[experimental chore/agentx-v0.2-aiperf-testing branch] agentic build_replay_cmd: --cache-bust system_prefix mismatched with current aiperf scenario (requires first_turn_prefix)

[andyluo7]

Summary

benchmarks/benchmark_lib.sh (function build_replay_cmd, around line 1000 of v0.2 tip) passes --cache-bust system_prefix to aiperf profile, but the current utils/aiperf submodule (70fecb2e) hardcodes first_turn_prefix as the only valid value for the inferencex-agentx-mvp scenario. The validation is fatal:

Value error, Scenario invariants violated (1 conflict):
- --cache-bust: got 'system_prefix', required 'first_turn_prefix'
(scenario 'inferencex-agentx-mvp' requires
 cache_bust.target=first_turn_prefix; got system_prefix)
Pass --unsafe-override to convert to warnings (run will be marked
submission_valid=false).

This is masked for short smoke runs because build_replay_cmd auto-adds --unsafe-override when DURATION < 900. Production sweep configs use DURATION=1800 and hit the error directly — the run flips to "invalid" or fails at validation, depending on flags.

Repro

# Any cpu/noffload sweep with DURATION=1800 (the production default)
podman run ... \
  -e MODEL=MiniMaxAI/MiniMax-M2.5 -e TP=4 -e CONC=16 \
  -e OFFLOADING=cpu -e TOTAL_CPU_DRAM_GB=1200 \
  -e DURATION=1800 \
  ... /workspace/benchmarks/single_node/agentic/minimaxm2.5_fp8_mi355x.sh

# vllm starts cleanly (Application startup complete, /health 200), then
# aiperf profile bails immediately with the validator error above.

Suggested fix

-    REPLAY_CMD+=" --cache-bust system_prefix"
+    REPLAY_CMD+=" --cache-bust first_turn_prefix"

…or, if backwards compat with older aiperf submodules matters, source the value from the scenario plugin via aiperf scenario describe inferencex-agentx-mvp and inject it dynamically.

After this patch, the full 30-min sweep runs cleanly (verified with both OFFLOADING=none and OFFLOADING=cpu, 11 + 8 conc points respectively, 0 launcher errors).

The launcher comment block at line 950 should also be updated — it currently says:

# The scenario plugin locks: --cache-bust system_prefix,

which became stale when the scenario validator was tightened.

Environment

• Branch: chore/agentx-v0.2-aiperf-testing (tip c8dfb585)
• aiperf submodule: 70fecb2e refactor(input): move --max-context-length filter into WekaTraceLoader

[functionstackx]

+viz @cquil11