On 04/07/2018 09:57 AM, Philippe Gerum wrote:
> On 04/06/2018 06:51 PM, C Smith wrote:
>> Hi all--
>>
>> Our real time application has a main rt_task which runs concurrently with
>> several other rt_tasks (spawned using rt_task_create) and we are concerned
>> about a context switch in one of the tasks. The problematic task uses
>> libxml2 to parse an xml document sent over ethernet which seems to cause a
>> switch to secondary mode. Would this also switch the other tasks we are
>> running to secondary mode, or is it isolated?
> 
> This is isolated in the sense that only the xml parser task will switch
> to secondary mode.
> 
> However, this may still cause a priority inversion for any rt thread
> which synchronizes with that switching thread, since the former may end
> up waiting for a wake up event coming from the latter, which might be
> delayed until it switches back to rt mode.
> 

Also, unwanted mode switches might cause runtime overhead when they
happen frequently enough. So it depends on how frequently the parser
task is switching out of rt mode.

-- 
Philippe.

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