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macOS 10.14.6 Serious CPU issues / Background Processes

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macOS 10.14.6 Serious CPU issues / Background Processes

Postby Vaultnaemsae » Thu Aug 29, 2019 9:44 pm

Ableton Live 10 user here. My MacBook Pro Retina mid-2015 (macOS 10.14.6) is experiencing problematic processes during audio processing/recording that result in heavy glitching and breakup of audio signal and high readings on the CPU meter in Ableton live (up to 80%ish). Processor is a 2.5GHz Intel i7 (quad core with turbo boost/4 virtual cores), RAM is 16GB…I really think it should be able to handle what I’m throwing at it and it usually does — until it doesn’t.

The background processes I can identify as problematic are:
-Ableton Index — CPU readings up to 90% but usually only for 20 seconds after starting Live 10;
-backupd-helper/mediaanalysisd/photoanalysisd/Photos Agent — I assume these are related…they can be running anywhere from 30% up to 140% according to Activity Monitor;
-kernel_task — I’ve seen it reach 350% twice and 800% twice in Activity Monitor — it only happens when running Live 10 — I think this is the main problem.

Some other things:
-I had a 2011 iMac connected as an external display via Thunderbolt. Removing it seems to have temporarily improved the situation today but I've also had problems without it being connected;
-I do use a complex aggregate device consisting of 5 or 6 audio devices that operate at different sample rates (either 44.1 or 48kHz)— but they work together fine — until they stop working fine;
-I’ve had problems in the past with Automatic Graphics switching activated…it’s off now.

In my tests I was playing in realtime 4 VSTs on individual MIDI tracks: Syntronik, Audulus, Ableton's External Instrument tool, Studiomux (w/ iPhone). This doesn't seem like a big ask considering what I've seen people do on older machines.

It’s killing my creativity. Right now with nothing but Activity Monitor open and all other apps closed the system is 98-99% idle. I really hope somebody can give me some advice here. Thanks in advance.
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Re: macOS 10.14.6 Serious CPU issues / Background Processes

Postby cyrano.mac » Sat Aug 31, 2019 2:21 pm

Vaultnaemsae wrote:-I do use a complex aggregate device consisting of 5 or 6 audio devices that operate at different sample rates (either 44.1 or 48kHz)— but they work together fine — until they stop working fine;

Why different sampling rates?

You're forcing Core audio to resample those on the fly. That works flawlessly for one or two streams. Anything over that is user error.

Rule number one: align your hardware. I can't think of any reason why you would have different sampling rates in a project, let alone in an aggregated array of devices.
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Re: macOS 10.14.6 Serious CPU issues / Background Processes

Postby MOF » Sat Aug 31, 2019 2:41 pm

-I do use a complex aggregate device consisting of 5 or 6 audio devices that operate at different sample rates (either 44.1 or 48kHz)— but they work together fine — until they stop working fine;

Why different sampling rates?

You're forcing Core audio to resample those on the fly. That works flawlessly for one or two streams. Anything over that is user error.

Rule number one: align your hardware. I can't think of any reason why you would have different sampling rates in a project, let alone in an aggregated array of devices.

What are these devices, how are they connected and do you have a master clock to synchronise them also did you have a long period of use without problems using this configuration?
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Re: macOS 10.14.6 Serious CPU issues / Background Processes

Postby Vaultnaemsae » Sun Sep 01, 2019 9:02 pm

Hi, thanks for the replies.

I'm using it this way as some of the different devices have locked sample rates. I typically keep devices at 48kHz where possible but the first two devices are older and only operate at 44.1kHz. One device only operates at 48kHz and the others are flexible.

I originally wanted to use SPDIF to connect two of the devices (44.1 -> 48) but obviously that wouldn't work without some kind of converter. I read that macOS can do sample rate conversion on the fly but there is very little documentation about the details. So I tried to do it this way but have met with varying degrees of success. There have been periods where it has worked for hours on end but only with two devices (i.e. 1 x 44.1kHz and 1 x 48kHz).

All devices are connected over USB via two daisy-chained 4-socket hubs (my MacBook only has 2 USB ports).

The Axe-Fx is the master clock and I set all slave devices' drift correction to 'on'.

I think I need to get into some testing with smaller aggregates and perhaps experiment with changing the clock source. That, or just simplify the routing -- maybe use some analog connections.
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Re: macOS 10.14.6 Serious CPU issues / Background Processes

Postby Dave Rowles » Mon Sep 02, 2019 11:28 pm

I think this is a sample rate issue. I've had the similar things happen when I've got the wrong sample rate selected on a project for the interface.

One desk I use for live recordings is fixed at 96, and normally I run at 48. It' copes for about a minute and then throws a fit.

I'd seriously look into connecting things a slightly different way, or replacing the gear that requires different clock. Do they all have to be connected via USB? Could some be connected via audio instead?

I imagine on older machines they are controlling via MIDI instead of USB, or things are connected in a more analogue fashion.

If you give us a run down of the gear and how it's connected we could help to see if there's a better way of getting everything to talk to each other.
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Re: macOS 10.14.6 Serious CPU issues / Background Processes

Postby Vaultnaemsae » Wed Sep 04, 2019 4:51 am

I spent some time working on this problem yesterday and got it all working (even at a 64 sample buffer setting) without pops n crackles -- and on 2 different computers. It's more or less reliable now. It’s also a very flexible guitar performance/recording rig ever.

The one thing that appears to have had a major impact on performance was using a custom 'Options.txt' file in the Ableton Live 10 Preferences folder that lowers the FPS — recommendations suggested setting it to 30 but I set it to a more extreme 15 and it seemed to immediately almost halve my CPU usage.

For anybody interested I'll describe the setup.

On the USB HUB (and following the order in the aggregate device):
1. Roland VG-99 (44.1kHz) Drift correction "ON"
2. Boss GP-10 (44.1kHz) Drift correction "ON"
3. Axe-Fx II XL+ (48kHz) Set as Clock Source (N.B. the Axe-Fx is in USB Input mode)
4. iConnectAUDIO4+ Port 2 of 2 (48kHz) Drift correction "ON" *Port 1 of 2 is an iPad for iOS synths
5. ATR2100-USB Mic (48kHz) Drift correction "ON"

My guitar runs into a Roland US-20 13-pin splitter box which allows [A / B / A+B] for using the the Roland VG-99 / Boss GP-10 in parallel. Setting up the aggregate this way should enable reamping on devices 1, 2 and 3. If reamping wasn't a concern, I would’ve just used analog connections. but I wanted to be able to access all functions fairly simply and quickly. Also, I had to adjust the buffers of the Roland/Boss devices individually in their respective driver interfaces under the macOS System Preferences.

In Ableton Live 10 I can now route anything anywhere. Much to my surprise, the conflicting sample rates seem to not be causing any problem at all at this time. But I wonder, what’s going to go wrong next?!?!?

Some issues I encountered along the way:
- I can confirm that using macOS’ target display mode disrupts regular CPU performance. Once connected, I have to continuously increase the buffer every time audio starts crackling. I think I'll give up on this possible use case scenario — which is a pity because I like the idea of a 2nd monitor.

- Another issue that I think was contributing to the audio mess was that I occasionally use ‘Studiomux Generator’ (VST) and the audio device it creates was defaulting my iPhone's sample rate to 44.1kHz every time I reconnected it. Manually readjusting it to 48kHz seemed to clean things up a bit. Studiomux is a bit hit and miss but it’s great when it works.

- When I tried to set up the same Live set on computer 2 (2011 iMac on High Sierra 10.13.6) the iCA4+ would crash Live every time I touched (yes, touched!) the iCA4+ or adjusted it’s routing in the Live set. I created a new aggregate for computer 2 without the iCA4+. I guess I’ll use IDAM or Studiomux instead of the iCA4+ on this device as needed.
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Re: macOS 10.14.6 Serious CPU issues / Background Processes

Postby cyrano.mac » Thu Sep 05, 2019 4:03 pm

Vaultnaemsae wrote:I think I need to get into some testing with smaller aggregates and perhaps experiment with changing the clock source. That, or just simplify the routing -- maybe use some analog connections.

You're up against what's reasonably possible with aggregation.

Two devices usually work perfectly. 3 to 6 also, if they don't make Core audio resample on-the-fly.

There's also the slight possibility that one of your devices has an unstable clock and wrecks things. Usually, that's the newer device. Strangely, clocks get more stable as they get older.

So, yes, analog connections might be the easiest solution.

I've experimented a lot with aggregation, even into the absurd. One thing I've learned is that there is a limit. That's to be expected, of course. But it isn't a clear line. Every extreme case is extremely different. I've built a setup with six almost identical devices (at the same sampling rate), without any problems. In that case, I hit USB2's channel limit. With different devices, I never got past four. And that's even with the same sample rate on every device.

Mind you, that was with a Mac that was tuned for audio, but less powerful than yours. It was a Core2 Duo, IIIRC. And it was with Snow Leopard. That also will make a difference, as Mojave always seems ready to talk to the Cloud...
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