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RAM & swap usage (100GB over 30 minutes of work)

Forum|Forum|3 years ago
May 18, 2022
5 replies
5449 views

Hi all,

I am running Lightroom Classic 11.3.1 on my 2021 16" MacBook Pro (M1 Pro, 16GB RAM, 1TB SSD), on macOS Monterey 12.3.1.
I am noticing an absurd amount of RAM & swap usage. Over the course of 30 minutes of work, kernel_task and Lightroom Classic itself has written about 100GB to the SSD. This doesn't seem normal. Memory pressure is green with spikes to orange with light work, and over time it grows to consistent orange (60-75% memory pressure)

I'm working on 300 Sony a7S III files with Super Resolution applied to them beforehand (a new catalog with pre-enhanced photos already), so ~43MP DNG files around 200MB each.

Is there a solution to this high RAM & swap use?

macOS

This topic has been closed for replies.

DdeGannes

Community Expert

The Author stated in the initial post, "I'm working on 300 Sony a7S III files with Super Resolution applied to them beforehand (a new catalog with pre-enhanced photos already), so ~43MP DNG files around 200MB each."

Just thoughts out of the box, exactly what edits are being done, on individual images or batch of images?

Are you working with Auto-Sync activated?

Regards, Denis: iMac 27” mid-2015, macOS 11.7.10 Big Sur; 2TB SSD, 24 GB Ram, GPU 2 GB; LrC 12.5,; Lr 6.5, PS 24.7,; ACR 15.5,; (also Laptop Win 11, ver 24H2, LrC 15.0.1, PS 27.0; ) Camera Oly OM-D E-M1.

Ian Lyons

Community Expert

> But there does appear to be a bug somewhere that causes macOS to think an app is consuming gargantuan amounts of RAM.

Yes, Conrad C has made a good point and one that should not be dismissed. By way of example, I've seen screenshot examples comparing iStats menus indicating many GB of free memory along with even more GB of compressed memory, which in theory is also free for use when memory is under pressure. Yet, at the same time both Activity Monitor and Terminal Top are indicating that memory pressure has far exceeded all that can be used and is therefore using large amounts of swap.

Above examples are on systems with 64GB of unified memory. So, any suggestion that the OP is asking too much of too little needs to be placed in context. Sure, 32GB of memory is preferable but not an absolute minimum. If it is a mimium, then Adobe are guilty of misrepresenting the requirements of their applications, and I very much doubt they'd be so stupid.

D Fosse

Community Expert

Just a small comment about "unified memory", in response to no one in particular.

All "unified memory" means is that system and GPU share the same memory pool. So suddenly, 16 GB RAM is not nearly as much as you thought it was. The GPU may eat up a large chunk of it, but you may not know that, because it's, well, unified.

So you get swapping.

With a discrete GPU this isn't a problem, because it has its own onboard VRAM.

Other than that, I fully agree with Walt Thirion's observations re minimum requirements vs. large files.

Conrad_C

Community Expert

It’s a fine point but it is important to note that isn’t really “all” it means, because that also describes traditional integrated graphics.

By @Conrad_C

Yes, that was the implication. Lots of Windows laptops have worked this way for years. The big difference is that an Intel GPU isn't very powerful (Photoshop may or may not work with it), and it was always intended as a basic low end solution for basic needs.

I assume the M1 GPU is a lot more capable. But that also means it will use a lot more memory.

@D Fosse wrote:
I assume the M1 GPU is a lot more capable. But that also means it will use a lot more memory.

This might have changed recently, but for many years Intel integrated graphics was limited to taking no more than 1.5GB from system RAM. That alone limited it compared to Apple unified memory, which as I understand it is free to give graphics any memory that isn’t already being used as application and system RAM. So if you have an M1 with 64GB unified memory but applications need only 34GB of it, the other 28GB is available to the GPU if it wants it. So it isn’t just that unified memory might use more graphics memory…but that it actually has that option to use a lot more, for the user’s benefit.

Where we used to choose from between integrated graphics and discrete graphics, now we have integrated (most limited), unified memory (more powerful but energy-efficient), and discrete graphics (still the most powerful but also the most energy-hungry).

Conrad_C

Community Expert

I believe Ian’s answer is more correct. Although 32GB is better, 16GB Unified Memory on an M1 should be enough to get work done in Lightroom Classic with Memory Pressure not staying orange, and 64GB should be unnecessary. (The official Lightroom Classic system requirements are 8GB minimum and 16GB recommended.)

But there does appear to be a bug somewhere that causes macOS to think an app is consuming gargantuan amounts of RAM. I’ve seen it occasionally with different apps, including Photoshop and Bridge, even though the applications are not handling anything that would consume that much memory. It is not yet clear whether there is a bug on the Adobe side or the macOS side, but as Ian said, Adobe is getting a lot of reports about it and hopefully they will figure out what is going on.

Walt Thirion Photography

Known Participant

Yes, I've seen similar posts about the M1/macOS writing too much to the SSD even outside of LrC but I thought they'd fixed that with the latest update. Not positive as I'm a Windows user.

However, the OP mentions he's processing super res photos and that is a whole different story than Adobe's 'minimum requirements'. I know because I shoot medium format digital (102megapixel) with 16-bit raw files and I can see the amount of memory necessary. Even assuming Apple's claims about the M1 being more memory efficient, it's hard to get around the requirements of extremely large image processing. This is a vastly different scenario than "normal photo" processing.

C

Charl PantaleonAuthor

Participating Frequently

I agree about the different kind of demands that 16-bit medium format files impose. Although even with a more "normal" workflow, like 85% of the time I'm working on 3000-5000 image catalogs of wedding photos, from 24 to 46MP cameras. The same issues persist with massive swap usage.

Ian Lyons

Community Expert

You're correct, it's not normal, but is also proving difficult for LrC engineering to reproduce and thus fix. Unfortunatley, it gets worse in so far as there aren't any guaranteed pain free workarounds at present, although one that seems to help users reporting similar issues is to turn GPU acceleration Off in LrC Performance preferences. Doing so shouldn't hurt you too much since Adobe use the Apple Neural Engine (ANE) for Enhanced Raw and Super Resolution with the GPU primarily being used for rendering the display. The same applies to the Ai masks. Where you 'might' find a slow down are LrC features that make heavy use of the GPU for processing and working on images that have alrerady been processed in app such as DxO Pure Raw or Ai apps from On1, Topaz, etc. Even so, I encourage you try switching off the GPU and sharing your observations as same may help others in a similar situation.

C

Charl PantaleonAuthor

Participating Frequently

Turning off GPU acceleration doesn't prove much help. Lightroom eats less system RAM (say from 12 GB to around 5-7 GB) but swap use is still excessive.

Ian Lyons

Community Expert

How are you measuring memory use? Activity Monitor, Top or third party app

Walt Thirion Photography

Known Participant

16GB of system RAM is pretty light to work on super res files which is why you are seeing a lot of swapping to the SSD.

To me, 32GB would be the absolute minimum, 64GB would be a lot better.

C

Charl PantaleonAuthor

Participating Frequently

Super Resolution is not a frequent part of my workflow. My work usually involves weddings with 3000-5000 images per project / catalog (after culling rejects from 7000-15000!). Still, Lightroom eats up a lot of RAM and swap in that scenario. In comparison, Capture One usually consumes 7-12 GB of RAM with very little swap use.

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