# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project

import argparse
import copy
import itertools
import pickle as pkl
import time
from collections.abc import Iterable
from typing import Callable, Optional

import torch
import torch.utils.benchmark as TBenchmark
from torch.utils.benchmark import Measurement as TMeasurement
from utils import make_rand_tensors
from weight_shapes import WEIGHT_SHAPES

from vllm import _custom_ops as ops
from vllm.model_executor.layers.quantization.utils.fp8_utils import (
    w8a8_block_fp8_matmul,
)
from vllm.utils import FlexibleArgumentParser, cdiv

DEFAULT_MODELS = list(WEIGHT_SHAPES.keys())
DEFAULT_BATCH_SIZES = [1, 16, 32, 64, 128, 256, 512]
DEFAULT_TP_SIZES = [1]


# bench
def bench_fn(
    label: str, sub_label: str, description: str, fn: Callable, *args, **kwargs
) -> TMeasurement:
    min_run_time = 1

    globals = {
        "args": args,
        "kwargs": kwargs,
        "fn": fn,
    }
    return TBenchmark.Timer(
        stmt="fn(*args, **kwargs)",
        globals=globals,
        label=label,
        sub_label=sub_label,
        description=description,
    ).blocked_autorange(min_run_time=min_run_time)


def bench_int8(
    dtype: torch.dtype,
    m: int,
    k: int,
    n: int,
    label: str,
    sub_label: str,
    bench_kernels: Optional[list[str]] = None,
) -> Iterable[TMeasurement]:
    """Benchmark INT8-based kernels."""
    assert dtype == torch.int8
    a, b = make_rand_tensors(torch.int8, m, n, k)
    scale_a = torch.tensor(1.0, device="cuda", dtype=torch.float32)
    scale_b = torch.tensor(1.0, device="cuda", dtype=torch.float32)
    bias = torch.zeros((n,), device="cuda", dtype=torch.bfloat16)
    azp = torch.zeros((m,), device="cuda", dtype=torch.int32)
    azp_adj = torch.zeros((n,), device="cuda", dtype=torch.int32)

    bench_fns = {
        "pytorch_bf16_bf16_bf16_matmul-no-scales": lambda: torch.mm(
            a.to(dtype=torch.bfloat16), b.to(dtype=torch.bfloat16)
        ),
        "pytorch_fp16_fp16_fp16_matmul-no-scales": lambda: torch.mm(
            a.to(dtype=torch.float16), b.to(dtype=torch.float16)
        ),
        "cutlass_i8_i8_bf16_scaled_mm": lambda: ops.cutlass_scaled_mm(
            a, b, scale_a, scale_b, torch.bfloat16
        ),
        "cutlass_i8_i8_bf16_scaled_mm_bias": lambda: ops.cutlass_scaled_mm(
            a, b, scale_a, scale_b, torch.bfloat16, bias
        ),
        "cutlass_i8_i8_bf16_scaled_mm_azp": lambda: ops.cutlass_scaled_mm_azp(
            a, b, scale_a, scale_b, torch.bfloat16, azp_adj
        ),
        "cutlass_i8_i8_bf16_scaled_mm_azp_bias": lambda: ops.cutlass_scaled_mm_azp(
            a, b, scale_a, scale_b, torch.bfloat16, azp_adj, None, bias
        ),
        "cutlass_i8_i8_bf16_scaled_mm_azp_pt": lambda: ops.cutlass_scaled_mm_azp(
            a, b, scale_a, scale_b, torch.bfloat16, azp_adj, azp
        ),
        "cutlass_i8_i8_bf16_scaled_mm_azp_pt_bias": lambda: ops.cutlass_scaled_mm_azp(
            a, b, scale_a, scale_b, torch.bfloat16, azp_adj, azp, bias
        ),
    }

    timers = []
    for name, fn in bench_fns.items():
        # If bench_kernels is None, run all. Otherwise, run only exact matches.
        if bench_kernels is None or name in bench_kernels:
            print(f"Running {name}")
            timers.append(bench_fn(label, sub_label, name, fn))

    return timers


def bench_fp8(
    dtype: torch.dtype,
    m: int,
    k: int,
    n: int,
    label: str,
    sub_label: str,
    bench_kernels: Optional[list[str]] = None,
) -> Iterable[TMeasurement]:
    """Benchmark FP8-based kernels."""
    assert dtype == torch.float8_e4m3fn
    a, b = make_rand_tensors(torch.float8_e4m3fn, m, n, k)
    a_cont = a.contiguous()
    scale_a = torch.tensor(1.0, device="cuda", dtype=torch.float32)
    scale_b = torch.tensor(1.0, device="cuda", dtype=torch.float32)

    block_scale_a = torch.rand((m, cdiv(k, 128)), device="cuda", dtype=torch.float32)
    block_scale_b = torch.rand(
        cdiv(k, 128), cdiv(n, 128), device="cuda", dtype=torch.float32
    )
    block_scale_a_M_major = block_scale_a.t().contiguous().t()
    block_scale_b_K_major = block_scale_b.t().contiguous().t()
    bias = torch.zeros((n,), device="cuda", dtype=torch.bfloat16)

    print(m, k, n)

    bench_fns = {
        "pytorch_bf16_bf16_bf16_matmul-no-scales": lambda: torch.mm(
            a.to(dtype=torch.bfloat16), b.to(dtype=torch.bfloat16)
        ),
        "pytorch_fp16_fp16_fp16_matmul-no-scales": lambda: torch.mm(
            a.to(dtype=torch.float16), b.to(dtype=torch.float16)
        ),
        "pytorch_fp8_fp8_fp16_scaled_mm": lambda: torch._scaled_mm(
            a, b, scale_a, scale_b, out_dtype=torch.float16
        ),
        "pytorch_fp8_fp8_fp16_scaled_mm_fast_accum": lambda: torch._scaled_mm(
            a, b, scale_a, scale_b, out_dtype=torch.float16, use_fast_accum=True
        ),
        "pytorch_fp8_fp8_bf16_scaled_mm": lambda: torch._scaled_mm(
            a, b, scale_a, scale_b, out_dtype=torch.bfloat16
        ),
        "pytorch_fp8_fp8_bf16_scaled_mm_fast_accum": lambda: torch._scaled_mm(
            a, b, scale_a, scale_b, out_dtype=torch.bfloat16, use_fast_accum=True
        ),
        "cutlass_fp8_fp8_bf16_scaled_mm": lambda: ops.cutlass_scaled_mm(
            a, b, scale_a, scale_b, torch.bfloat16
        ),
        "cutlass_fp8_fp8_fp16_scaled_mm": lambda: ops.cutlass_scaled_mm(
            a, b, scale_a, scale_b, torch.float16
        ),
        "cutlass_fp8_fp8_bf16_scaled_mm_bias": lambda: ops.cutlass_scaled_mm(
            a, b, scale_a, scale_b, torch.bfloat16, bias
        ),
        "cutlass_fp8_fp8_fp16_scaled_mm_bias": lambda: ops.cutlass_scaled_mm(
            a, b, scale_a, scale_b, torch.float16, bias.to(dtype=torch.float16)
        ),
        "triton_fp8_fp8_fp16_scaled_mm_blockwise": lambda: w8a8_block_fp8_matmul(
            a_cont, b.t(), block_scale_a, block_scale_b.t(), (128, 128)
        ),
        "cutlass_fp8_fp8_fp16_scaled_mm_blockwise": lambda: ops.cutlass_scaled_mm(
            a, b, block_scale_a_M_major, block_scale_b_K_major, torch.float16
        ),
    }

    timers = []
    for name, fn in bench_fns.items():
        # If bench_kernels is None, run all. Otherwise, run only exact matches.
        if bench_kernels is None or name in bench_kernels:
            print(f"Running {name}")
            timers.append(bench_fn(label, sub_label, name, fn))

    return timers


def bench(
    dtype: torch.dtype,
    m: int,
    k: int,
    n: int,
    label: str,
    sub_label: str,
    bench_kernels: Optional[list[str]] = None,
) -> Iterable[TMeasurement]:
    if dtype == torch.int8:
        return bench_int8(dtype, m, k, n, label, sub_label, bench_kernels)
    if dtype == torch.float8_e4m3fn:
        return bench_fp8(dtype, m, k, n, label, sub_label, bench_kernels)
    raise ValueError("unsupported type")


# runner
def print_timers(timers: Iterable[TMeasurement]):
    compare = TBenchmark.Compare(timers)
    compare.print()


def run(
    dtype: torch.dtype,
    MKNs: Iterable[tuple[int, int, int]],
    bench_kernels: Optional[list[str]] = None,
) -> Iterable[TMeasurement]:
    results = []
    for m, k, n in MKNs:
        timers = bench(
            dtype,
            m,
            k,
            n,
            f"scaled-{dtype}-gemm",
            f"MKN=({m}x{k}x{n})",
            bench_kernels=bench_kernels,
        )
        print_timers(timers)
        results.extend(timers)
    return results


def make_output(
    data: Iterable[TMeasurement],
    MKNs: Iterable[tuple[int, int, int]],
    base_description: str,
    timestamp=None,
):
    print(f"== All Results {base_description} ====")
    print_timers(data)

    # pickle all the results
    timestamp = int(time.time()) if timestamp is None else timestamp
    with open(f"{base_description}-{timestamp}.pkl", "wb") as f:
        pkl.dump(data, f)


def run_square_bench(args):
    dim_sizes = list(range(args.dim_start, args.dim_end + 1, args.dim_increment))
    MKNs = list(zip(dim_sizes, dim_sizes, dim_sizes))
    data = run(args.dtype, MKNs, bench_kernels=args.kernels)
    make_output(data, MKNs, f"square_bench-{args.dtype}")


def run_range_bench(args):
    dim_sizes = list(range(args.dim_start, args.dim_end, args.dim_increment))
    n = len(dim_sizes)
    Ms = [args.m_constant] * n if args.m_constant is not None else dim_sizes
    Ks = [args.k_constant] * n if args.k_constant is not None else dim_sizes
    Ns = [args.n_constant] * n if args.n_constant is not None else dim_sizes
    MKNs = list(zip(Ms, Ks, Ns))
    data = run(args.dtype, MKNs, bench_kernels=args.kernels)
    make_output(data, MKNs, f"range_bench-{args.dtype}")


def run_model_bench(args):
    print("Benchmarking models:")
    for i, model in enumerate(args.models):
        print(f"[{i}]  {model}")

    def model_shapes(model_name: str, tp_size: int) -> list[tuple[int, int]]:
        KNs = []
        for KN, tp_split_dim in copy.deepcopy(WEIGHT_SHAPES[model_name]):
            KN[tp_split_dim] = KN[tp_split_dim] // tp_size
            KNs.append(KN)
        return KNs

    model_bench_data = []
    models_tps = list(itertools.product(args.models, args.tp_sizes))
    for model, tp_size in models_tps:
        Ms = args.batch_sizes
        KNs = model_shapes(model, tp_size)
        MKNs = []
        for m in Ms:
            for k, n in KNs:
                MKNs.append((m, k, n))

        data = run(args.dtype, MKNs, bench_kernels=args.kernels)
        model_bench_data.append(data)

    # Print all results
    for data, model_tp in zip(model_bench_data, models_tps):
        model, tp_size = model_tp
        print(f"== Results {args.dtype} {model}-TP{tp_size} ====")
        print_timers(data)

    timestamp = int(time.time())

    all_data = []
    for d in model_bench_data:
        all_data.extend(d)
    # pickle all data
    with open(f"model_bench-{args.dtype}-{timestamp}.pkl", "wb") as f:
        pkl.dump(all_data, f)


if __name__ == "__main__":

    def to_torch_dtype(dt):
        if dt == "int8":
            return torch.int8
        if dt == "fp8":
            return torch.float8_e4m3fn
        raise ValueError("unsupported dtype")

    parser = FlexibleArgumentParser(
        description="""
Benchmark Cutlass GEMM.

    To run square GEMMs:
        python3 ./benchmarks/cutlass_benchmarks/w8a8_benchmarks.py --dtype fp8 square_bench --dim-start 128 --dim-end 512 --dim-increment 64
    
    To run constant N and K and sweep M:
        python3 ./benchmarks/cutlass_benchmarks/w8a8_benchmarks.py --dtype fp8 range_bench --dim-start 128 --dim-end 512 --dim-increment 64 --n-constant 16384 --k-constant 16384
    
    To run dimensions from a model:
        python3 ./benchmarks/cutlass_benchmarks/w8a8_benchmarks.py --dtype fp8 model_bench --models meta-llama/Llama-2-7b-hf --batch-sizes 16 --tp-sizes 1
    
    Output:
        - a .pkl file, that is a list of raw torch.benchmark.utils.Measurements for the pytorch and cutlass implementations for the various GEMMs.
            """,  # noqa: E501
        formatter_class=argparse.RawTextHelpFormatter,
    )

    parser.add_argument(
        "--dtype",
        type=to_torch_dtype,
        required=True,
        help="Available options are ['int8', 'fp8']",
    )
    parser.add_argument(
        "--kernels",
        nargs="+",
        type=str,
        default=None,
        help="Exact names of the kernels to benchmark. If not set, runs all kernels.",
    )

    subparsers = parser.add_subparsers(dest="cmd")

    square_parser = subparsers.add_parser("square_bench")
    square_parser.add_argument("--dim-start", type=int, required=True)
    square_parser.add_argument("--dim-end", type=int, required=True)
    square_parser.add_argument("--dim-increment", type=int, required=True)
    square_parser.set_defaults(func=run_square_bench)

    range_parser = subparsers.add_parser("range_bench")
    range_parser.add_argument("--dim-start", type=int, required=True)
    range_parser.add_argument("--dim-end", type=int, required=True)
    range_parser.add_argument("--dim-increment", type=int, required=True)
    range_parser.add_argument("--m-constant", type=int, default=None)
    range_parser.add_argument("--n-constant", type=int, default=None)
    range_parser.add_argument("--k-constant", type=int, default=None)
    range_parser.set_defaults(func=run_range_bench)

    model_parser = subparsers.add_parser("model_bench")
    model_parser.add_argument(
        "--models",
        nargs="+",
        type=str,
        default=DEFAULT_MODELS,
        choices=WEIGHT_SHAPES.keys(),
    )
    model_parser.add_argument(
        "--tp-sizes", nargs="+", type=int, default=DEFAULT_TP_SIZES
    )
    model_parser.add_argument(
        "--batch-sizes", nargs="+", type=int, default=DEFAULT_BATCH_SIZES
    )
    model_parser.set_defaults(func=run_model_bench)

    args = parser.parse_args()
    args.func(args)
