[elrepo] Realtime kernel for audio/games?

[Ljubomir Ljubojevic]

On 10/13/2014 03:51 PM, Alan Bartlett wrote:
> On 13 October 2014 12:38, Ljubomir Ljubojevic <centos at plnet.rs> wrote:
>> On 10/13/2014 01:23 PM, Ljubomir Ljubojevic wrote:
>>> On 10/13/2014 01:19 PM, Ljubomir Ljubojevic wrote:
>>>> Hi guys.
>>>>
>>>> Is there any desire, or even need to create a realtime kernel aimed at
>>>> audio/games?
>>>>
>>>> Since Desktop/gaming system and servers have different priorities, I was
>>>> wondering how things are with current CentOS kernels. For CentOS 5 there
>>>> were CCRMA kernels.
>>>>
>>>> Non-Gaming purpose would be for audio conversion/streaming.
>>>>
>>>
>>> Understanding low latency
>>>
>>> Summary
>>>
>>> Summarizing, you need tuned drivers that do not disable interrupts for
>>> long, low latency patches in the kernel so that the scheduler runs often
>>> enough and your application itself has to run with the SCHED_FIFO
>>> scheduling policy so that it gets the best chance of grabbing the
>>> processor when it needs it.
>>>
>>> When everything is in place things work incredibly well. The system can
>>> be running an audio task with no dropouts and a few milliseconds of
>>> latency while the computer is being loaded with disk accesses, screen
>>> refreshes and whatnot. The mouse gets jerky, windows update very slowly
>>> but not a dropout to be heard.
>>>
>>> I wonder if anybody got this far :-)
>>> http://ccrma.stanford.edu/planetccrma/software/understandlowlat.html
>>>
>>
>> I apologize for not doing some research later, I went back to CCRMA and
>> found out that there is repositories for Fedora 19, so patching
>> your/stock kernels should be fairly straightforward.
>>
>> http://ccrma.stanford.edu/planetccrma/software/installplanettwenty.html
>>
>> http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetccrma/19/SRPMS/
>>
>> I will contact the maintainer if he would create a branch for CentOS 7
>> and report back.
>>
>> --
>> Ljubomir Ljubojevic
> 
> Thank you. That would be the most sensible path to follow.
> 
> We would always encourage end-users with a need that is not satisfied
> by the basic kernel packages that we ship to investigate a "local"
> solution. Currently the build & provide of a kernel-lt package set for
> EL5, a kernel-lt & kernel-ml package set for EL6 and a kernel-ml
> package set for EL7 takes a significant amount of time. The logic
> behind our provision of the above is quite simple -- to allow end
> users to be able to make use of hardware which is currently
> unsupported by the distribution kernels and is also unsupported by
> means of a specific kmod package.
> 
> Specialised builds of a kernel (say, for example, Xen or RT) are
> something that we will not be providing. However we will always try to
> assist an end user to understand our current build process and thus to
> be able to become "self-sufficient" in maintaining a "local" build of
> such specialist kernels.
> 
> Alan.


As far as I read their mailing list, maintainers do not use CentOS 7. I
will see what they think of my request and will see what to do next.
Maybe something like CentOS Variant/SiG can be formed.


-- 
Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

StarOS, Mikrotik and CentOS/RHEL/Linux consultant