CP shared KV and HiCache now use owner-lane metadata as the authoritative capacity view for host write admission and GPU load-back planning. This removes the debug scalar capacity env and keeps CP load-back from relying on a rank-wide scalar collective when per-owner availability is already known. The load-back planner also accounts for evicting child leaves that unlock ancestor device residency, which fixes small lane deficits despite large aggregate evictable capacity. The commit also adds gated CPU timing logs for CP shared-KV MLA/index prefetch and a CUDA microbenchmark for comparing dense all-reduce with owner-packed all-gather layouts. The timing logs are intentionally behind the existing MLA prefetch log env and should not be enabled for throughput measurements. Constraint: CP shared KV owner lanes require target/draft capacity decisions to preserve page_owners rather than total-token scalars Constraint: CUDA collective benchmarks must run on target GPU hosts, not locally Rejected: Keep SGLANG_CP_HICACHE_CAPACITY_DEBUG observer env | owner-lane admission now replaces that scalar debug path Rejected: Add a silent scalar-allreduce fallback | unexpected owner-lane mismatch should fail fast or log loudly Confidence: medium Scope-risk: moderate Directive: Do not reintroduce CP capacity collectives on the scheduler hot path without proving the owner-lane metadata is insufficient Directive: Disable SGLANG_CP_SHARED_KV_LOG_MLA_PREFETCH for end-to-end performance runs; it is diagnostic and high-volume Tested: git diff --check Tested: python -m py_compile on changed runtime/test/benchmark Python files Tested: remote pytest -q test/registered/unit/mem_cache/test_cp_hicache_load_back_owner_lanes.py test/registered/unit/mem_cache/test_cp_hicache_metadata.py (81 passed, 5 warnings) Not-tested: CUDA benchmark benchmark/hicache/bench_cp_shared_kv_prefetch_collective.py Not-tested: full GLM5 E2E throughput after this commit
Run synthetic multi-turn benchmark
# SGLang server with radix cache disabled
python -m sglang.launch_server --model-path Qwen/Qwen2.5-14B-Instruct --port 30000 --disable-radix-cache
# SGLang server with radix cache on and first-come-first-serve policy
python -m sglang.launch_server --model-path Qwen/Qwen2.5-14B-Instruct --port 30000 --schedule-policy fcfs
# The default SGLang server with radix cache on and long-prefix-match policy
python -m sglang.launch_server --model-path Qwen/Qwen2.5-14B-Instruct --port 30000
# SGLang server with hierarchical radix cache enabled
python -m sglang.launch_server --model-path Qwen/Qwen2.5-14B-Instruct --port 30000 --enable-hierarchical-cache
python bench_multiturn.py --model-path Qwen/Qwen2.5-14B-Instruct
Note: The performance gain of hierarchical caching depends on the ratio of reusable tokens to GPU memory capacity. The more tokens to be reused, the larger the model, and the more constrained the GPU memory size, the greater the benefit one can expect from hierarchical caching.
Benchmark with more datasets
Download Dataset
./download.sh {sharegpt|ultragpt|loogle|nextqa|all}
This script will automatically download the required dataset to the current working directory
Multiturn Benchmark
Supported Datasets
- sharegpt
- ultrachat
- loogle
Example Usage:
python3 bench_serving.py --model mistralai/Mistral-7B-Instruct-v0.3 --backend sglang \
--dataset-path longdep_qa.json --dataset-name loogle --request-rate 10 --num-prompts 10 \
--port 8001 --enable-multiturn --disable-shuffle
This uses mistralai/Mistral-7B-Instruct-v0.3 model with sglang as backend. The dataset
is longdep_qa.json. We send 10 conversations with 10 req/s to port 8001. We enable
multiturn chat without shuffling the order of conversations (i.e. following the original
order in the dataset file).
Note:
The requests of multiple conversations are sent in a round robin fashion.
For example, if we have 3 conversations A, B, C whose rounds are [2, 3, 4] correspondingly,
multiturn chat will send the requests to the backend in the following order: [A1, B1, C1, A2, B2, C2, B3, C3, C4]
This has implications on the cache reuse patterns: the cache reuse distance is the largest
under this request pattern (which means a prefix-aware local scheduler in the backend can
yield the most benefit compared to a FIFO scheduler)
Shared Prefix Benchmark
Supported Datasets
- loogle
Example Usage:
python3 bench_serving.py --model mistralai/Mistral-7B-Instruct-v0.3 --backend sglang \
--dataset-path longdep_qa.json --dataset-name loogle --request-rate 10 --num-prompts 10 \
--port 8001 --enable-shared-prefix --disable-shuffle
Note:
Shared Prefix benchmark sends the questions for the same prompt together. For example,
if we have 3 shared prefix A, B, C, which have [2, 3, 4] questions correspondingly,
the shared prefix benchmark will send the requests to the
backend in the following order: [A+Q1, A+Q2, B+Q1, B+Q2, B+Q3, C+Q1, C+Q2, C+Q3].
Multi Modality Benchmark (WIP)
Supported Datasets:
- nextqa
Example Usage:
Server:
python3 -m sglang.launch_server --model-path lmms-lab/LLaVA-NeXT-Video-7B --tp 2 --dp 1 --port 8001 \
--host 0.0.0.0 --mem-fraction-static 0.9 --tokenizer-path llava-hf/llava-1.5-7b-hf \
--json-model-override-args "{\"architectures\": [\"LlavaVidForCausalLM\"], \"model_type\":\"llava\", \"mm_spatial_pool_stride\":2}"
Client:
python3 bench_serving.py --model lmms-lab/LLaVA-NeXT-Video-7B --backend sglang --dataset-path \
NExTVideo --dataset-name nextqa --request-rate 10 --num-prompts 1 --disable-shuffle --port 8001 \ --enable-multiturn --max-frames 16 --tokenizer llava-hf/llava-1.5-7b-hf --fixed-output-len 2048
Note: for the server args, tokenizer-path, overriding architecture are necessary.
Supported Backend
- sglang (oai)
- vllm (oai)
- lmdeploy (oai)