As Qt switched from v8 to v4 (replacing the code that triggered this) and we haven't seen this in a long time, we can close this now.
** Changed in: unity8 (Ubuntu) Status: Confirmed => Incomplete ** Changed in: unity8 (Ubuntu) Status: Incomplete => Invalid -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to unity8 in Ubuntu. https://bugs.launchpad.net/bugs/1219871 Title: when idle with screen blank, unity8 generates hundreds of context switches per second Status in “unity8” package in Ubuntu: Invalid Bug description: To reproduce (on maguro, Samsung Galaxy Nexus): sudo apt-get install sysstat ensure idle has occurred and screen is now blank, ssh in and run pidstat -w 10 1 Linux 3.0.0-3-maguro (ubuntu-phablet) 09/02/2013 _armv7l_ (2 CPU) 03:04:13 PM UID PID cswch/s nvcswch/s Command 03:04:23 PM 0 3 1.19 0.00 ksoftirqd/0 03:04:23 PM 0 9 1.29 0.00 ksoftirqd/1 03:04:23 PM 0 13 0.20 0.00 sync_supers 03:04:23 PM 0 20 21.99 0.00 kworker/0:1 03:04:23 PM 0 23 0.40 0.00 kinteractiveup 03:04:23 PM 0 69 1.29 0.00 kworker/1:1 03:04:23 PM 0 88 2.09 0.00 mmcqd/0 03:04:23 PM 0 96 0.30 0.00 dhd_watchdog 03:04:23 PM 0 97 8.46 0.00 dhd_dpc 03:04:23 PM 0 156 0.90 0.00 jbd2/mmcblk0p12 03:04:23 PM 103 418 0.50 0.00 dbus-daemon 03:04:23 PM 0 429 0.20 0.00 flush-179:0 03:04:23 PM 1000 493 70.05 0.00 surfaceflinger 03:04:23 PM 32011 613 0.20 0.00 init 03:04:23 PM 32011 658 0.10 0.00 dbus-daemon 03:04:23 PM 32011 713 467.86 0.10 unity8 03:04:23 PM 32011 788 0.10 0.00 upstart-dbus-br 03:04:23 PM 32011 790 0.10 0.00 upstart-dbus-br 03:04:23 PM 0 862 3.98 2.79 NetworkManager 03:04:23 PM 0 1179 0.10 0.00 wpa_supplicant 03:04:23 PM 32011 1219 0.10 0.40 indicator-netwo 03:04:23 PM 0 1237 0.20 0.00 ofonod 03:04:23 PM 32011 1335 0.10 0.00 mission-control 03:04:23 PM 32011 1339 0.40 0.00 telepathy-ofono 03:04:23 PM 0 1929 222.59 1.09 kworker/u:0 03:04:23 PM 0 2379 222.89 0.00 kworker/u:1 03:04:23 PM 32011 2944 0.10 2.19 pidstat unity8 with PID 713 is performing ~450-470 context switches a second. But what is it doing? sudo add-apt-repository ppa:colin-king/white && sudo apt-get update && sudo apt-get install health-check sudo health-check -p 713 -d 10 CPU usage: PID Process USR% SYS% TOTAL% 713 unity8 27.29 6.40 33.69 (medium load) ^^ that's kinda busy! Wakeups: No wakeups detected File I/O operations: No file I/O operations detected System calls traced: PID Process Syscall Count Rate/Sec 713 unity8 futex 3904 390.2976 713 unity8 clock_gettime 1384 138.3637 713 unity8 poll 791 79.0792 713 unity8 read 789 78.8793 713 unity8 recvmsg 4 0.3999 713 unity8 write 4 0.3999 713 unity8 restart_syscall 1 0.1000 Total 6877 687.5196 Looks like it may be context switching like mad on a futex. When the screen is not blank but device is idle, unity8 is far less busy. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity8/+bug/1219871/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp