/bin/wifi: setclient performance improvements.
Use wpa_cli reconfigure rather than stopping and starting
wpa_supplicant. This makes associating with a new AP much faster.
The total /bin/wifi time to reassociate is now ~3 seconds, down from
10-15. Most of this is /bin/wifi itself, but reassociating can still
take ~1s.
If an AP is running as well, it will still take time to stop and
restart that, but once b/30140131 is resolved we may be able to remove
that as well.
Change-Id: Id26f7ab9b3c82aba9c06f7889c33d13455d5b5eb
diff --git a/wifi/wifi.py b/wifi/wifi.py
index b0ef7f9..8797633 100755
--- a/wifi/wifi.py
+++ b/wifi/wifi.py
@@ -542,9 +542,20 @@
('hostapd_cli', '-i', interface, 'status'), no_stdout=True) == 0
-def _is_wpa_supplicant_running(interface):
+def _wpa_cli(program, interface, command):
return utils.subprocess_quiet(
- ('wpa_cli', '-i', interface, 'status'), no_stdout=True) == 0
+ (program, '-i', interface, command), no_stdout=True) == 0
+
+
+def _is_wpa_supplicant_running(interface):
+ return _wpa_cli('wpa_cli', interface, 'status')
+
+
+def _reconfigure_wpa_supplicant(interface):
+ if not _wpa_cli('wpa_cli', interface, 'reconfigure'):
+ return False
+
+ return _wait_for_wpa_supplicant_to_associate(interface)
def _hostapd_debug_options():
@@ -653,6 +664,38 @@
return None
+def _wait_for_wpa_supplicant_to_associate(interface):
+ """Wait for wpa_supplicant to associate.
+
+ If it does not associate within a certain period of time, terminate it.
+
+ Args:
+ interface: The interface on which wpa_supplicant is running.
+
+ Raises:
+ BinWifiException: if wpa_supplicant fails to associate and
+ also cannot be stopped to cleanup after the failure.
+
+ Returns:
+ Whether wpa_supplicant associated within the timeout.
+ """
+ utils.log('Waiting for wpa_supplicant to connect')
+ for _ in xrange(100):
+ if _get_wpa_state(interface) == 'COMPLETED':
+ utils.log('ok')
+ return True
+ sys.stderr.write('.')
+ time.sleep(0.1)
+
+ utils.log('wpa_supplicant did not connect.')
+ if not _stop_wpa_supplicant(interface):
+ raise utils.BinWifiException(
+ "Couldn't stop wpa_supplicant after it failed to connect. "
+ "Consider killing it manually.")
+
+ return False
+
+
def _start_wpa_supplicant(interface, config_filename):
"""Starts a babysat wpa_supplicant.
@@ -704,21 +747,7 @@
else:
return False
- utils.log('Waiting for wpa_supplicant to connect')
- for _ in xrange(100):
- if _get_wpa_state(interface) == 'COMPLETED':
- utils.log('ok')
- return True
- sys.stderr.write('.')
- time.sleep(0.1)
-
- utils.log('wpa_supplicant did not connect.')
- if not _stop_wpa_supplicant(interface):
- raise utils.BinWifiException(
- "Couldn't stop wpa_supplicant after it failed to connect. "
- "Consider killing it manually.")
-
- return False
+ return _wait_for_wpa_supplicant_to_associate(interface)
def _maybe_restart_hostapd(interface, config, opt):
@@ -777,8 +806,7 @@
def _restart_hostapd(band):
"""Restart hostapd from previous options.
- Only used by _maybe_restart_wpa_supplicant, to restart hostapd after stopping
- it.
+ Only used by _set_wpa_supplicant_config, to restart hostapd after stopping it.
Args:
band: The band on which to restart hostapd.
@@ -797,7 +825,7 @@
_run(argv)
-def _maybe_restart_wpa_supplicant(interface, config, opt):
+def _set_wpa_supplicant_config(interface, config, opt):
"""Starts or restarts wpa_supplicant unless doing so would be a no-op.
The no-op case (i.e. wpa_supplicant is already running with an equivalent
@@ -826,11 +854,12 @@
except IOError:
pass
- if not _is_wpa_supplicant_running(interface):
+ already_running = _is_wpa_supplicant_running(interface)
+ if not already_running:
utils.log('wpa_supplicant not running yet, starting.')
elif current_config != config:
# TODO(rofrankel): Consider using wpa_cli reconfigure here.
- utils.log('wpa_supplicant config changed, restarting.')
+ utils.log('wpa_supplicant config changed, reconfiguring.')
elif opt.force_restart:
utils.log('Forced restart requested.')
forced = True
@@ -838,12 +867,12 @@
utils.log('wpa_supplicant-%s already configured and running', interface)
return True
- if not _stop_wpa_supplicant(interface):
- raise utils.BinWifiException("Couldn't stop wpa_supplicant")
-
if not forced:
utils.atomic_write(tmp_config_filename, config)
+ # TODO(rofrankel): Consider removing all the restart hostapd stuff when
+ # b/30140131 is resolved. hostapd seems to keep working without being
+ # restarted, at least on Camaro.
restart_hostapd = False
ap_interface = iw.find_interface_from_band(band, iw.INTERFACE_TYPE.ap,
opt.interface_suffix)
@@ -852,13 +881,15 @@
opt_without_persist = options.OptDict({})
opt_without_persist.persist = False
opt_without_persist.band = opt.band
- # Code review: Will AP and client always have the same suffix?
opt_without_persist.interface_suffix = opt.interface_suffix
if not stop_ap_wifi(opt_without_persist):
raise utils.BinWifiException(
"Couldn't stop hostapd to start wpa_supplicant.")
- if not _start_wpa_supplicant(interface, tmp_config_filename):
+ if already_running:
+ if not _reconfigure_wpa_supplicant(interface):
+ raise utils.BinWifiException('Failed to reconfigure wpa_supplicant.')
+ elif not _start_wpa_supplicant(interface, tmp_config_filename):
raise utils.BinWifiException(
'wpa_supplicant failed to start. Look at wpa_supplicant logs for '
'details.')
@@ -934,7 +965,7 @@
('ip', 'link', 'set', interface, 'address', mac_address))
wpa_config = configs.generate_wpa_supplicant_config(opt.ssid, psk, opt)
- if not _maybe_restart_wpa_supplicant(interface, wpa_config, opt):
+ if not _set_wpa_supplicant_config(interface, wpa_config, opt):
return False
return True
