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08-05-2018, 10:11 AM | #1 |
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What is your experience with the preempt_rt patch vs. an rt-linux kernel?
Looking forward to getting my desktop set up for best low latency audio performance and some general purpose use. What has been your experience with the preempt_rt patch vs. rt kernel? Most recommendations I see these days say to go with a regular kernel with the preempt_rt patch, but along with those recommendations is a lack of elaboration. It seems to me that an rt kernel has the potential for dialing in a best balance of solid audio reliability and lowest latency, where the preempt_rt patch provides solid audio reliability for a general purpose machine albeit a little more latency.
Anyone done any comparison testing? Any tips to share? Also on that topic, what stable roundtrip latency are you seeing with your machine/audio device, whether you are using a regular kernel, a regular kernel with preempt_rt applied, or a a realtime kernel? And for those who are running a realtime kernel, have you ran into any major issues for general purpose use?
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It's time to take a stand against the synthesizer. Last edited by brainwreck; 08-05-2018 at 10:19 AM. |
08-05-2018, 10:56 AM | #2 |
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After a little more reading: Are actual realtime kernels still being maintained/developed today?
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It's time to take a stand against the synthesizer. |
08-05-2018, 11:57 AM | #3 |
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Hi,
I just installed Ubuntu Studio 18.04 lowlatency kernel 4.15.0-29 couple of days ago. I have a cheap Behringer U-PHORIA UMC22 USB audio interface and running that with these settings: Sample Rate: 48000 Buffer Size: 512 Periods/Buffer: 3 Gives 10.7ms latency, works great with the VST instruments i use: * AmpleSound Acoustic * AmpleSound Bass * Keyzone Classic, piano * Stock Reaper Plugins and a bunch of free ones * HoRNet plugins * SForzando Soundfonts, like violin, cello, piano and other instruments I do everything in MIDI these days and I get pretty good sound I might add. Good enough for me. 15-30 tracks with no errors so far, everything's is running smooth as butter. I have a Lenovo IdeaCentre 23" All-In-One computer with 8GB RAM and a SSD 256GB. I might upgrade it to 16GB RAM in the future, but it runs well right now.
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OS: Manjaro KDE Plasma, Reaper For Linux (64Bit) native linux-vst plugins, LSP-Plugins, TpL-Plugins, Harrison's AVA & VST Plugins. Behringer U-PHORIA UMC22. |
08-05-2018, 12:16 PM | #4 | |
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http://www.linux-magazin.de/ausgaben...-echtzeitig/3/ (Test from 2008. picture, from page 3, see appendix.)
https://wiki.linuxaudio.org/wiki/real_time_info, https://linuxmusicians.com/viewtopic.php?f=26&t=9845 Quote:
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08-05-2018, 12:55 PM | #5 | ||
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Quote:
From a translation of that page, I see this near the end of the article: Quote:
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It's time to take a stand against the synthesizer. Last edited by brainwreck; 08-05-2018 at 01:09 PM. |
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08-05-2018, 02:31 PM | #6 |
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Technically, it's too complex for me, I can't explain it. My English is also too bad. SRY
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08-05-2018, 03:21 PM | #7 |
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I've noticed a slight improvement in latency and xruns but not enough to be very noticeable. Not really worth the effort vs a low latency kernel in my opinion but it depends what your target is and undoubtedly what your hardware/setup is.
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08-05-2018, 03:58 PM | #8 | ||
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I don't know what to make of this:
Quote:
Anyone have a definitive source on untangling this? Edit: Found more info here: Quote:
Vanilla kernel comes from original linux kernel devs. Generic kernel (stock kernel) comes from distro devs. And so: Generic, preempt_rt, rt, and lowlatency are all of the distro specific kernel source, with preempt_rt being soft real-time, rt being hard real-time, and lowlatency being soft real-time with more agressive config. Vanilla and realtime are of the original linux source, with realtime being hard real-time. Anyone confused yet?
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It's time to take a stand against the synthesizer. Last edited by brainwreck; 08-05-2018 at 04:26 PM. |
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