# RealityScan 2.2 for Linux: alignment 3–5x slower in a container than on Windows (thousands of threads, few cores used)

**URL:** <https://forums.unrealengine.com/t/realityscan-2-2-for-linux-alignment-3-5x-slower-in-a-container-than-on-windows-thousands-of-threads-few-cores-used/2855013>\
**Category:** Pipeline & Plugins\
**Tags:** Linux, linux-build, unreal-engine\
**Created:** [November 13, 2026, 10:08am UTC](https://forums.unrealengine.com/t/realityscan-2-2-for-linux-alignment-3-5x-slower-in-a-container-than-on-windows-thousands-of-threads-few-cores-used/2855013 "2026-11-13T10:08:02Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![OldRaven](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@OldRaven](https://forums.unrealengine.com/u/OldRaven)\
**Post date:** [November 13, 2026, 10:08am UTC](https://forums.unrealengine.com/t/realityscan-2-2-for-linux-alignment-3-5x-slower-in-a-container-than-on-windows-thousands-of-threads-few-cores-used/2855013/1 "2026-11-13T10:08:02Z")

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Hello RealityScan team,

I am testing RealityScan 2.2 for Linux (realityscan\_2.2-1 .deb, CLI headless) for automated cloud processing of drone projects. Installation, Epic login and headless processing all work, but alignment is much slower than on my Windows workstation with the same dataset and settings.

Setup

- Docker container on RunPod, image nvidia/cuda:12.8.1-base-ubuntu24.04, NVIDIA driver 595.91, NVIDIA\_DRIVER\_CAPABILITIES=all
- GPUs tested: RTX 4090, RTX PRO 4500 and RTX PRO 6000 Blackwell; Vulkan sees the NVIDIA GPU, libcuda is present
- CPU: the container has a cgroup quota of 8–32 cores on hosts with 64–256 cores
- Wine esync enabled (“esync: up and running”, ulimit -n 524288)
- realityscan-cli -headless -silent … -addFolder … -align (sfmImageDownscaleFactor=2, sfmImagesOverlap=Medium, camera priors from EXIF/RTK)

Dataset: 1,889 DJI Mavic 4E images (RTK)

Observations

1. Importing the images runs on a single core for 7–10 minutes.
2. Alignment (progress task 65537): on Windows it reaches 81% after about 37 minutes. In the container it reaches only 33%–57% after 25–70 minutes, i.e. 3–5x slower.
3. RealityScan reports “Using 64 CPU cores” (the host core count, not the container quota). Without restriction it uses all quota cores but is heavily throttled by the cgroup quota.
4. When I restrict the CPU affinity to the quota (27 cores), throttling disappears, but RealityScan then only uses 3–5 cores, while the process has 3,000–4,600 threads. wineserver stays below 2% CPU. The GPU is at 0% during alignment.

Questions

- Is this behaviour known for RealityScan for Linux in containers / with CPU quotas?
- Is there a setting (CLI -set or app setting) to limit the number of worker threads or CPU cores RealityScan uses?
- Are there recommended Wine/CrossOver or container settings for headless servers (e.g. esync/fsync, CPU topology, thread pool size)?
- Is the Linux version intended to reach performance comparable to Windows for alignment?

I can provide the progress files, job logs and the exact command line if helpful.

Kind regards,  
Peter