Count instructions where timing cannot tell 3% apart (110)

016's second stage passed its criterion: six interleaved pairs against
ee21aec gave TPC-C (RAM, W=1) -0.6% at the median and the bank's
queries 0.0% to +2.2%, no run interfered. The ranks query was slower
all six times, and chasing it showed that on this Pi timing cannot
separate 1-3%: two servers asked in turns disagree with themselves
(ee21aec to e02bfc9 +1.6%, e02bfc9 to 481642f -1.2%, ee21aec to 481642f
+2.8%), and a query whose instructions grew 0.6% ran 3.5% faster.

Instructions do not move so: pcount.c counts the server's user-mode
instructions with perf_event_open (no perf here), and psample.c samples
where they go. ranks had grown 0.4% in instructions (the rest was where
code and data landed), per_branch 3.6% and tables 20 instructions a row,
which 07047c3 halved. The six pairs of 07047c3 were interfered (another
session's build, load 4-12) and are kept apart, unused.

1 files changed, 3 insertions, 0 deletions

diff --git a/research/experiments/025-i64-cost/fcc1f67-interfered/2026-09-30-tpcc-before-4-linux-aarch64.jsonl b/research/experiments/025-i64-cost/fcc1f67-interfered/2026-09-30-tpcc-before-4-linux-aarch64.jsonl
new file mode 100644
index 0000000..d5977ae
--- /dev/null
+++ b/research/experiments/025-i64-cost/fcc1f67-interfered/2026-09-30-tpcc-before-4-linux-aarch64.jsonl
@@ -0,0 +1,3 @@
+{"step": "load", "directory": "/dev/shm", "warehouses": 1, "rows": 568758, "generate_s": 0.58, "pure_load_s": 0.74, "sqlite_load_s": 1.57, "sqlite_page_size": 4096, "pure_resident_mib": 38.2, "sqlite_file_mib": 13.8}
+{"step": "run", "system": "pure", "warehouses": 1, "terminals": 64, "transactions_per_second": 39841, "new_orders_per_minute": 1066005, "undone_new_orders": 3417, "errors": 0, "new_order": {"done": 358754, "failed": 0, "p50_us": 1536, "p99_us": 4096}, "payment": {"done": 342430, "failed": 0, "p50_us": 1472, "p99_us": 4096}, "order_status": {"done": 32010, "failed": 0, "p50_us": 272, "p99_us": 2048}, "delivery": {"done": 31934, "failed": 0, "p50_us": 1472, "p99_us": 4096}, "stock_level": {"done": 31688, "failed": 0, "p50_us": 304, "p99_us": 2176}, "server_threads": "3", "cpu_us_per_transaction": 45.3, "core_shares": {"pure-owner": 0.83, "pure-checkpoint": 0.01}, "resident_mib": 423.8, "written_bytes_per_transaction": 0.0, "device_bytes_per_transaction": null, "consistency_failures": []}
+{"step": "end", "pure_resident_mib": 423.8, "pure_state_mib": 214.2, "pure_store_mib": 222.7, "sqlite_files_mib": 13.8, "grouped_sqlite_files_mib": 0.0, "pure_counts": {"bursts": 25506, "burst_events": 729779, "checkpoints": 36}}