C11 Re: [PATCH 3/6] termios: Use C11 mutex for input/output
gedare at rtems.org
Tue Dec 20 21:20:10 UTC 2016
On Fri, Dec 16, 2016 at 11:26 AM, Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
> On 15/12/16 23:34, Chris Johns wrote:
>> On 15/12/2016 18:02, Sebastian Huber wrote:
>>> On 14/12/16 22:15, Chris Johns wrote:
>>>> On 15/12/2016 00:39, Sebastian Huber wrote:
>>>> Would the "tiny" footprint be smaller if all internal services
>>>> including compiler thread support are made C11? Could this actually be
>>>> done? Parts of POSIX has been creeping in over time so the position is
>>>> a little confused at the moment. I am not sure about a bits and pieces
>>>> approach, maybe a full switch is made.
>>> Yes, the footprint would be smaller. If we provide self-contained
>>> threads, then the footprint would be much smaller, e.g. no object
>>> administration, no heap.
>> Great. This is a powerful reason to look at moving in this direction and
>> removing the remaining POSIX usage in libstdthreads.
>> A brief audit of rtems.git shows the change is possible with less than 30
>> Classic task creates and a similar number of semaphore creates so a full
>> change look reachable which is nice.
>> Should we look at moving all internal services to C11 and standardise it?
>> I think there is value in doing this. It can be a post 4.12 branch activity.
> In contrast to the C11 mutexes, I don't see a real value in moving from
> Classic API tasks to C11 threads. The Classic API you have more control over
> task attributes, modes, priority, stack size, etc.
> I created two tickets:
> Joel, Gedare, what is your opinion with respect to C11 mutexes?
I haven't fully understood the distinction. I get that C11 are
individually (and collectively) smaller. I don't entirely get what is
their time-space tradeoff or when they are less desirable. I would
like to see a table that compares/contrasts these in a simple way to
evaluate. I will try to look closely at these different approaches in
a few weeks.
> Sebastian Huber, embedded brains GmbH
> Address : Dornierstr. 4, D-82178 Puchheim, Germany
> Phone : +49 89 189 47 41-16
> Fax : +49 89 189 47 41-09
> E-Mail : sebastian.huber at embedded-brains.de
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> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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