Some problems with the libbsd update

[Chris Johns]

On 23/08/2018 15:09, Sebastian Huber wrote:
> On 23/08/18 01:00, Chris Johns wrote:
>> On 22/08/2018 22:25, Sebastian Huber wrote:
>>> On 22/08/18 14:06, Joel Sherrill wrote:
>>>> On Wed, Aug 22, 2018, 6:47 AM Sebastian Huber
>>>> <sebastian.huber at embedded-brains.de
>>>> <mailto:sebastian.huber at embedded-brains.de>> wrote:
>>>>
>>>> It really is necessary to know how the other architectures implement it. Some
>>>> may turn out to be easy. Others like Epiphany and new may never matter.
>>> If the niche architectures don't use libbsd (which I guess is the case), then
>>> there is no issue at all.
>>>
>> Do we document what is supported and what is not supported?
> 
> The status of the SMP and TLS support is documented in the CPU Supplement.
> 
> We added the TLS support for ARM, m68k, PowerPC and SPARC in January 2014 and
> also recently for RISC-V. TLS is a C11 standard element. All RTEMS architectures
> which don't support it have a maintainer problem from my point of view.
> 

Thanks

>>
>> Does libbsd have suitable checks on the built RTEMS to know it cannot be
>> supported?
> 
> One way to figure out if it basically works is to run the tests.
> 

I am referring to a configure type test. See the opts types tests rtems_waf
already supports, for example SMP.

>>
>> FWIW I do not think the idea of "one size fits all" is workable. I think a
>> number of architectures would benefit from a different smaller networking stack.
> 
> libbsd is not only a network stack. It contains also USB and MMC card support. I
> work on a port of the NVMe support currently.
> 
> FreeBSD seems to receive a huge funding from CDN providers such as Netfix and
> Limelight Networks. They probably don't care about uni-processor system support
> at all. The use of lock-free data structures (Concurrency Kit) and the epoch
> memory reclamation are now a mandatory infrastructure. There is no FreeBSD
> configuration option to avoid this. This was a bit surprising to me. It was also
> introduced less than half a year before the planned FreeBSD 12 release.
> 
> The recent changes in FreeBSD make the lwIP network stack even more attractive
> for low-end targets.

Yes.

Chris