AI inference glossary
Agentic inference

Trace replay

Also known as workload replay, session replay

In plain English

Trace replay recreates the timing and shape of recorded sessions so a benchmark sends requests like the original workload.

Technical definition

Trace replay is a benchmarking method that converts recorded request relationships, lengths, and timing into a repeatable workload for a system under test.

Engineering details

A replay can preserve a directed graph of main-agent turns, parallel subagent branches, and auxiliary requests. Deterministic synthetic tokens replace private content while retaining token counts and prefix relationships. Recorded gaps between turns reproduce the periods when an agent was using tools or waiting on dependencies.

Why it matters

The method captures traffic features that a list of independent prompts cannot express. It also makes repeated hardware and software comparisons possible from the same session shapes. AgentX removes source-conversation content before publishing replay data.

How to read it in InferenceX

AgentX replays trace-derived sessions through AIPerf. A fixed seed selects sessions, starting points, and synthetic content. Reported results cover the profiling window after cache warmup, which keeps run-to-run comparisons focused on steady-state serving behavior.