Re: [gentoo-user] Gentoo realtime-preempt kernel?
On Thu, 21 Apr 2005, Mark Knecht wrote: I'm just poking around looking at kernels again this morning. Maybe I've missed it but I cannot find one in portage that uses Ingo Molnar's realtime-preempt patches. Is there one? I am now using both ck-sources as well as the realtime-lsm module from portage. Many thanks to who ever helped with getting that in there. Are there enough people using Gentoo for realtime audio that it would warrent some sorrt of specialized kernel project? I expect so. Is there interest? How do we start one? I dont have answers but a counter-question: have you tried the pre-emptible kernel configs for 2.6 kernels? -- -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] Gentoo realtime-preempt kernel?
On Thu, 21 Apr 2005 09:49:50 -0700 Mark Knecht [EMAIL PROTECTED] wrote: Hi, I'm just poking around looking at kernels again this morning. Maybe I've missed it but I cannot find one in portage that uses Ingo Molnar's realtime-preempt patches. Is there one? I am now using both ck-sources as well as the realtime-lsm module from portage. Many thanks to who ever helped with getting that in there. Are there enough people using Gentoo for realtime audio that it would warrent some sorrt of specialized kernel project? I expect so. Is there interest? Yes, there is interest. At least, I'm interested. I've been using 2.6.10-gentoo-r6 with CONFIG_SECURITY_REALTIME=m using the patch from here: http://www.joq.us/realtime/ at the suggestion of someone on this list... and getting some good low latency in, say, jack rack. But, It seems there's more than one way to do this. I was _trying_ to find a patch I could apply to the 2.6.11 kernel for realtime pre-emption, but this isn't it, I guess. I know read about Molnar's realtime-preempt patches somewhere along the way, maybe even tried to apply them to the gentoo kernel sources, but this didn't work out. I'm essentially clueless in this dept. I also read somewhere along the way that maybe 2.6.11 isn't as good, yet, as 2.6.10 for audio. But I don't believe everything I read. Anyway, thanks for bringing this up. It'd be great to have a ready-made Gentoo realtime-preempt kernel. -- |\ /| | | ~ ~ | \/ | |---| `|` ? ||ichael | |iggins\^ / michael[dot]higgins[at]snet[dot]net -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] Gentoo realtime-preempt kernel?
On 4/21/05, A. Khattri [EMAIL PROTECTED] wrote: On Thu, 21 Apr 2005, Mark Knecht wrote: I'm just poking around looking at kernels again this morning. Maybe I've missed it but I cannot find one in portage that uses Ingo Molnar's realtime-preempt patches. Is there one? I am now using both ck-sources as well as the realtime-lsm module from portage. Many thanks to who ever helped with getting that in there. Are there enough people using Gentoo for realtime audio that it would warrent some sorrt of specialized kernel project? I expect so. Is there interest? How do we start one? I dont have answers but a counter-question: have you tried the pre-emptible kernel configs for 2.6 kernels? Yes, absolutely. They work, but they do not work as well as the kernels I get for my FC2 boxes from here: http://ccrma.stanford.edu/planetccrma/software/ That said I have not characterized the differences in a long time so maybe that's worth a day to see what the results end up looking like. However a real characterization would require patching some kernel (gentoo-sources?) with Ingo's patches and seeing what the differences are. Not sure if my skill set is up to that by myself. Thanks for the response, Mark -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] Gentoo realtime-preempt kernel?
On 4/21/05, michael higgins [EMAIL PROTECTED] wrote: On Thu, 21 Apr 2005 09:49:50 -0700 Mark Knecht [EMAIL PROTECTED] wrote: Hi, I'm just poking around looking at kernels again this morning. Maybe I've missed it but I cannot find one in portage that uses Ingo Molnar's realtime-preempt patches. Is there one? I am now using both ck-sources as well as the realtime-lsm module from portage. Many thanks to who ever helped with getting that in there. Are there enough people using Gentoo for realtime audio that it would warrent some sorrt of specialized kernel project? I expect so. Is there interest? Yes, there is interest. At least, I'm interested. I've been using 2.6.10-gentoo-r6 with CONFIG_SECURITY_REALTIME=m using the patch from here: http://www.joq.us/realtime/ at the suggestion of someone on this list... and getting some good low latency in, say, jack rack. What are you seeing? But, It seems there's more than one way to do this. I was _trying_ to find a patch I could apply to the 2.6.11 kernel for realtime pre-emption, but this isn't it, I guess. No, it isn't. This is a patch that allows you to run with realtime privileges as a normal user. This is good but it's no the complete story I think. I know read about Molnar's realtime-preempt patches somewhere along the way, maybe even tried to apply them to the gentoo kernel sources, but this didn't work out. I'm essentially clueless in this dept. OK, so Ingo's patches are here: (at least I think!) http://people.redhat.com/mingo/ He does both low-latency patches and realtime-preempt patches. I think they are both used in the PlanetCCRMA kernels, along with the realtime-lsm modules to allow a user to take full advantage of this stuff. That's the way I understand it anyway. I also read somewhere along the way that maybe 2.6.11 isn't as good, yet, as 2.6.10 for audio. But I don't believe everything I read. Anyway, thanks for bringing this up. It'd be great to have a ready-made Gentoo realtime-preempt kernel. I think so. First we should make sure we know what we want and then possibly try writing an ebuild to make it more or less automatic. Thanks, Mark -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] Gentoo realtime-preempt kernel?
On 4/21/05, michael higgins [EMAIL PROTECTED] wrote: On Thu, 21 Apr 2005 12:06:12 -0700 Mark Knecht [EMAIL PROTECTED] wrote: On 4/21/05, michael higgins [EMAIL PROTECTED] wrote: On Thu, 21 Apr 2005 09:49:50 -0700 Mark Knecht [EMAIL PROTECTED] wrote: using the patch from here: http://www.joq.us/realtime/ at the suggestion of someone on this list... and getting some good low latency in, say, jack rack. What are you seeing? Hearing, actually. I've only compared to the playability of my rig on 'doze. No benchmarking. It's just slightly better. I feel it could be better still. '-) I look forward to any new clues on this list. Well, what I meant was what sort of Jack settings are you using and what are you seeing in terms of xruns? I can run some of my systems with patched kernels and realtime-lsm (be they Gentoo or FC2/PLanet) at 128/2 or even 64/2. My laptop onboard sound chip will actually run 16/2 (well under 1mS latency) with a custom patched kernel. I don't remember doing much better than 512/2 or possibly 256/2 for short periods of time with an unpatched kernel. That said the info above is definitely NOT apples to apples since these are different systems, different sound cards and different distros and different setups. I'd like to get some consistency to all of this. I do have a very ck-sources kernel that seems to work pretty well but I haven't actually done a session with it so I really don't want to say it's ready. It does compile and run well under low loads though. - Mark -- gentoo-user@gentoo.org mailing list
