[Vm-dev] Unix heartbeat thread vs itimer

[tim Rowledge]

> On 28-03-2017, at 9:46 AM, Holger Freyther <holger at freyther.de> wrote:
> 
> 
> 
>> On 28 Mar 2017, at 17:05, Ben Coman <btc at openinworld.com> wrote:
>> 
>> 
>> 
>> Just curious, what is the root cause of this itimer conflict?
>> Is it that a SIGALARM in particular is issued, or just that the
>> current execution is pre-empted to handle the signal - and is that a
>> timing issue, or a concurrency problem where some state is
>> invalidated?
>> 
>> Would it help if to handle the signal in another thread?
>> 
> 
> AFAICT the main issue is that it can not be shared/multiplexed. E.g. if both ALSA and the VM install an event handler for the signal it is not clear who will win. And they will probably cancel each others work.

Pretty much this; by advanced programming magic it manages to always work out to do *exactly* the worst thing.

tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Strange OpCodes: MT: Muddle Through