FAST25-release

Mooncake FAST'25 Trace Release

This directory contains the open-source request traces associated with Mooncake.

The traces/ directory is the updated trace release used by the FAST'25 paper. The older arxiv-trace/mooncake_trace.jsonl file is the historical single-file trace release from the arXiv technical report.

Directory Layout

Path	Description
traces/conversation_trace.jsonl	FAST'25 conversation workload trace.
traces/toolagent_trace.jsonl	FAST'25 tool and agent workload trace.
traces/synthetic_trace.jsonl	FAST'25 synthetic workload trace built from public datasets.
arxiv-trace/mooncake_trace.jsonl	Historical trace released with the arXiv technical report.
Mooncake-FAST25.pdf	FAST'25 paper with the trace appendix.

For new experiments that reproduce or build on the FAST'25 paper, prefer the three files under traces/. Use arxiv-trace/mooncake_trace.jsonl when referring to the original arXiv technical report trace or comparing against the earlier single-file trace release.

Workloads

The FAST'25 trace release contains three workloads:

Workload	File	Requests	Avg input length	Avg output length	Arrival pattern
Conversation	traces/conversation_trace.jsonl	12,031	12,035	343	Timestamp
Tool and Agent	traces/toolagent_trace.jsonl	23,608	8,596	182	Timestamp
Synthetic	traces/synthetic_trace.jsonl	3,993	15,325	149	Poisson

The conversation and tool and agent traces are sampled from one hour of online request data. The synthetic trace is constructed from public datasets and uses Poisson-generated arrivals while preserving the order within multi-turn conversations.

Trace Format

Each trace is a JSONL file. Each line is one request:

{
    "timestamp": 27482,
    "input_length": 6955,
    "output_length": 52,
    "hash_ids": [46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 2353, 2354]
}
{
    "timestamp": 30535,
    "input_length": 6472,
    "output_length": 26,
    "hash_ids": [46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 2366]
}

Fields:

• timestamp: Relative request arrival time in milliseconds. In the real traces, requests should be replayed according to these timestamps. In the synthetic trace, timestamps are generated from a Poisson process.
• input_length: Number of input tokens. Raw text and tokens are not included for privacy protection.
• output_length: Number of output tokens.
• hash_ids: Remapped prefix block hashes. The block size is 512 tokens. Identical hash IDs indicate reusable prefix KV cache blocks. For example, the two sample requests share the first 12 hash IDs, so they can share prefix caching for the first 12 * 512 = 6144 tokens.

The trace files contain only anonymized timing, length, and remapped hash information. They are intended for reproducible simulation and evaluation of KV cache reuse behavior without exposing user content.

For more details, see the FAST'25 paper appendix in Mooncake-FAST25.pdf.