sysinfo Rust Library

In v0.33, the following methods were renamed to refresh:

• Users::refresh_list
• Groups::refresh_list
• Components::refresh_list
• Networks::refresh_list
• Disks::refresh_list

Note that all of these (except Users::refresh and Groups::refresh) now require a boolean argument to specify whether sysinfo should keep removed items.

Starting in v0.31, you can reduce build size and time by disabling default features and enabling only what you need. For example, to only include network information:

sysinfo = { version = "0.31", default-features = false, features = ["network"] }

In v0.30, all traits were removed. You no longer need to import extension traits like SystemExt to use methods on System.

Before v0.30:

use sysinfo::{System, SystemExt};

// `SystemExt` is needed for both `new` and `refresh_processes`.
let mut s = System::new();
s.refresh_processes();

In v0.30+:

use sysinfo::System;

// No need for `SystemExt` anymore!
let s = System::new();
s.refresh_processes();

In v0.31, System::refresh_process, System::refresh_process_specifics, and System::refresh_pids were removed. They are replaced by System::refresh_processes and System::refresh_processes_specifics, which take a ProcessesToUpdate argument.

To refresh specific PIDs:

use sysinfo::{ProcessesToUpdate, System};

let pid = 1337;
let mut s = System::new();
s.refresh_processes(ProcessesToUpdate::Some(&[pid.into()]));

To refresh all processes:

use sysinfo::{ProcessesToUpdate, System};

let mut s = System::new();
s.refresh_processes(ProcessesToUpdate::All);

In v0.34, the multithread feature is disabled by default to avoid issues with the rayon crate.

System::physical_core_count is now an associated function and no longer requires a System instance.

System::refresh_all and System::refresh_specifics now automatically remove dead processes. To prevent this behavior, use System::refresh_processes_specifics directly.

Building directly on Raspberry Pi can be difficult. It is recommended to cross-compile on a host machine (e.g., Ubuntu) using the armv7-unknown-linux-gnueabihf target.

1. Install the toolchain:

   sudo apt install gcc-multilib-arm-linux-gnueabihf

2. Configure Cargo to use the linker:

   cat << EOF > ~/.cargo/config
   [target.armv7-unknown-linux-gnueabihf]
   linker = "arm-linux-gnueabihf-gcc"
   EOF

3. Build the target:

   rustup target add armv7-unknown-linux-gnueabihf
   cargo build --target=armv7-unknown-linux-gnueabihf

To use sysinfo to retrieve system information, you must first instantiate a System struct and call a refresh method. Most information (like CPU usage or memory) is calculated based on the difference between the current and previous values, so you should keep a single instance of System alive throughout your program rather than recreating it.

To ensure all lists (like CPUs and processes) are populated on the first run, use System::new_all().

Follow these best practices to improve performance and resource usage:

1. Use specific refreshes: Instead of refresh_all(), use refresh_specifics(...) methods to update only the subset of information your application requires.
2. Reuse the System instance: Avoid recreating the System struct. Reusing the same instance allows the library to compute deltas (like CPU usage) and avoids repeated memory allocations for lists like processes.
3. Manage file descriptors: If your application requires a high number of file descriptors, call sysinfo::set_open_files_limit(0); to prevent sysinfo from consuming them for performance optimization.
4. Feature Flags: The multithread feature enables multi-threaded data collection but may increase memory usage on certain platforms like macOS.

By default, sysinfo may use APIs prohibited by Apple's App Store policies. To ensure compatibility:

• Use the apple-app-store feature flag to disable prohibited features. This automatically enables the apple-sandbox feature.
• If you are running in a sandbox outside of the App Store, you can enable the apple-sandbox feature alone.