1 files changed, 79 insertions, 0 deletions
diff --git a/research/experiments/030-app-lifecycle/memory.py b/research/experiments/030-app-lifecycle/memory.py
new file mode 100644
index 0000000..3c15d4a
--- /dev/null
+++ b/research/experiments/030-app-lifecycle/memory.py
@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+"""What changing an app leaves in a running host's memory (docs/design/017's
+stage 3, research 115). A host of apps holds an app of items.aup (a
+thousand items, its store in RAM); its own memory (smaps_rollup's
+Private_Dirty and Pss) is read after a warm-up of changes, then after
+CHANGES changes more: in place to another module (its line naming in turn
+items.pmod and items-next.pmod: each reading loads a module, and keeps the
+one it replaced), and with its module as it was (its queue budget changed
+in turn: no module loaded). The difference a change.
+
+memory.py PURE_SERVE CHANGES   a JSON line per way
+"""
+import json
+import select
+import shutil
+import signal
+import subprocess
+import sys
+import tempfile
+from pathlib import Path
+
+from window import AUP, HERE, grow
+
+
+def own(pid):
+    fields = {}
+    for line in Path(f'/proc/{pid}/smaps_rollup').read_text().splitlines()[1:]:
+        name, value = line.split(':', 1)
+        fields[name] = int(value.split()[0])
+    return fields['Private_Dirty'], fields['Pss']
+
+
+def main():
+    serve, changes = Path(sys.argv[1]).resolve(), int(sys.argv[2])
+    work = Path(tempfile.mkdtemp(prefix='pure-030-', dir='/dev/shm'))
+    try:
+        modules = {}
+        for name in ('items', 'items-next'):
+            modules[name] = work / f'{name}.pmod'
+            subprocess.run([str(AUP), 'build', str(HERE / f'{name}.aup'), '-o', str(modules[name])], check=True)
+        for way in ('module', 'budget'):
+            conf = work / 'apps.conf'
+
+            def write(n):
+                module = 'items-next' if way == 'module' and n % 2 else 'items'
+                budget = f' queue={1000 + n % 2}' if way == 'budget' else ''
+                conf.write_text(f"x {modules[module]} {work / way}{budget}\n")
+
+            write(0)
+            host = subprocess.Popen([str(serve), '--apps', str(conf), '--port', '0'], stdout=subprocess.PIPE,
+                                    stderr=subprocess.PIPE)
+            port = json.loads(host.stdout.readline())['port']
+            grow(port, 1000)
+
+            def change(n):
+                write(n)
+                host.send_signal(signal.SIGHUP)
+                ready, _, _ = select.select([host.stdout], [], [], 60)
+                assert ready
+                said = json.loads(host.stdout.readline())
+                assert said['apps'][0]['did'] == 'changed' and said['apps'][0]['running'], said
+
+            for n in range(1, 101):  # warm: the allocator's arenas settle
+                change(n)
+            dirty, pss = own(host.pid)
+            for n in range(101, 101 + changes):
+                change(n)
+            dirty_after, pss_after = own(host.pid)
+            host.terminate()
+            host.communicate(timeout=60)
+            print(json.dumps({'way': way, 'changes': changes, 'private_dirty_kib': [dirty, dirty_after],
+                              'pss_kib': [pss, pss_after],
+                              'per_change_bytes': round((dirty_after - dirty) * 1024 / changes)}), flush=True)
+    finally:
+        shutil.rmtree(work)
+
+
+if __name__ == '__main__':
+    main()