[kernel optimize] benchmark write_req_to_token_pool_triton and optimize kernel (#2509)

benchmark/kernels/scheduler_batch/benchmark_write_req_to_token_pool_triton.py

+import itertools
+import os
+from typing import List
+
+import numpy as np
+import pytest
+import torch
+import triton
+import triton.language as tl
+
+
+@triton.jit
+def write_req_to_token_pool_triton(
+    req_to_token_ptr,  # [max_batch, max_context_len]
+    req_pool_indices,
+    pre_lens,
+    seq_lens,
+    extend_lens,
+    out_cache_loc,
+    req_to_token_ptr_stride: tl.constexpr,
+):
+    BLOCK_SIZE: tl.constexpr = 512
+    pid = tl.program_id(0)
+
+    req_pool_index = tl.load(req_pool_indices + pid)
+    pre_len = tl.load(pre_lens + pid)
+    seq_len = tl.load(seq_lens + pid)
+
+    # TODO: optimize this?
+    cumsum_start = 0
+    for i in range(pid):
+        cumsum_start += tl.load(extend_lens + i)
+
+    num_loop = tl.cdiv(seq_len - pre_len, BLOCK_SIZE)
+    for i in range(num_loop):
+        offset = tl.arange(0, BLOCK_SIZE) + i * BLOCK_SIZE
+        mask = offset < (seq_len - pre_len)
+        value = tl.load(out_cache_loc + cumsum_start + offset, mask=mask)
+        tl.store(
+            req_to_token_ptr
+            + req_pool_index * req_to_token_ptr_stride
+            + offset
+            + pre_len,
+            value,
+            mask=mask,
+        )
+
+
+@triton.jit
+def write_req_to_token_pool_triton_optimize(
+    req_to_token_ptr,  # [max_batch, max_context_len]
+    req_pool_indices,
+    pre_lens,
+    seq_lens,
+    extend_lens,
+    out_cache_loc,
+    req_to_token_ptr_stride: tl.constexpr,
+    BLOCK_SIZE: tl.constexpr,
+):
+    pid_batch = tl.program_id(0)
+    pid_token = tl.program_id(1)
+
+    req_pool_index = tl.load(req_pool_indices + pid_batch)
+    pre_len = tl.load(pre_lens + pid_batch)
+    seq_len = tl.load(seq_lens + pid_batch)
+    extend_len = seq_len - pre_len
+
+    cumsum_start = 0
+    for i in range(pid_batch):
+        cumsum_start += tl.load(extend_lens + i)
+
+    token_start = pid_token * BLOCK_SIZE
+
+    offset = tl.arange(0, BLOCK_SIZE)
+    actual_offset = token_start + offset
+    mask = actual_offset < extend_len
+
+    src_ptr = out_cache_loc + cumsum_start + actual_offset
+    src_ptr = tl.max_contiguous(tl.multiple_of(src_ptr, BLOCK_SIZE), BLOCK_SIZE)
+    value = tl.load(src_ptr, mask=mask)
+    dst_ptr = (
+        req_to_token_ptr
+        + req_pool_index * req_to_token_ptr_stride
+        + actual_offset
+        + pre_len
+    )
+    dst_ptr = tl.max_contiguous(tl.multiple_of(dst_ptr, BLOCK_SIZE), BLOCK_SIZE)
+
+    tl.store(dst_ptr, value, mask=mask)
+
+
+def write_req_to_token_pool_reference(
+    req_to_token: torch.Tensor,
+    req_pool_indices: torch.Tensor,
+    pre_lens: torch.Tensor,
+    seq_lens: torch.Tensor,
+    extend_lens: torch.Tensor,
+    out_cache_loc: torch.Tensor,
+) -> None:
+    """Reference implementation using PyTorch"""
+    for i in range(len(req_pool_indices)):
+        req_pool_idx = req_pool_indices[i].item()
+        pre_len = pre_lens[i].item()
+        seq_len = seq_lens[i].item()
+        extend_len = extend_lens[i].item()
+
+        cumsum_start = sum(extend_lens[:i].tolist())
+
+        # Copy values from out_cache_loc to req_to_token
+        req_to_token[req_pool_idx, pre_len:seq_len] = out_cache_loc[
+            cumsum_start : cumsum_start + extend_len
+        ]
+
+
+def test_write_req_to_token_pool():
+    max_batch = 4097
+    max_context_len = 6148
+    batch_size = 1
+    extend_len = 14
+
+    # Initialize input tensors
+    req_to_token = torch.zeros(
+        (max_batch, max_context_len), dtype=torch.int32, device="cuda"
+    )
+    req_pool_indices = torch.tensor([42], dtype=torch.int32, device="cuda")
+    pre_lens = torch.tensor([8], dtype=torch.int32, device="cuda")
+    seq_lens = torch.tensor([22], dtype=torch.int32, device="cuda")
+    extend_lens = torch.tensor([extend_len], dtype=torch.int32, device="cuda")
+    out_cache_loc = torch.arange(extend_len, dtype=torch.int32, device="cuda")
+
+    # Create copies for reference implementation
+    req_to_token_ref = req_to_token.clone()
+    req_to_token_opt = req_to_token.clone()
+
+    # Run original triton kernel
+    write_req_to_token_pool_triton[(batch_size,)](
+        req_to_token,
+        req_pool_indices,
+        pre_lens,
+        seq_lens,
+        extend_lens,
+        out_cache_loc,
+        max_context_len,
+    )
+
+    # Run optimized triton kernel
+    def grid(batch_size, extend_len):
+        num_token_blocks = triton.cdiv(extend_len, 512)
+        return (batch_size, num_token_blocks)
+
+    write_req_to_token_pool_triton_optimize[grid(batch_size, extend_len)](
+        req_to_token_opt,
+        req_pool_indices,
+        pre_lens,
+        seq_lens,
+        extend_lens,
+        out_cache_loc,
+        max_context_len,
+        BLOCK_SIZE=512,
+    )
+
+    # Run reference implementation
+    write_req_to_token_pool_reference(
+        req_to_token_ref,
+        req_pool_indices,
+        pre_lens,
+        seq_lens,
+        extend_lens,
+        out_cache_loc,
+    )
+
+    # Compare results
+    torch.testing.assert_close(req_to_token, req_to_token_ref)
+    torch.testing.assert_close(req_to_token_opt, req_to_token_ref)
+
+    # Test case 2: batch size > 1
+    batch_size = 3
+    extend_lens_list = [14, 20, 30]
+    total_extend_len = sum(extend_lens_list)
+
+    req_to_token = torch.zeros(
+        (max_batch, max_context_len), dtype=torch.int32, device="cuda"
+    )
+    req_pool_indices = torch.tensor([42, 100, 200], dtype=torch.int32, device="cuda")
+    pre_lens = torch.tensor([8, 10, 15], dtype=torch.int32, device="cuda")
+    seq_lens = torch.tensor([22, 30, 45], dtype=torch.int32, device="cuda")
+    extend_lens = torch.tensor(extend_lens_list, dtype=torch.int32, device="cuda")
+    out_cache_loc = torch.arange(total_extend_len, dtype=torch.int32, device="cuda")
+
+    req_to_token_ref = req_to_token.clone()
+    req_to_token_opt = req_to_token.clone()
+
+    # Run original triton kernel
+    write_req_to_token_pool_triton[(batch_size,)](
+        req_to_token,
+        req_pool_indices,
+        pre_lens,
+        seq_lens,
+        extend_lens,
+        out_cache_loc,
+        max_context_len,
+    )
+
+    # Run optimized triton kernel
+    max_extend_len = max(extend_lens_list)
+    write_req_to_token_pool_triton_optimize[grid(batch_size, max_extend_len)](
+        req_to_token_opt,
+        req_pool_indices,
+        pre_lens,
+        seq_lens,
+        extend_lens,
+        out_cache_loc,
+        max_context_len,
+        BLOCK_SIZE=512,
+    )
+
+    # Run reference implementation
+    write_req_to_token_pool_reference(
+        req_to_token_ref,
+        req_pool_indices,
+        pre_lens,
+        seq_lens,
+        extend_lens,
+        out_cache_loc,
+    )
+
+    # Compare results
+    torch.testing.assert_close(req_to_token, req_to_token_ref)
+    torch.testing.assert_close(req_to_token_opt, req_to_token_ref)
+
+
+def get_benchmark():
+    batch_sizes = [1, 2, 4, 8, 16, 32, 64, 128]
+    extend_lens = [32, 64, 128, 256, 512, 1024, 2048, 4096, 8192]
+    configs = list(itertools.product(batch_sizes, extend_lens))
+
+    @triton.testing.perf_report(
+        triton.testing.Benchmark(
+            x_names=["batch_size", "extend_len"],
+            x_vals=configs,
+            line_arg="provider",
+            line_vals=["reference", "triton", "triton_optimize"],
+            line_names=["PyTorch", "Triton", "Triton Optimized"],
+            styles=[("blue", "-"), ("green", "-"), ("red", "-")],
+            ylabel="us",
+            plot_name="write-req-to-token-pool-performance",
+            args={},
+        )
+    )
+    def benchmark(batch_size, extend_len, provider):
+        max_batch = 256
+        max_context_len = 16384
+
+        extend_lens_list = [extend_len] * batch_size
+        total_extend_len = sum(extend_lens_list)
+
+        req_to_token = torch.zeros(
+            (max_batch, max_context_len), dtype=torch.int32, device="cuda"
+        )
+        req_pool_indices = torch.arange(batch_size, dtype=torch.int32, device="cuda")
+        pre_lens = torch.ones(batch_size, dtype=torch.int32, device="cuda") * 8
+        seq_lens = pre_lens + extend_len
+        extend_lens = torch.tensor(extend_lens_list, dtype=torch.int32, device="cuda")
+        out_cache_loc = torch.arange(total_extend_len, dtype=torch.int32, device="cuda")
+
+        quantiles = [0.5, 0.2, 0.8]
+
+        if provider == "reference":
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                lambda: write_req_to_token_pool_reference(
+                    req_to_token.clone(),
+                    req_pool_indices,
+                    pre_lens,
+                    seq_lens,
+                    extend_lens,
+                    out_cache_loc,
+                ),
+                quantiles=quantiles,
+            )
+        elif provider == "triton":
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                lambda: write_req_to_token_pool_triton[(batch_size,)](
+                    req_to_token.clone(),
+                    req_pool_indices,
+                    pre_lens,
+                    seq_lens,
+                    extend_lens,
+                    out_cache_loc,
+                    max_context_len,
+                ),
+                quantiles=quantiles,
+            )
+        else:
+
+            def run_optimized():
+                block_size = 128 if extend_len <= 1024 else 512
+                grid_config = (batch_size, triton.cdiv(extend_len, block_size))
+                write_req_to_token_pool_triton_optimize[grid_config](
+                    req_to_token.clone(),
+                    req_pool_indices,
+                    pre_lens,
+                    seq_lens,
+                    extend_lens,
+                    out_cache_loc,
+                    max_context_len,
+                    BLOCK_SIZE=block_size,
+                )
+
+            ms, min_ms, max_ms = triton.testing.do_bench(
+                run_optimized, quantiles=quantiles
+            )
+
+        return 1000 * ms, 1000 * max_ms, 1000 * min_ms
+
+    return benchmark
+
+
+def run_benchmark(save_path: str = "./configs/benchmark_ops/write_req_to_token_pool/"):
+    """Run benchmark and save results"""
+
+    # Ensure save path exists
+    os.makedirs(save_path, exist_ok=True)
+
+    # Run correctness test
+    test_write_req_to_token_pool()
+    print("Correctness test passed!")
+
+    # Run performance test
+    benchmark = get_benchmark()
+    benchmark.run(print_data=True, save_path=save_path)
+
+
+if __name__ == "__main__":
+    import argparse
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--save_path",
+        type=str,
+        default="./configs/benchmark_ops/write_req_to_token_pool/",
+        help="Path to save benchmark results",
+    )
+    args = parser.parse_args()
+
+    run_benchmark(args.save_path)