High CPU usage by Firefox after screensaver kicks in

[Kevin Oberman]

On Thu, Feb 19, 2015 at 8:46 PM, Mikhail T. <mi+thun at aldan.algebra.com>
wrote:

> Hello!
>
> I'm observing a strange situation on this newly rebuilt 10.1-STABLE/i386
> box. The running Firefox has a single window with two tabs open. It is
> perfectly idle and consuming no CPU.
>
> However, when the screensaver kicks in 3 minutes later, the CPU usage by
> firefox climbs all the way up -- way past the screen-saver and the Xorg
> process:
>
>       PID USERNAME    THR PRI NICE   SIZE    RES STATE    TIME    WCPU
>     COMMAND
>     75533 me           43  40    0   453M   356M uwait  186:01  82.57%
>     firefox
>     77018 me            1  54   10 54772K 33876K RUN      3:13   8.06%
>     carousel
>     13854 root          1  41    0 90756K 22392K select  10:22   1.95% Xorg
>
> As soon as I touch a mouse and the screen-saver disappears, firefox
> calms down and the computer is 100% idle again. It is as if firefox is
> programmed to do something CPU-intensive (protein-folding? SETI?) as
> soon as the computer's screen-saver turns on.
>
> Has anyone else seen this? What can be causing it? Thanks!
>
>     -mi
>

Just tried on my system running a recent 10-stable and firefox 35.0.1. No
significant change in firefox CPU use.
--
Kevin Oberman, Network Engineer, Retired
E-mail: rkoberman at gmail.com