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LithosAnanake/experiments
Robert Allan JamesandClaude Sonnet 5 dd09de65f5 FABRIC.md: item 4.5d -- arch_relax() tested against the PM Timer stall, disproven
Follow-up probing narrowed Finding 3's behavior (inconsistent stall point
run-to-run: sometimes reaches iters=1000/delta=951 before stopping,
sometimes never gets past iters=0 even after a 400-second bounded wait) but
didn't pin the mechanism.

Tested the strongest available hypothesis: single-threaded TCG scheduling
starvation from an -O2-tightened spin loop, based on a real precedent --
calibrate_apic_timer() (apic.c) already calls arch_relax() every iteration
of its own spin-wait; calibrate_tsc_with_pmtimer() never had it. Added the
same call, matching that precedent exactly. Result: no change, same exact
stall point on a fresh 60-second bounded wait. Reverted.

Stopping here per this document's own §25.0 rule 5 -- root-causing further
needs either deeper TCG/QEMU internals knowledge or a different diagnostic
approach (host-side instrumentation) than another guess-and-check pass.
Makefile.starkernel and timer.c both back to committed -O0 state, confirmed
booting clean.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-11 11:35:09 -04:00
..

experiments/

Design of Experiments (DoE) campaign data and analysis for the LithosAnanke kernel.

  • bare_metal/ — the bare-metal DoE experiment: blind full-factorial 2⁴ runs measuring the L8 Jacquard mode selector's effect on the Steady-State Machine across amd64/aarch64/riscv64. See experiments/bare_metal/README.md for the full directory layout (runs/, latest/, analysis/{charts,tables,report}).

Hosted-VM DoE campaigns (factorial/heartbeat/ablation studies) live under docs/working/experiments/ instead — this top-level directory is specifically the kernel/bare-metal side.