Say what a transient state saves a write (018 stage 1, research 117)

3 files changed, 87 insertions, 0 deletions

diff --git a/research/experiments/032-transient-states/2026-10-04-ram.jsonl b/research/experiments/032-transient-states/2026-10-04-ram.jsonl
new file mode 100644
index 0000000..0a87923
--- /dev/null
+++ b/research/experiments/032-transient-states/2026-10-04-ram.jsonl
@@ -0,0 +1,7 @@
+{"medium": "ram", "round": 1, "way": "stored", "written_per_request": 0.0, "requests_per_second": 132446, "completed": 1324463, "2xx": 1324463, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 116, "p99_us": 144, "max_us": 6656}
+{"medium": "ram", "round": 1, "way": "transient", "written_per_request": 0.0, "requests_per_second": 131252, "completed": 1312517, "2xx": 1312517, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 116, "p99_us": 152, "max_us": 8192}
+{"medium": "ram", "round": 2, "way": "transient", "written_per_request": 0.0, "requests_per_second": 132522, "completed": 1325225, "2xx": 1325225, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 116, "p99_us": 144, "max_us": 4608}
+{"medium": "ram", "round": 2, "way": "stored", "written_per_request": 0.0, "requests_per_second": 128044, "completed": 1280441, "2xx": 1280441, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 120, "p99_us": 184, "max_us": 6144}
+{"medium": "ram", "round": 3, "way": "stored", "written_per_request": 0.0, "requests_per_second": 130576, "completed": 1305763, "2xx": 1305763, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 120, "p99_us": 152, "max_us": 5888}
+{"medium": "ram", "round": 3, "way": "transient", "written_per_request": 0.0, "requests_per_second": 133163, "completed": 1331634, "2xx": 1331634, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 116, "p99_us": 144, "max_us": 3968}
+{"medium": "ram", "stored_median": 130576, "transient_median": 132522, "change": 1.5, "written_per_request": {"stored": 0.0, "transient": 0.0}}
diff --git a/research/experiments/032-transient-states/2026-10-04-sd.jsonl b/research/experiments/032-transient-states/2026-10-04-sd.jsonl
new file mode 100644
index 0000000..0f55fbe
--- /dev/null
+++ b/research/experiments/032-transient-states/2026-10-04-sd.jsonl
@@ -0,0 +1,7 @@
+{"medium": "sd", "round": 1, "way": "stored", "written_per_request": 1032.9, "requests_per_second": 7598, "completed": 75981, "2xx": 75981, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 1600, "p99_us": 7168, "max_us": 59392}
+{"medium": "sd", "round": 1, "way": "transient", "written_per_request": 0.0, "requests_per_second": 129617, "completed": 1296169, "2xx": 1296169, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 116, "p99_us": 168, "max_us": 11776}
+{"medium": "sd", "round": 2, "way": "transient", "written_per_request": 0.0, "requests_per_second": 132888, "completed": 1328882, "2xx": 1328882, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 116, "p99_us": 136, "max_us": 5120}
+{"medium": "sd", "round": 2, "way": "stored", "written_per_request": 1032.9, "requests_per_second": 7513, "completed": 75137, "2xx": 75137, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 1536, "p99_us": 7168, "max_us": 106496}
+{"medium": "sd", "round": 3, "way": "stored", "written_per_request": 1033.4, "requests_per_second": 7601, "completed": 76193, "2xx": 76193, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 1536, "p99_us": 7168, "max_us": 59392}
+{"medium": "sd", "round": 3, "way": "transient", "written_per_request": 0.0, "requests_per_second": 132305, "completed": 1323051, "2xx": 1323051, "4xx": 0, "5xx": 0, "errors": 0, "p50_us": 116, "p99_us": 152, "max_us": 4096}
+{"medium": "sd", "stored_median": 7598, "transient_median": 132305, "change": 1641.3, "written_per_request": {"stored": 1032.9, "transient": 0.0}}
diff --git a/research/experiments/032-transient-states/transient.py b/research/experiments/032-transient-states/transient.py
new file mode 100755
index 0000000..87153c8
--- /dev/null
+++ b/research/experiments/032-transient-states/transient.py
@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+"""What a transient state saves (docs/design/018 stage 1, research 117). A
+host of apps (one connection thread, two workers, cores 0-2) holds the
+scoreboard (benchmarks/http/scores.aup) twice: stored, as it is, and
+transient, its board a transient state. The load (benchmarks/http/load,
+core 3) posts points for SECONDS on CONNECTIONS connections, keep-alive, to
+one of them; the two in turns, their order turned each round. The stores
+are in RAM (/dev/shm) or on the SD card (~/.cache). Each run says what the
+host wrote to the device meanwhile (/proc/PID/io write_bytes).
+
+transient.py PURE_SERVE ram|sd SECONDS ROUNDS   a JSON line per run, then medians
+"""
+import json
+import shutil
+import statistics
+import subprocess
+import sys
+import tempfile
+from pathlib import Path
+
+HERE = Path(__file__).resolve().parent
+ROOT = HERE.parents[2]
+AUP = ROOT.parent / 'aup' / 'build' / 'aup'
+LOAD = ROOT / 'benchmarks' / 'http' / 'load'
+
+
+def written(pid):
+    for line in Path(f'/proc/{pid}/io').read_text().splitlines():
+        if line.startswith('write_bytes:'):
+            return int(line.split()[1])
+
+
+def main():
+    serve, medium, seconds, rounds = Path(sys.argv[1]).resolve(), sys.argv[2], int(sys.argv[3]), int(sys.argv[4])
+    base = Path('/dev/shm') if medium == 'ram' else Path.home() / '.cache'
+    base.mkdir(parents=True, exist_ok=True)
+    work = Path(tempfile.mkdtemp(prefix='pure-032-', dir=base))
+    try:
+        source = (ROOT / 'benchmarks' / 'http' / 'scores.aup').read_text()
+        (work / 'transient.aup').write_text(source.replace('state board', 'transient state board'))
+        for name, path in (('stored', ROOT / 'benchmarks' / 'http' / 'scores.aup'), ('transient', work / 'transient.aup')):
+            subprocess.run([str(AUP), 'build', str(path), '-o', str(work / f'{name}.pmod')], check=True)
+        (work / 'apps.conf').write_text(f"stored {work / 'stored.pmod'} {work / 'stored'}\n"
+                                        f"transient {work / 'transient.pmod'} {work / 'transient'}\n")
+        host = subprocess.Popen(['taskset', '-c', '0-2', str(serve), '--apps', str(work / 'apps.conf'), '--port', '0',
+                                 '--threads', '1', '--workers', '2'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        port = json.loads(host.stdout.readline())['port']
+        rates, bytes_ = {}, {}
+        for round_ in range(1, rounds + 1):
+            ways = ['stored', 'transient']
+            for way in (ways if round_ % 2 else ways[::-1]):
+                before = written(host.pid)
+                out = subprocess.run(['taskset', '-c', '3', str(LOAD), str(port), '16', str(seconds), 'score', '64',
+                                      'keep-alive', '16', f'/{way}'], capture_output=True, text=True, check=True).stdout
+                result = json.loads(out)
+                assert result['2xx'] == result['completed'] and not result['errors'], result
+                per = (written(host.pid) - before) / result['completed']
+                rates.setdefault(way, []).append(result['requests_per_second'])
+                bytes_.setdefault(way, []).append(per)
+                print(json.dumps({'medium': medium, 'round': round_, 'way': way, 'written_per_request': round(per, 1),
+                                  **result}), flush=True)
+        host.terminate()
+        host.communicate(timeout=60)
+        stored, transient = statistics.median(rates['stored']), statistics.median(rates['transient'])
+        print(json.dumps({'medium': medium, 'stored_median': stored, 'transient_median': transient,
+                          'change': round((transient / stored - 1) * 100, 1),
+                          'written_per_request': {w: round(statistics.median(bytes_[w]), 1) for w in bytes_}}), flush=True)
+    finally:
+        shutil.rmtree(work)
+
+
+if __name__ == '__main__':
+    main()