23 Jun
2011
23 Jun
'11
3:10 a.m.
Hi all,
since Ubuntu 10.10 the rt kernel it's not in the repos. Anyway it appears
you can still work in rt mode.
Does anybody know what happened and eventually what's the difference between
the rt kernel and the one provided in this distro?
I'm a bit confused about this.
Cheers
--
Giorgio Baù
*Sound engineer*
T.Rex Studio
www.trexstudio.com
23 Jun
23 Jun
3:13 a.m.
On Wed, Jun 22, 2011 at 9:10 PM, Giorgio - Audiophilo
<anomalsound(a)gmail.com> wrote:
since Ubuntu 10.10 the rt kernel it's not in the
repos. Anyway it appears
you can still work in rt mode.
Does anybody know what happened and eventually what's the difference between
the rt kernel and the one provided in this distro?
Are you sure you need an rt kernel? You can get realtime scheduling
for Jack with the stock kernel in Ubuntu and Ubuntu Studio.
http://www.jackaudio.org/realtime_vs_realtime_kernel
--
Brett W. McCoy -- http://www.electricminstrel.com
------------------------------------------------------------------------
"In the rhythm of music a secret is hidden; If I were to divulge it,
it would overturn the world."
-- Jelaleddin Rumi
3:19 a.m.
Are you sure you need an rt kernel? You can get
realtime scheduling
for Jack with the stock kernel in Ubuntu and Ubuntu Studio.
http://www.jackaudio.org/realtime_vs_realtime_kernel
Well, since the page says:
A kernel built with the realtime patches (an "RT kernel") is needed only if:
You want to run JACK with very low latency settings that require realtime
performance that can only be achieved with an RT kernel
I would say yes. I have a professional studio, so i need the best
performance in terms of latency.
I wonder why they put the rt kernel out of the repos.
--
Giorgio Baù
*Sound engineer*
T.Rex Studio
www.trexstudio.com
3:22 a.m.
On Thu, Jun 23, 2011 at 9:19 AM, Giorgio - Audiophilo
<anomalsound(a)gmail.com> wrote:
rt-patch only available for 2.6.33 and Ubuntu probably doesn't want a
kernel that old in their latest release. I think the rt-kernel was
always maintained by a separate pro-audio group in any case, probably
there were manpower problems.
Are you sure you need an rt kernel? You can get
realtime scheduling
for Jack with the stock kernel in Ubuntu and Ubuntu Studio.
http://www.jackaudio.org/realtime_vs_realtime_kernel
Well, since the page says:
A kernel built with the realtime patches (an "RT kernel") is needed only if:
You want to run JACK with very low latency settings that require realtime
performance that can only be achieved with an RT kernel
I would say yes. I have a professional studio, so i need the best
performance in terms of latency.
I wonder why they put the rt kernel out of the repos.
3:43 a.m.
Maybe this page could be of help:
https://wiki.ubuntu.com/RealTime
Anyway there's something i can't get:
Q: What is the difference between an -rt kernel and a -realtime kernel?
A: [...] The main difference is that the -rt kernel should be based on the
Ubuntu source tree [...] On the other hand, the -realtime kernel is a
PREEMPT_RT patched kernel based on the vanilla source tree (not the Ubuntu
source).This kernel will be missing Ubuntu specific code, patches or
security fixes and it isn't guaranteed to be compatible with any external
software (low level utilities, DKMS drivers and so on). It does not use the
same Linux kernel version as the -generic kernel, and so these two kernels
are not aligned
But at the top of this page it says:
The -preempt and -rt kernels are no longer being developed due to lack of
support. Focus has instead turned to the -lowlatency and -realtime kernels
Why do they focus on -realtime kernels which "ill be missing Ubuntu specific
code, patches or security fixes and it isn't guaranteed to be compatible
with any external software".
Maybe it's too late here 3:41 am and i'm a b
--
Giorgio Baù
*Sound engineer*
T.Rex Studio
www.trexstudio.com
3:43 a.m.
Maybe this page could be of help:
https://wiki.ubuntu.com/RealTime
Anyway there's something i can't get:
Q: What is the difference between an -rt kernel and a -realtime kernel?
A: [...] The main difference is that the -rt kernel should be based on the
Ubuntu source tree [...] On the other hand, the -realtime kernel is a
PREEMPT_RT patched kernel based on the vanilla source tree (not the Ubuntu
source).This kernel will be missing Ubuntu specific code, patches or
security fixes and it isn't guaranteed to be compatible with any external
software (low level utilities, DKMS drivers and so on). It does not use the
same Linux kernel version as the -generic kernel, and so these two kernels
are not aligned
But at the top of this page it says:
The -preempt and -rt kernels are no longer being developed due to lack of
support. Focus has instead turned to the -lowlatency and -realtime kernels
Why do they focus on -realtime kernels which "will be missing Ubuntu
specific code, patches or security fixes and it isn't guaranteed to be
compatible with any external software".
Maybe it's too late here 3:41 am and i'm a bit tired :)
--
Giorgio Baù
*Sound engineer*
T.Rex Studio
www.trexstudio.com
9:05 a.m.
On 06/23/2011 03:43 AM, Giorgio - Audiophilo wrote:
Why do they focus on -realtime kernels which
"will be missing Ubuntu
specific code, patches or security fixes and it isn't guaranteed to be
compatible with any external software".
Because packaging real-time kernel with the Ubuntu 'sauce' is more time
consuming and the Ubuntu Studio team is already short on devs.
Best,
Jeremy
9:27 p.m.
On Thu, Jun 23, 2011 at 09:05:05AM +0200, Jeremy Jongepier wrote:
On 06/23/2011 03:43 AM, Giorgio - Audiophilo wrote:
you mean merging -rt into 2.6.38 or something ?
thats not a task normal people should be dealing with.
and it certeinly isnt a job for non-fulltime kernel hackers.
Why do they focus on -realtime kernels which
"will be missing Ubuntu
specific code, patches or security fixes and it isn't guaranteed to be
compatible with any external software".
Because packaging real-time kernel with the Ubuntu 'sauce' is more
time consuming and the Ubuntu Studio team is already short on devs.
Best,
Jeremy
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--
torben Hohn
9:31 p.m.
On 06/23/2011 09:27 PM, torbenh wrote:
you mean merging -rt into 2.6.38 or something ?
thats not a task normal people should be dealing with.
and it certeinly isnt a job for non-fulltime kernel hackers.
Hello Torben,
No not merging but applying all the Ubuntu specific patches:
https://wiki.ubuntu.com/KernelTeam/UbuntuDelta/Karmic
Best,
Jeremy
24 Jun
24 Jun
2:46 a.m.
On Thu, Jun 23, 2011 at 09:31:50PM +0200, Jeremy Jongepier wrote:
On 06/23/2011 09:27 PM, torbenh wrote:
I've never been able to get anyone's "sauce" to combine with an Ingo -rt
patch cleanly.
I just usually grab the most recent available clean xsource for which an Ingo patch is
available, apply the appropriate Ingo patch, and then copy the Debian stock
/boot/config-blahblahblah settings to .config, then I just make oldconfig, taking careful
note to enable the RT scheduling and HPET when prompted. Then I just make-kpkg and off I
go, i.e.
CONCURRENCY_LEVEL=2 make-kpkg --initrd --rootcmd fakeroot --append-to-version=-foobarbaz
kernel_image kernel_headers
And, about 30% of the times the kernel will actually work. When it doesn't, it usually
requires turning off HPET or some such thing.
-ken
you mean merging -rt into 2.6.38 or something ?
thats not a task normal people should be dealing with.
and it certeinly isnt a job for non-fulltime kernel hackers.
Hello Torben,
No not merging but applying all the Ubuntu specific patches:
https://wiki.ubuntu.com/KernelTeam/UbuntuDelta/Karmic
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9 comments
7 participants
participants (7)
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Brett McCoy -
Giorgio - Audiophilo -
Jeremy Jongepier -
Jeremy Jongepier -
Ken Restivo -
Oon-Ee Ng -
torbenh