[PlanetCCRMA] kernel-rt latency issues

Tracey Hytry shakti at bayarea.net
Wed Oct 31 15:46:56 PDT 2012

It's my understanding that the ccrma kernel is a fedora kernel build with the real time patches applied.

And yes, you are correct about it being worse.  Before, when Fernanado would build them as a vanilla
kernel they were much better.  My understanding  is that the change was because it kept the kernel in line with all of the little tweaks that fedora does for their system.  I personally don't like all of the extra stuff that fedora compiles in, but I understand that this is a fedora system;  and if I want, building my own kernel is not very hard.

I'm glad that you took the time to work out some of the show stoppers in the kernel config, it helps a lot.
I have a couple of older machines that have their own peculiar needs, and I'd probably use a some of your config, and some of my own to make each of them better.  But in the end, would it help for the average fedora install?

Rob Wallace <rob.wallace at cae.com> wrote:

> Recently I've been evaluating the real-time PREEMPT_RT patch. I noticed that PlanetCCRMA already had RPM packages so I thought I would try them out.
> When I ran the 'cyclictest' on the ccrma kernel I noticed a lot of latency and jitter. This didn't seem normal compared to the PREEMPT_RT kernel I built myself. After investigating the issue I found certain kernel options in the ccrma kernel that should not be selected for a real-time system. These are the kernel options I changed to fix the latency issue in your build:

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