OK, a bit more data:
Xenial with 4.4 and 4.8 kernels - works fine (so not a 4.8 kernel regression)
Yakkety with 4.4 and 4.8 kernels - shows the slow behavior (so not a kernel
issue)
So I think this is a problem in the plumbing layer.
** Changed in: systemd (Ubuntu)
Assignee: (unassigned) => Martin Pitt (pitti)
** Tags removed: kernel-4.8
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https://bugs.launchpad.net/bugs/1626651
Title:
brightness keys are handled slower in Yakkety than Xenial
Status in linux package in Ubuntu:
Incomplete
Status in systemd package in Ubuntu:
New
Bug description:
I've noticed on Lenovo X220 and X230 laptops that pressing brightness
keys on Yakkety seems less responsive and slower than Xenial. I ran
forkstat on Xenial and just observed udev being forked off:
Xenial:
$ sudo forkstat
Time Event PID Info Duration Process
17:37:35 fork 273 parent /lib/systemd/systemd-udevd
17:37:35 fork 1977 child /lib/systemd/systemd-udevd
17:37:35 exit 1977 0 0.008 /lib/systemd/systemd-udevd
Whereas on Yakkety, there is far more activity:
Time Event PID Info Duration Process
16:35:34 fork 2626 parent update-notifier
16:35:34 fork 2645 child update-notifier
16:35:34 exec 2645 /usr/bin/python3
/usr/share/apport/apport-checkreports
16:35:34 exit 2645 256 0.221 /usr/bin/python3
/usr/share/apport/apport-checkreports
16:35:34 fork 2626 parent update-notifier
16:35:34 fork 2646 child update-notifier
16:35:34 exec 2646 /usr/bin/python3
/usr/share/apport/apport-checkreports --system
16:35:34 exit 2646 256 0.188 /usr/bin/python3
/usr/share/apport/apport-checkreports --system
16:35:36 fork 1576 parent
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 fork 2647 child
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 exec 2647
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness
16:35:36 exit 2647 0 0.008
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness
16:35:36 fork 1576 parent
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 fork 2648 child
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 exec 2648
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness
16:35:36 exit 2648 0 0.006
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness
16:35:36 fork 1576 parent
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 fork 2649 child
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 exec 2649
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness
16:35:36 exit 2649 0 0.007
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-brightness
16:35:36 fork 1576 parent
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 fork 2650 child
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 exec 2650
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness
16:35:36 exit 2650 0 0.006
/usr/lib/unity-settings-daemon/usd-backlight-helper --get-max-brightness
16:35:36 fork 1576 parent
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 fork 2651 child
/usr/lib/unity-settings-daemon/unity-settings-daemon
16:35:36 exec 2651 pkexec
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 clone 2651 parent pkexec
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 clone 2652 thread pkexec
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 clone 2651 parent pkexec
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 clone 2653 thread pkexec
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 fork 1 parent /sbin/init splash
16:35:36 fork 2654 child /sbin/init splash
Time Event PID Info Duration Process
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2655 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2656 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2657 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2658 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2659 child /lib/systemd/systemd-udevd
16:35:36 exit 2659 0 0.005 /lib/systemd/systemd-udevd
16:35:36 exit 2658 0 0.006 /lib/systemd/systemd-udevd
16:35:36 exit 2657 0 0.007 /lib/systemd/systemd-udevd
16:35:36 exit 2656 0 0.008 /lib/systemd/systemd-udevd
16:35:36 exit 2655 0 0.008 /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2660 child /lib/systemd/systemd-udevd
16:35:36 exit 2660 0 0.001 /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2661 child /lib/systemd/systemd-udevd
16:35:36 exit 2661 0 0.002 /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2662 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2663 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2664 child /lib/systemd/systemd-udevd
16:35:36 fork 2654 parent /sbin/init splash
16:35:36 fork 2665 child (systemd)
16:35:36 exec 2654 /lib/systemd/systemd --user
16:35:36 exit 2662 0 0.010 /lib/systemd/systemd-udevd
16:35:36 exit 2664 0 0.007 /lib/systemd/systemd-udevd
Time Event PID Info Duration Process
16:35:36 exit 2663 0 0.009 /lib/systemd/systemd-udevd
16:35:36 fork 2654 parent /lib/systemd/systemd --user
16:35:36 fork 2666 child /lib/systemd/systemd --user
16:35:36 exit 2666 0 0.001 /lib/systemd/systemd --user
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2667 child /lib/systemd/systemd-udevd
16:35:36 exit 2667 0 0.003 /lib/systemd/systemd-udevd
16:35:36 fork 2654 parent /lib/systemd/systemd --user
16:35:36 fork 2668 child /lib/systemd/systemd --user
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2669 child /lib/systemd/systemd-udevd
16:35:36 exit 2669 0 0.002 /lib/systemd/systemd-udevd
16:35:36 exec 2668 /bin/systemctl --user set-environment
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/0/bus
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2670 child /lib/systemd/systemd-udevd
16:35:36 exit 2670 0 0.001 /lib/systemd/systemd-udevd
16:35:36 exit 2668 0 0.009 /bin/systemctl --user set-environment
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/0/bus
16:35:36 fork 2 parent [kthreadd]
16:35:36 fork 2671 child [kworker/u16:4]
16:35:36 exec 2671 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service/dbus.socket]
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2672 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2673 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2674 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2675 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2676 child /lib/systemd/systemd-udevd
16:35:36 exit 2671 0 0.005 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service/dbus.socket]
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
Time Event PID Info Duration Process
16:35:36 fork 2677 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2678 child /lib/systemd/systemd-udevd
16:35:36 exit 2653 0 0.126 pkexec
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 exit 2652 0 0.126 pkexec
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 exec 2651
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 exit 2673 0 0.013 /lib/systemd/systemd-udevd
16:35:36 exit 2672 0 0.013 /lib/systemd/systemd-udevd
16:35:36 exit 2678 0 0.011 /lib/systemd/systemd-udevd
16:35:36 exit 2675 0 0.013 /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2679 child /lib/systemd/systemd-udevd
16:35:36 exit 2674 0 0.020 /lib/systemd/systemd-udevd
16:35:36 exit 2651 0 0.146
/usr/lib/unity-settings-daemon/usd-backlight-helper --set-brightness 2250
16:35:36 fork 2 parent [kthreadd]
16:35:36 fork 2680 child [kworker/u16:5]
16:35:36 exec 2680 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/session-2.scope]
16:35:36 exit 2676 0 0.022 /lib/systemd/systemd-udevd
16:35:36 exit 2679 0 0.003 /lib/systemd/systemd-udevd
16:35:36 exit 2677 0 0.022 /lib/systemd/systemd-udevd
16:35:36 exit 2680 0 0.003 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/session-2.scope]
16:35:36 fork 2654 parent /lib/systemd/systemd --user
16:35:36 fork 2681 child /lib/systemd/systemd --user
16:35:36 exec 2681 /bin/kill -s 58 2654
16:35:36 exit 2681 0 0.200 /bin/kill -s 58 2654
16:35:36 fork 2 parent [kthreadd]
16:35:36 fork 2682 child [kworker/u16:5]
16:35:36 exec 2682 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service/systemd-exit.service]
16:35:36 exit 2654 0 0.294 /lib/systemd/systemd --user
16:35:36 exit 2682 0 0.004 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service/systemd-exit.service]
16:35:36 exit 2665 9 0.272 (systemd)
16:35:36 fork 2 parent [kthreadd]
Time Event PID Info Duration Process
16:35:36 fork 2683 child [kworker/u16:5]
16:35:36 exec 2683 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service/init.scope]
16:35:36 fork 2 parent [kthreadd]
16:35:36 fork 2684 child [kworker/u16:4]
16:35:36 fork 2 parent [kthreadd]
16:35:36 fork 2685 child [systemd-cgroups]
16:35:36 exec 2684 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service]
16:35:36 exec 2685 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice]
16:35:36 exit 2683 0 0.005 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service/init.scope]
16:35:36 exit 2685 0 0.005 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice]
16:35:36 exit 2684 0 0.007 [/lib/systemd/systemd-cgroups-agent
/user.slice/user-0.slice/user@0.service]
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2686 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2687 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2688 child /lib/systemd/systemd-udevd
16:35:36 fork 233 parent /lib/systemd/systemd-udevd
16:35:36 fork 2689 child /lib/systemd/systemd-udevd
16:35:36 exit 2687 0 0.014 /lib/systemd/systemd-udevd
16:35:36 exit 2689 0 0.013 /lib/systemd/systemd-udevd
16:35:36 exit 2686 0 0.015 /lib/systemd/systemd-udevd
16:35:36 exit 2688 0 0.015 /lib/systemd/systemd-udevd
I suspect some of this overhead explains the slower responsive feel to
the brightness buttons. Anyhow, seems like a bit of an overkill for
all these processes to be running especially compared to Xenial.
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