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, 4 insertions, 0 deletions

diff --git a/research/experiments/025-i64-cost/fcc1f67-interfered/2026-09-30-queries-before-6-linux-aarch64.jsonl b/research/experiments/025-i64-cost/fcc1f67-interfered/2026-09-30-queries-before-6-linux-aarch64.jsonl
new file mode 100644
index 0000000..0bfcc62
--- /dev/null
+++ b/research/experiments/025-i64-cost/fcc1f67-interfered/2026-09-30-queries-before-6-linux-aarch64.jsonl
@@ -0,0 +1,4 @@
+{"query": "per_branch", "rows": 10, "accounts": 100000, "pure_median_ms": 5.31, "pure_fastest_ms": 5.18, "sqlite_median_ms": 45.42, "sqlite_fastest_ms": 45.12, "sqlite_indexed_median_ms": 14.35, "sqlite_indexed_fastest_ms": 14.23}
+{"query": "in_credit", "rows": 1, "accounts": 100000, "pure_median_ms": 0.91, "pure_fastest_ms": 0.84, "sqlite_median_ms": 5.91, "sqlite_fastest_ms": 5.87, "sqlite_indexed_median_ms": 0.16, "sqlite_indexed_fastest_ms": 0.16}
+{"query": "large", "rows": 212, "accounts": 100000, "pure_median_ms": 0.48, "pure_fastest_ms": 0.41, "sqlite_median_ms": 1.49, "sqlite_fastest_ms": 1.47, "sqlite_indexed_median_ms": 1.93, "sqlite_indexed_fastest_ms": 1.65}
+{"query": "ranks", "rows": 404, "accounts": 100000, "pure_median_ms": 7.85, "pure_fastest_ms": 6.64, "sqlite_median_ms": 2842.07, "sqlite_fastest_ms": 2836.26, "sqlite_indexed_median_ms": 7.83, "sqlite_indexed_fastest_ms": 7.7}