[mythtv-users] MythBackend Suddenly swamping CPU on system

[Keith Pyle]

On 07/02/12 02:51, Niklas Brunlid wrote:
> On 1 July 2012 19:30, Robert M. Riches Jr.<rm.riches at jacob21819.net>  wrote:
>
>> >  On Sun, 01 Jul 2012 11:07:54 +0200, Jan Ceuleers wrote:
>>> >  >  Seems to be caused by the leap second insertion which happened overnight
>>> >  >  (UTC).
>> >
>> >  At least on my system (backend and frontend on same system), it
>> >  seemed connected to mysqld.  ...
>> >
> Exactly this happened to me, too. Though Firefox showed the same behavior
> as mysqld.
>
> Also, while I could start mythfrontend, it responded to one key event in
> total over 1-2 minutes but was otherwise frozen.
>
> A reboot solved the problem.
I've been following the issue on the Linux Kernel Mailing List 
(lkml.org).  The experience of those on this list is exactly consistent 
with the leap second bug.   The problem will be most apparent for 
programs that use timers for things like a futex wait.  mysqld and 
firefox are perfect examples.  The problem was likely introduced around 
kernel 2.6.22 and has been confirmed present all the way to 3.5.  For 
the gory details by one of the folks working on a patch, see 
https://lkml.org/lkml/2012/7/1/203.

The good news is that you don't have to worry about this problem again 
until the next leap second, in three years or so.  Presumably, there 
will be a patch somewhat sooner.  :-)

Keith