System Resources

Weasis routinely handles studies far larger than its memory: a CT or MR series is hundreds of slices, a digital mammography image is tens of megabytes, a 3D volume is hundreds of megabytes. The System resources panel shows, in real time, how much of the machine Weasis is using, whether the hardware matches your daily practice, and β€” when it does not β€” what to upgrade.

Open it from the menu Help > System resources.

The panel does not change anything by itself. It is a diagnostic view: it observes, measures across all your sessions, and gives a verdict you can act on.

How memory works in Weasis

To read the panel, it helps to know that Weasis uses memory in two separate pools:

  • JVM heap β€” holds the user interface, the DICOM metadata and temporary copies of pixels. Its maximum size is fixed when Weasis starts.
  • Native image memory β€” holds the decoded pixel data of images. This is the pool that grows when you open large studies. It is not part of the heap; it is sized from the physical memory of the machine.

A third pool, GPU memory (VRAM), is used only by the 3D viewer.

This separation is why a single “memory” number is not enough β€” and why the panel shows both pools side by side.

Reading the panel

The dialog refreshes every two seconds while it is open. It has five sections.

Hardware

A static description of the machine:

Row Meaning
Operating system OS name, version and architecture
CPU cores Number of processor cores available to Weasis
Physical memory Total RAM of the machine
JVM heap maximum Upper bound of the heap pool
Native memory budget Upper bound of the decoded-image pool
Graphics processor The GPU detected by the 3D viewer, and its OpenGL version
Note

The graphics processor row stays not assessed until a 3D view has been opened at least once β€” Weasis only learns the GPU when the 3D engine starts. If it reports software rendering, the 3D viewer is running without GPU acceleration and will be slow; install or enable a proper graphics driver.

Live pressure

Three bars showing current use, each with its peak value for the session:

  • JVM heap β€” interface and metadata memory.
  • Native image memory β€” decoded images currently cached.
  • CPU load β€” processor use by Weasis.

A bar turning red above 90 % means that pool is close to its limit. Native image memory reaching its limit is normal and harmless: Weasis simply drops the least-recently-seen images from the cache and reloads them transparently when you scroll back. A heap bar staying near 100 %, on the other hand, is a real warning sign.

Assessment

The verdict β€” the heart of the panel. Each line is rated with one of four levels:

Level Color Meaning
Collecting… neutral Not enough activity yet to judge β€” keep using Weasis
Sub-optimal red The resource limited Weasis; the machine should have more
Optimal green The resource matched the workload well
Abundant blue The resource was barely used; the machine has spare capacity
  • Overall β€” the worst of the rows below.
  • Memory β€” based on real failure signals, not on raw usage: out-of-memory errors, a 3D volume that had to spill to disk, or sustained garbage-collection overhead. A rare event is tolerated; a recurring one turns the verdict red.
  • CPU β€” sub-optimal on 2 cores or fewer; abundant on 8+ cores left mostly idle.
  • Recommended upgrade β€” see below.
Info

The verdict is cumulative across all your sessions, not just the current one. It stays Collecting… until Weasis has run long enough and done enough work to judge fairly, so a fresh installation will not show a verdict immediately.

Workload

What the heaviest study you opened actually demanded: the largest image (in megabytes) and the largest volume (in number of slices). These explain why a verdict came out the way it did.

Events (all sessions)

The counters behind the memory verdict, accumulated over every session:

Counter What it means
Session uptime This session, then total time and number of sessions
Cache evictions Images dropped from the cache and reloaded β€” informational, not a problem
Out-of-memory errors The heap ran out β€” turns red when it is driving a sub-optimal verdict
Volume disk spills A 3D volume did not fit in memory and was written to disk β€” slow
Garbage-collection overhead Share of time spent reclaiming heap memory; above ~10 % the heap is too small

A non-zero count is not necessarily a problem β€” the panel colors a counter red only when it is the signal currently causing a sub-optimal memory verdict.

Acting on the recommendation

When Memory or CPU is sub-optimal, the Recommended upgrade line gives a concrete target. Weasis distinguishes a configuration problem from a hardware one:

  • A larger heap (-Xmx) β€” shown when the machine has free RAM but Weasis was not allowed to use enough of it. This is fixed by changing a setting, not by buying hardware.
  • More RAM β€” shown when the heap is already a fair share of physical memory: the machine itself is the limit.
  • More CPU cores β€” shown when too few cores slowed image decoding and reconstruction.

Increasing the memory limits

The heap maximum and the native-memory budget are controlled by start-up options. The simplest way to raise the heap is the -Xmx option; the native-image pool is controlled by a Weasis property:

Option / property Effect Default
-Xmx<size> Absolute maximum of the JVM heap, e.g. -Xmx4g 25 % of RAM
weasis.native.memory.percent Native image memory as a percentage of RAM (1–90) 50

For an installed Weasis, edit the java-options of the application configuration (for example app/Weasis.cfg next to the installation). For a study workstation that opens large studies, raising the native-memory percentage keeps more images cached and avoids reloads:

weasis.native.memory.percent=70
Warning

The heap and the native pool share the same physical RAM, so keep their combined share comfortably below 100 %. Raising the heap reduces the room left for the image cache. On a machine with little RAM, raising one means lowering the other.

The full set of memory parameters is described in the Memory Management developer guide.

Exporting the report

The Copy report button places a plain-text summary of the whole panel on the clipboard β€” hardware, verdict, recommendation and event counters. Paste it into a bug report or a message to your IT department when asking for a hardware upgrade.

Tip

The verdict and the limiting events are also written to the Weasis log files in <user home>/.weasis/log/, and the cumulative statistics are kept in <user home>/.weasis/resource-stats.properties. You do not need the panel open for Weasis to keep measuring.