Comment 5 for bug 1488426

lpuser (lpuser) wrote :

I'm also affected by this issue and it's very annoying as it sucks all my battery!
I have a Dell Inspiron 5555 powered by an AMD A8-7410 and 4G of RAM (which is BTW certified for Ubuntu 14.04).

Here's the top output:

$ top -b -n1
top - 11:20:15 up 42 min, 2 users, load average: 1,77, 1,72, 1,62
Tasks: 217 total, 2 running, 215 sleeping, 0 stopped, 0 zombie
%Cpu(s): 3,9 us, 22,2 sy, 0,0 ni, 70,5 id, 1,5 wa, 0,0 hi, 1,9 si, 0,0 st
KiB Mem: 3400808 total, 1822148 used, 1578660 free, 64956 buffers
KiB Swap: 7812092 total, 0 used, 7812092 free. 764228 cached Mem

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
   75 root 20 0 0 0 0 R 56,7 0,0 22:56.39 kworker/3:2
   29 root 20 0 0 0 0 S 37,8 0,0 16:05.42 ksoftirqd/3

And this is the perf report:

+ 65,62% 0,00% kworker/3:2 [kernel.kallsyms] [k] ret_from_fork ▒
+ 65,62% 0,00% kworker/3:2 [kernel.kallsyms] [k] kthread ▒
+ 65,51% 0,11% kworker/3:2 [kernel.kallsyms] [k] worker_thread ▒
+ 65,26% 0,67% kworker/3:2 [kernel.kallsyms] [k] process_one_work ▒
+ 61,64% 0,78% kworker/3:2 [kernel.kallsyms] [k] rpm_idle ▒
+ 60,01% 0,32% kworker/3:2 [kernel.kallsyms] [k] pm_runtime_work ▒
+ 59,27% 0,99% kworker/3:2 [kernel.kallsyms] [k] rpm_suspend ▒
+ 58,95% 0,14% kworker/3:2 [kernel.kallsyms] [k] __rpm_callback ▒
+ 58,76% 0,22% kworker/3:2 [kernel.kallsyms] [k] usb_runtime_idle ▒
+ 58,37% 0,24% kworker/3:2 [kernel.kallsyms] [k] __pm_runtime_suspend ▒
+ 56,79% 0,24% kworker/3:2 [kernel.kallsyms] [k] rpm_callback ▒
+ 56,41% 0,25% kworker/3:2 [kernel.kallsyms] [k] usb_runtime_suspend ▒
+ 56,11% 0,75% kworker/3:2 [kernel.kallsyms] [k] usb_suspend_both ▒
+ 42,00% 0,36% kworker/3:2 [kernel.kallsyms] [k] usb_resume_interface.isra.6 ▒
+ 41,69% 0,24% kworker/3:2 [kernel.kallsyms] [k] hub_resume ▒
+ 41,30% 0,81% kworker/3:2 [kernel.kallsyms] [k] hub_activate ▒
+ 37,38% 0,66% kworker/3:2 [kernel.kallsyms] [k] hub_port_status ▒
+ 36,29% 0,49% kworker/3:2 [kernel.kallsyms] [k] usb_control_msg ▒
+ 33,50% 0,50% kworker/3:2 [kernel.kallsyms] [k] usb_start_wait_urb ▒
+ 26,53% 0,43% kworker/3:2 [kernel.kallsyms] [k] usb_submit_urb ▒
+ 26,08% 2,32% kworker/3:2 [kernel.kallsyms] [k] usb_submit_urb.part.6 ▒
+ 22,69% 1,63% kworker/3:2 [kernel.kallsyms] [k] usb_hcd_submit_urb ▒
+ 19,59% 0,00% ksoftirqd/3 [kernel.kallsyms] [k] ret_from_fork ▒
+ 19,59% 0,00% ksoftirqd/3 [kernel.kallsyms] [k] kthread ▒
+ 18,21% 1,18% ksoftirqd/3 [kernel.kallsyms] [k] smpboot_thread_fn ▒
+ 15,07% 0,52% kworker/3:2 [kernel.kallsyms] [k] usb_hcd_giveback_urb ▒
+ 14,08% 0,21% kworker/3:2 [kernel.kallsyms] [k] wakeup_softirqd ▒
+ 13,67% 0,05% kworker/3:2 [kernel.kallsyms] [k] wake_up_process ▒
+ 13,04% 1,04% kworker/3:2 [kernel.kallsyms] [k] try_to_wake_up ▒
+ 12,52% 0,55% kworker/3:2 [kernel.kallsyms] [k] hub_suspend ▒
+ 11,88% 0,08% kworker/3:2 [kernel.kallsyms] [k] hub_quiesce ▒
+ 10,97% 0,38% kworker/3:2 [kernel.kallsyms] [k] ttwu_do_activate.constprop.94 ▒
+ 10,57% 0,19% kworker/3:2 [kernel.kallsyms] [k] usb_kill_urb ▒
+ 10,53% 0,75% kworker/3:2 [kernel.kallsyms] [k] _cond_resched ▒
+ 9,88% 9,65% kworker/3:2 [kernel.kallsyms] [k] xhci_hub_control ▒
+ 9,56% 2,06% kworker/3:2 [kernel.kallsyms] [k] __sched_text_start ▒
+ 9,41% 0,48% ksoftirqd/3 [kernel.kallsyms] [k] schedule ▒
+ 9,23% 0,46% kworker/3:2 [kernel.kallsyms] [k] __tasklet_schedule

Please note that I'm using Ubuntu 14.04.3 with the latest updates.

Kernel:
$ uname -a
Linux quasar 3.19.0-28-generic #30~14.04.1-Ubuntu SMP Tue Sep 1 09:32:55 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Also tested the kernel with the patches from:
http://people.canonical.com/~acelan/lp1475248/

But it doesn't fix the issue on my laptop.

Another important detail is that after a fresh restart those 2 processes don't eat up the CPU.
However, at some point there is something that triggers the issue.
For instance, one thing that it seems to trigger it is watching flash videos on youtube with chromium browser.
The only way to stop the issue is to reboot.

IMHO we should raise the severity of this bug.

I'm willing to help with debugging and testing.

Thanks!