: torch.Tensor, codebooks: torch.Tensor,
codebook_partition_sizes: torch.Tensor) -> torch.Tensor:
return vllm_ops.aqlm_dequant(codes, codebooks, codebook_partition_sizes)
# gptq_marlin
def gptq_marlin_repack(b_q_weight: torch.Tensor, perm: torch.Tensor,
size_k: int, size_n: int,
num_bits: int) -> torch.Tensor:
return vllm_ops.gptq_marlin_repack(b_q_weight, perm, size_k, size_n,
num_bits)
def gptq_marlin_gemm(a: torch.Tensor, b_q_weight: torch.Tensor,
b_scales: torch.Tensor, g_idx: torch.Tensor,
perm: torch.Tensor, workspace: torch.Tensor,
num_bits: int, size_m: int, size_n: int, size_k: int,
is_k_full: bool) -> torch.Tensor:
return vllm_ops.gptq_marlin_gemm(a, b_q_weight, b_scales, g_idx, perm,
workspace, num_bits, size_m, size_n,
size_k, is_k_full)
# fp8
def scaled_fp8_quant(
input: torch.Tensor,
scale: Optional[torch.Tensor] = None,
batch_dim_padding: Optional[int] = None,
) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Quantize input tensor to FP8 and return quantized tensor and scale.
This function supports both static and dynamic quantization: If you
provide the scale, it will use static scaling and if you omit it,
the scale will be determined dynamically. The function also allows
optional padding of the output tensor for downstream kernels that
will benefit from padding.
Args:
input: The input tensor to be quantized to FP8
scale: Optional scaling factor for the FP8 quantization
batch_dim_padding: If specified, pad the first dimension
of the output to at least this value.
Returns:
Tuple[torch.Tensor, torch.Tensor]: The output tensor in FP8 and
scaling factor.
"""
if batch_dim_padding:
shape = (max(batch_dim_padding, input.shape[0]), *input.shape[1:])
output = torch.empty(shape,
device=input.device,
dtype=torch.float8_e4m3fn)
else:
output = torch.empty_like(input, dtype=torch.float8_e4m3fn)
if scale is None:
scale = torch.zeros(1, device=input.device, dtype=torch.float32)
vllm_ops.dynamic_scaled_fp8_quant(output, input, scale)
else:
vllm_ops.static_scaled_fp8_quant(output, input, scale)
return output, scale
# moe
def moe_align_block_size(topk_ids: torch.Tensor, num_experts: int,
block_size: int, sorted_token_ids: torch.Tensor,
experts_ids: torch.Tensor,
num_tokens_post_pad: torch.Tensor) -> None:
vllm_ops.moe_align_block_size(topk_ids, num_experts, block_size,
sorted_token_ids, experts_ids,
num_tokens_post_pad)
def reshape_and_cache(
key: torch.Tensor,
value: torch.Tensor,
key_cache: torch.Tensor,
value_cache: torch.Tensor,
slot_mapping: torch.Tensor,
kv_cache_dtype: str,
kv_scale: float,
) -> None:
vllm_cache_ops.reshape_and_cache(key, value, key_cache, value_cache,
slot_mapping, kv_cache_dtype, kv_scale)
def reshape_and_cache_flash(
key: torch.Tensor,
value: torch.Tensor,
key_cache: torch.Tensor,
value_cache: torch.Tensor,
slot_mapping: torch.Tensor,
kv_cache_dtype: str,
) -> None:
vllm_cache_ops.reshape_and_cache_flash(key, value, key_cache, value_cache,
slot_mapping, kv_cache_dtype)
def copy_blocks(key_caches: torch.Tensor, value_caches: torch.Tensor,
block_mapping: torch.Tensor) -> None:
vllm_cache_ops.copy_blocks(key_caches, value_caches, block_mapping)
def swap_blocks(src: torch.Tensor, dst: torch.Tensor,
block_mapping: Dict[int, int]) -> None:
vllm_cache_ops.swap_blocks(src, dst, block_mapping)
def convert_fp8(output: torch.Tensor, input: torch.Tensor) -> None:
vllm_cache_ops.convert_fp8(output, input)
#TODO: cuda_utils, custom_ar