Time recorded in EVENT_LOG may be different from time in exp_main.
Exception occurs -> AEE collect data and write into exp_main takes some time.
SWT
How does SWT work?
Each 30 seconds, it will send event to important threads.
(ex. mainthread, android.ui, android.display, android.fg)
Go to sleep.
Time up (30s later), it will check whether it's able to get response from those threads.
If not, it will do predump.
NOTICE! It may not be exactly 30s, because if system is busy, then it may not be able to work.
SYS_ANDROID_LOG
11-17 01:46:04.468 947 1509 W Watchdog: SWT Watchdog before wait current time:549298598
11-17 01:46:04.468 947 1509 W Watchdog: SWT Watchdog before wait start:549298598
11-17 01:46:04.468 947 1509 W Watchdog: SWT Watchdog before wait CHECK_INTERVAL:30000
11-17 01:46:34.468 947 1509 W Watchdog: SWT Watchdog after wait current time:549328599
How does SWT work? (part2)
透過拿不拿的到 Lock 的方式來看系統是否卡住
會去每分鐘polling四個thread來看是否卡住
main thread
android.ui
android.display
android.fg
1 mins block --> timeout (30 seconds before will have predump)
Important logs
SYS_ANDROID_EVENT_LOG
11-17 01:47:12.088 947 1509 I watchdog: Blocked in handler on main thread (main)
SYS_ANDROID_LOG
# 30s block predump
11-17 01:46:04.468 947 1509 W Watchdog: SWT Watchdog before wait current time:549298598
11-17 01:46:04.468 947 1509 W Watchdog: SWT Watchdog before wait start:549298598
11-17 01:46:04.468 947 1509 W Watchdog: SWT Watchdog before wait CHECK_INTERVAL:30000
11-17 01:46:34.468 947 1509 W Watchdog: SWT Watchdog after wait current time:549328599
# signal by someone
11-17 01:46:42.087 947 1509 W Watchdog: SWT Watchdog before wait current time:549336217
11-17 01:46:42.087 947 1509 W Watchdog: SWT Watchdog before wait start:549336217
11-17 01:46:42.087 947 1509 W Watchdog: SWT Watchdog before wait CHECK_INTERVAL:30000
11-17 01:47:12.087 947 1509 W Watchdog: SWT Watchdog after wait current time:549366218
# 30s block again SWT occur
11-17 01:47:12.088 947 1509 E Watchdog: **SWT happen **Blocked in handler on main thread (main)
11-17 01:47:21.834 947 1509 I Watchdog_N: dumpKernelStacks
11-17 01:47:21.872 947 1509 V Watchdog: ** save all info before killnig system server **
11-17 01:47:21.897 947 1509 D AES : cause : system_server_watchdog
11-17 01:47:21.924 13965 13965 D AEE/AED : Type:system_server_watchdog
11-17 01:47:21.924 13965 13965 I AEE/AED : system_server_watchdog
main_log
11-17 01:47:12.088914 947 1509 D AEE/RTT_LIB: aee_exception_running: send req
11-17 01:47:12.089258 947 1509 D AEE/RTT_LIB: Rtt waiting daemon finish the job...
11-17 01:47:12.089799 26846 26846 D AEE/AED : $===AEE===AEE===AEE===$
11-17 01:47:12.089884 26846 26846 D AEE/AED : p 0 poll events 1 revents 1
11-17 01:47:12.090030 26846 26846 D AEE/AED : requesting from: pid=947 cmd=9
11-17 01:47:12.090098 26846 26846 D AEE/AED : Go RTT_AEE_GET_EXCEPTION_RUNNING
11-17 01:47:21.913622 13965 13965 I AEE/AED : FATAL 'SWT' raised
11-17 01:47:21.913700 13965 13965 I AEE/AED : Dumping EXP/SWT
