fix: delay client compression until game focus (#1406)

tools/linuxfs/overlay/usr/local/bin/droiddeck-session

@@ -466,16 +466,32 @@ case $mode in
       esac
       (
         bl_zram_scan() {
-          _bl_game=0 _bl_pids=() _bl_others=()
+          _bl_game=0 _bl_pids=() _bl_others=() _bl_apps=
+          local _d _c _args _name _a _id
           for _d in /proc/[0-9]*; do
-            [ "${_d#/proc/}" != "$BASHPID" ] || continue
-            # Under FEX the program is FEX's first argument.
-            { IFS= read -r -d '' _c && case ${_c##*/} in FEX|FEXInterpreter) IFS= read -r -d '' _c ;; esac; } \
-              2>/dev/null < "$_d/cmdline" || continue
-            case ${_c##*/} in
-              reaper) _bl_game=1 ;;
-              steam|steamwebhelper) _bl_pids+=("${_d#/proc/}") ;;
-              *) _bl_others+=("${_d#/proc/}") ;;
+            [ "${_d##*/}" != "$BASHPID" ] || continue
+            _args=()
+            # Under FEX the program is FEX's first argument. AppId= is its own argument.
+            while IFS= read -r -d '' _c; do _args+=("$_c"); done 2>/dev/null < "$_d/cmdline" || true
+            [ "${#_args[@]}" -gt 0 ] || continue
+            _name=${_args[0]}
+            if [ "${#_args[@]}" -gt 1 ]; then
+              case ${_name##*/} in FEX|FEXInterpreter) _name=${_args[1]} ;; esac
+            fi
+            case ${_name##*/} in
+              reaper)
+                for _a in "${_args[@]}"; do
+                  case $_a in
+                    AppId=769) ;;
+                    AppId=[0-9]*)
+                      _id=${_a#AppId=}
+                      case $_id in *[!0-9]*) ;; *) _bl_game=1; _bl_apps="$_bl_apps $_id" ;; esac
+                      ;;
+                  esac
+                done
+                ;;
+              steam|steamwebhelper) _bl_pids+=("${_d##*/}") ;;
+              *) _bl_others+=("${_d##*/}") ;;
             esac
           done
         }
@@ -534,6 +550,22 @@ case $mode in
           bl_zram_pick "$_which"
           step "zRAM: done ($(bl_zram_usage "${_pids[@]}"))"
         }
+        # Proton starts its reaper before the game window; compressing during launch stalls it.
+        # Desktop Steam has no focus.json, so it still uses the game process as its trigger.
+        # A configured RAM cap can still force compression while a game is launching.
+        bl_game_focused() {
+          if [ "${BL_DESKTOP:-}" = 1 ] || [ -z "${BL_LAUNCH_DIR:-}" ]; then
+            return 0
+          fi
+          local id
+          id=$(sed -n 's/.*"focusedApp"[[:space:]]*:[[:space:]]*\([0-9][0-9]*\).*/\1/p' \
+            "$BL_LAUNCH_DIR/agent/focus.json" 2>/dev/null | head -1)
+          [ -n "$id" ] || return 1
+          case " ${_bl_apps-} " in
+            *" $id "*) return 0 ;;
+          esac
+          return 1
+        }
         bl_over_cap() {
           [ "$_bl_ram_cap" -gt 0 ] || return 1
           _bl_measured=$SECONDS
@@ -544,7 +576,7 @@ case $mode in
         bl_cap_due() {
           [ "$_bl_ram_cap" -gt 0 ] && { [ "$_bl_measured" -lt 0 ] || [ $((SECONDS - _bl_measured)) -ge 30 ]; }
         }
-        _bl_since=-1 _bl_packed=-1 _bl_measured=-1 _bl_unpack=0 _bl_capped=-1 _bl_backoff=30
+        _bl_since=-1 _bl_since_apps= _bl_packed=-1 _bl_measured=-1 _bl_unpack=0 _bl_capped=-1 _bl_backoff=30
         while kill -0 $$ 2>/dev/null; do
           bl_zram_scan
           if bl_cap_due; then
@@ -575,18 +607,22 @@ case $mode in
               fi
             fi
           fi
-          if [ "$_bl_game" = 1 ]; then
-            [ "$_bl_since" -ge 0 ] || _bl_since=$SECONDS
+          if [ "$_bl_game" = 1 ] && bl_game_focused; then
+            if [ "$_bl_since" -lt 0 ] || [ "$_bl_since_apps" != "$_bl_apps" ]; then
+              _bl_since=$SECONDS _bl_since_apps=$_bl_apps
+            fi
             if [ "${BL_ZRAM_CLIENT:-1}" = 1 ] && [ $((SECONDS - _bl_since)) -ge 20 ] && [ "${#_bl_pids[@]}" -gt 0 ] &&
                { [ "$_bl_packed" -lt 0 ] || [ $((SECONDS - _bl_packed)) -ge 300 ]; }; then
               bl_zram_send 1 "compressing the client" client
               _bl_packed=$SECONDS
             fi
-          elif [ "$_bl_since" -ge 0 ]; then
+          elif [ "$_bl_game" != 1 ]; then
             if [ "$_bl_packed" -ge 0 ]; then
               if bl_over_cap; then _bl_unpack=1; else bl_zram_send 0 "game closed, reading the client back" client; _bl_unpack=0; fi
             fi
             _bl_since=-1 _bl_packed=-1
+          else
+            _bl_since=-1
           fi
           nap 5
         done

tools/tests/test_client_zram_focus.py

@@ -0,0 +1,169 @@
+from pathlib import Path
+import subprocess
+import tempfile
+import unittest
+
+
+SCRIPT = Path(__file__).resolve().parents[1] / 'linuxfs/overlay/usr/local/bin/droiddeck-session'
+
+
+def function_source(name):
+    source = SCRIPT.read_text()
+    start = source.index('%s() {' % name)
+    end = source.index('\n        }', start)
+    return source[start:end + len('\n        }')]
+
+
+def run_bash(script, env=None):
+    return subprocess.run(['bash', '-c', script], capture_output=True, text=True, timeout=10, env=env)
+
+
+class ClientZramFocusTest(unittest.TestCase):
+    def test_refocus_restarts_the_delay_and_game_exit_restores_a_packed_client(self):
+        source = SCRIPT.read_text()
+        start = source.index('          if [ "$_bl_game" = 1 ] && bl_game_focused; then')
+        stop = source.index('          nap 5', start)
+        body = source[start:stop]
+        harness = '''
+_bl_since=-1 _bl_since_apps= _bl_packed=-1 _bl_apps=" 413150"
+_bl_pids=(123)
+bl_game_focused() { [ "$focused" = 1 ]; }
+bl_over_cap() { return 1; }
+bl_zram_send() { echo "send:$1"; }
+tick() {
+  SECONDS=$1 _bl_game=$2 focused=$3
+''' + body + '''
+}
+tick 0 1 1
+tick 5 1 0
+tick 30 1 1
+echo "refocus:$_bl_packed"
+tick 49 1 1
+tick 50 1 1
+tick 55 1 0
+tick 60 0 0
+'''
+        result = run_bash(harness)
+        self.assertEqual(0, result.returncode, result.stderr)
+        self.assertEqual('', result.stderr)
+        self.assertEqual(['refocus:-1', 'send:1', 'send:0'], result.stdout.splitlines())
+
+    def monitor_harness(self):
+        source = SCRIPT.read_text()
+        start = source.index('          bl_zram_scan\n          if bl_cap_due; then')
+        stop = source.index('          nap 5', start)
+        return '''
+_bl_since=-1 _bl_since_apps= _bl_packed=-1 _bl_measured=-1 _bl_unpack=0 _bl_capped=-1 _bl_backoff=30
+_bl_apps=" 413150"
+_bl_pids=(123)
+step() { :; }
+bl_zram_scan() { :; }
+bl_game_focused() { [ "$focused" = 1 ]; }
+bl_cap_due() { [ "$cap_due" = 1 ]; }
+bl_over_cap() { [ "$over_cap" = 1 ]; }
+bl_zram_send() { echo "send:$1:$3"; }
+tick() {
+  SECONDS=$1 _bl_game=$2 focused=$3 over_cap=$4 cap_due=$5
+''' + source[start:stop] + '\n}\n'
+
+    def test_client_toggle_still_disables_automatic_compression(self):
+        result = run_bash(self.monitor_harness() + '''
+BL_ZRAM_CLIENT=0
+tick 0 1 1 0 0
+tick 25 1 1 0 0
+tick 30 0 0 0 0
+''')
+        self.assertEqual(0, result.returncode, result.stderr)
+        self.assertEqual('', result.stderr)
+        self.assertEqual('', result.stdout)
+
+    def test_a_new_game_restarts_the_compression_delay(self):
+        result = run_bash(self.monitor_harness() + '''
+tick 0 1 1 0 0
+_bl_apps=" 413150 1245620"
+tick 15 1 1 0 0
+tick 20 1 1 0 0
+echo "starting:$_bl_packed"
+tick 34 1 1 0 0
+tick 35 1 1 0 0
+''')
+        self.assertEqual(0, result.returncode, result.stderr)
+        self.assertEqual('', result.stderr)
+        self.assertEqual(['starting:-1', 'send:1:client'], result.stdout.splitlines())
+
+    def test_ram_cap_can_still_compress_an_unfocused_client(self):
+        result = run_bash(self.monitor_harness() + '''
+BL_ZRAM_CLIENT=0 BL_RAM_CAP_MB=1024
+bl_zram_usage() { _bl_rss=$((768 * 1024)); }
+tick 0 1 0 1 1
+echo "cap:$_bl_packed:$_bl_since:$_bl_backoff"
+tick 5 0 0 0 0
+''')
+        self.assertEqual(0, result.returncode, result.stderr)
+        self.assertEqual('', result.stderr)
+        self.assertEqual(['send:1:client', 'send:1:session', 'cap:0:-1:60', 'send:0:client'], result.stdout.splitlines())
+
+    def test_game_exit_defers_restore_until_the_session_is_under_the_ram_cap(self):
+        result = run_bash(self.monitor_harness() + '''
+tick 0 1 1 0 0
+tick 20 1 1 0 0
+tick 25 1 0 0 0
+tick 30 0 0 1 0
+echo "deferred:$_bl_unpack:$_bl_packed"
+tick 35 0 0 0 1
+echo "restored:$_bl_unpack"
+''')
+        self.assertEqual(0, result.returncode, result.stderr)
+        self.assertEqual('', result.stderr)
+        self.assertEqual(['send:1:client', 'deferred:1:-1', 'send:0:client', 'restored:0'], result.stdout.splitlines())
+
+    def test_scan_keeps_the_running_game_and_ignores_steams_own_reaper(self):
+        temp = tempfile.TemporaryDirectory()
+        self.addCleanup(temp.cleanup)
+        root = Path(temp.name)
+        self.write_cmd(root, 10, ['/usr/lib/steam/reaper', 'SteamLaunch', 'AppId=769', '--'])
+        self.write_cmd(root, 20, ['/usr/bin/FEX', '/usr/lib/steam/reaper', 'SteamLaunch', 'AppId=1245620', '--'])
+        self.write_cmd(root, 30, ['/home/deck/.local/share/Steam/steamrtarm64/steam'])
+        self.write_cmd(root, 40, ['/usr/bin/wine', 'game.exe'])
+        self.write_cmd(root, 50, ['/usr/bin/FEXInterpreter', '/usr/bin/steamwebhelper'])
+        scan = function_source('bl_zram_scan').replace('for _d in /proc/[0-9]*', 'for _d in "$FAKE"/[0-9]*')
+        result = run_bash('FAKE=%s\n%s\nbl_zram_scan\necho "game=$_bl_game"\necho "apps=${_bl_apps# }"\necho "pids=${_bl_pids[*]}"\necho "others=${_bl_others[*]}"' % (root, scan))
+        self.assertEqual(0, result.returncode, result.stderr)
+        self.assertEqual(['game=1', 'apps=1245620', 'pids=30 50', 'others=40'], result.stdout.splitlines())
+
+    def test_focus_must_be_the_running_game(self):
+        focus = function_source('bl_game_focused')
+        script = '''
+%s
+check() {
+  BL_DESKTOP=$1 BL_LAUNCH_DIR=$2 _bl_apps=$3
+  if bl_game_focused; then echo yes; else echo no; fi
+}
+check "" "$dir" " 413150"
+check "" "$dir" " 1245620"
+printf '%%s\\n' '{"focusedApp": 999}' > "$dir/agent/focus.json"
+check "" "$dir" " 413150"
+printf '%%s\\n' '{"focusedApp": 769}' > "$dir/agent/focus.json"
+check "" "$dir" " 413150"
+rm -f "$dir/agent/focus.json"
+check 1 "$dir" " 413150"
+check "" "" " 413150"
+''' % focus
+        temp = tempfile.TemporaryDirectory()
+        self.addCleanup(temp.cleanup)
+        launch = Path(temp.name)
+        (launch / 'agent').mkdir()
+        (launch / 'agent' / 'focus.json').write_text('{"t": 1, "focusedApp": 413150}\n')
+        result = run_bash('dir=%s\n%s' % (launch, script))
+        self.assertEqual(0, result.returncode, result.stderr)
+        self.assertEqual(['yes', 'no', 'no', 'no', 'yes', 'yes'], result.stdout.splitlines())
+
+    @staticmethod
+    def write_cmd(root, pid, args):
+        proc = root / str(pid)
+        proc.mkdir()
+        (proc / 'cmdline').write_bytes(b'\0'.join(arg.encode() for arg in args) + b'\0')
+
+
+if __name__ == '__main__':
+    unittest.main()