Establish native micro runtime checkpoint

1 files changed, 139 insertions, 0 deletions

diff --git a/research/experiments/006-native-save-latency/measure.py b/research/experiments/006-native-save-latency/measure.py
new file mode 100644
index 0000000..f1e2a00
--- /dev/null
+++ b/research/experiments/006-native-save-latency/measure.py
@@ -0,0 +1,139 @@
+#!/usr/bin/env python3
+"""Time durable one-byte saves in the actual native terminal document app."""
+import argparse
+import fcntl
+import hashlib
+import json
+import os
+from pathlib import Path
+import platform
+import pty
+import select
+import statistics
+import struct
+import subprocess
+import tempfile
+import termios
+import time
+
+
+def run(*args):
+    return subprocess.run([str(arg) for arg in args], check=True,
+                          capture_output=True, timeout=30)
+
+
+def frame(master, process):
+    output = bytearray()
+    deadline = time.monotonic() + 15
+    while time.monotonic() < deadline:
+        if select.select([master], [], [], 0.5)[0]:
+            output.extend(os.read(master, 65536))
+            if b'\x1b[?25h' in output:
+                return bytes(output)
+        if process.poll() is not None:
+            break
+    raise AssertionError((process.poll(), output[-1000:]))
+
+
+def one_session(cli, tui, root, size, iterations):
+    root.mkdir(parents=True)
+    store = root / 'store'
+    body = b'A' * size
+    insert = root / 'initial.bin'
+    insert.write_bytes(body)
+    assert json.loads(run(cli, '--store', store, 'edit', 'document',
+                          0, 0, 0, insert).stdout)['revision'] == '1'
+    master, slave = pty.openpty()
+    fcntl.ioctl(slave, termios.TIOCSWINSZ, struct.pack('HHHH', 24, 80, 0, 0))
+    original = termios.tcgetattr(slave)
+    process = subprocess.Popen([str(tui), '--store', str(store), 'document'],
+                               stdin=slave, stdout=slave, stderr=slave,
+                               env={**os.environ, 'LANG': 'C.UTF-8', 'LC_ALL': 'C.UTF-8'})
+    samples = []
+    try:
+        assert b'Pure | document' in frame(master, process)
+        for index in range(iterations):
+            replacement = b'B' if index % 2 == 0 else b'A'
+            os.write(master, b'\x7f')
+            frame(master, process)
+            os.write(master, replacement)
+            frame(master, process)
+            start = time.perf_counter_ns()
+            os.write(master, b'\x13')
+            shown = frame(master, process)
+            elapsed = time.perf_counter_ns() - start
+            expected = f'Saved 1-byte edit at byte {size - 1}'.encode()
+            revision = f'revision {index + 2}'.encode()
+            assert expected in shown and revision in shown, shown[-1500:]
+            samples.append(elapsed)
+        os.write(master, b'\x11')
+        process.wait(timeout=8)
+        assert process.returncode == 0
+        assert termios.tcgetattr(slave) == original
+    finally:
+        if process.poll() is None:
+            process.kill()
+            process.wait(timeout=5)
+        os.close(master)
+        os.close(slave)
+    final = run(cli, '--store', store, 'show', 'document')
+    expected_body = body[:-1] + (b'B' if iterations % 2 else b'A')
+    assert final.stdout == expected_body
+    assert json.loads(final.stderr)['revision'] == str(iterations + 1)
+    return {'samples_ns': samples, 'median_ns': int(statistics.median(samples)),
+            'final_revision': iterations + 1,
+            'body_sha256': hashlib.sha256(final.stdout).hexdigest()}
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--flat-cli', type=Path, required=True)
+    parser.add_argument('--flat-tui', type=Path, required=True)
+    parser.add_argument('--paged-cli', type=Path, required=True)
+    parser.add_argument('--paged-tui', type=Path, required=True)
+    parser.add_argument('--scratch-parent', type=Path, required=True)
+    parser.add_argument('--rounds', type=int, default=3)
+    parser.add_argument('--edits', type=int, default=8)
+    parser.add_argument('--output', type=Path)
+    args = parser.parse_args()
+    if args.rounds < 1 or args.edits < 1 or (args.output and args.output.exists()):
+        parser.error('rounds and edits must be positive; output must not exist')
+    binaries = {name: (cli.resolve(), tui.resolve()) for name, cli, tui in
+                (('flat', args.flat_cli, args.flat_tui),
+                 ('paged', args.paged_cli, args.paged_tui))}
+    parent = args.scratch_parent.resolve()
+    parent.mkdir(parents=True, exist_ok=True)
+    filesystem = run('findmnt', '-T', parent, '-no', 'SOURCE,FSTYPE').stdout.decode().strip()
+    raw = {name: {'256': [], '1048576': []} for name in binaries}
+    with tempfile.TemporaryDirectory(prefix='pure-native-save-', dir=parent) as directory:
+        root = Path(directory)
+        for size in (256, 1_048_576):
+            for round_number in range(args.rounds):
+                order = ('flat', 'paged') if round_number % 2 == 0 else ('paged', 'flat')
+                for name in order:
+                    cli, tui = binaries[name]
+                    raw[name][str(size)].append(one_session(
+                        cli, tui, root / f'{size}-{round_number}-{name}', size, args.edits))
+    result = {'platform': platform.platform(), 'filesystem': filesystem,
+              'workload': 'one-byte final-character replacement, Ctrl+S to complete visible frame; '
+                          'includes full draft comparison, runtime, durable store and redraw; '
+                          'initial creation and final independent CLI read excluded',
+              'rounds': args.rounds, 'edits_per_session': args.edits,
+              'binaries': {name: {'cli_sha256': hashlib.sha256(cli.read_bytes()).hexdigest(),
+                                  'tui_sha256': hashlib.sha256(tui.read_bytes()).hexdigest()}
+                           for name, (cli, tui) in binaries.items()},
+              'runs': raw,
+              'median_ns': {name: {size: int(statistics.median(
+                  sample for session in sessions for sample in session['samples_ns']))
+                  for size, sessions in sizes.items()} for name, sizes in raw.items()}}
+    encoded = json.dumps(result, indent=2) + '\n'
+    if args.output:
+        args.output.parent.mkdir(parents=True, exist_ok=True)
+        args.output.write_text(encoded)
+    print(json.dumps({'platform': result['platform'], 'filesystem': filesystem,
+                      'median_ns': result['median_ns'], 'rounds': args.rounds,
+                      'edits_per_session': args.edits}))
+
+
+if __name__ == '__main__':
+    main()