As of today (with .NET 7 and 8 preview) 120MB base footprint memory usage by .NET is indeed surprising. A few questions:
- How are you exactly launching the workload?
- How much memory does your system have?
- Could you try running it with .NET 7 instead?
The last two are especially relevant because in the recent versions each release got extra work to reduce memory footprint on Linux (mostly because it's an important metric for container deployments).
Overall, 120MB sounds about right if you are launching a .NET 6 workload with some extra instrumentation attached while the runtime picks Server GC which is much more enthusiastic about allocating large segments of memory, especially if the system has large amount of RAM.
As for Tasks - C# tasks are in many ways similar to Rust's futures (both are yielding-to-the-caller state machines) and take very little memory, which scales directly with the amount of variables that persist across "yield points" (which you have none).
> Overall, 120MB sounds about right if you are launching a .NET 6 workload with some extra instrumentation attached while the runtime picks Server GC which is much more enthusiastic about allocating large segments of memory, especially if the system has large amount of RAM.
Also if you have lots of CPU cores then the CLR will (pre-)allocate up-to ~10MB/core for per-hardware-thread GC heaps. So my 16-core (32-thread) desktop will run every .NET program with a starting (OS-level) memory usage of ~200MB for a Hello, World program - though actual total GC usage will be < 1 MB.
Using .NET 6 is perfectly fine! It is the latest LTS after all, it's just that on machines with a lot of RAM the GC can indeed pre-allocate quite a bit of memory if, based on hardware configuration, it chooses to use Server GC. This, however, is being tuned with each subsequent release hence I'm curious to see the numbers on 7 on the author's hardware.
- How are you exactly launching the workload?
- How much memory does your system have?
- Could you try running it with .NET 7 instead?
The last two are especially relevant because in the recent versions each release got extra work to reduce memory footprint on Linux (mostly because it's an important metric for container deployments).
Overall, 120MB sounds about right if you are launching a .NET 6 workload with some extra instrumentation attached while the runtime picks Server GC which is much more enthusiastic about allocating large segments of memory, especially if the system has large amount of RAM.
As for Tasks - C# tasks are in many ways similar to Rust's futures (both are yielding-to-the-caller state machines) and take very little memory, which scales directly with the amount of variables that persist across "yield points" (which you have none).