grr_cli/core/
runtime.rs

1use tokio::sync::OnceCell;
2use tracing::warn;
3
4#[derive(Debug, Clone, Copy, PartialEq, Eq)]
5pub struct RuntimeFeatures {
6    pub io_uring: bool,
7    pub num_cpus: usize,
8}
9
10static RUNTIME_FEATURES: OnceCell<RuntimeFeatures> = OnceCell::const_new();
11
12pub async fn detect_runtime_features() -> RuntimeFeatures {
13    *RUNTIME_FEATURES
14        .get_or_init(|| async {
15            let io_uring = match tokio::task::spawn_blocking(detect_io_uring).await {
16                Ok(value) => value,
17                Err(error) => {
18                    warn!("runtime feature probe failed: {error}");
19                    false
20                }
21            };
22            RuntimeFeatures {
23                io_uring,
24                // std since 1.59; honors affinity and cgroup limits like
25                // num_cpus did, and drops a dependency.
26                num_cpus: std::thread::available_parallelism()
27                    .map_or(1, std::num::NonZeroUsize::get),
28            }
29        })
30        .await
31}
32
33fn detect_io_uring() -> bool {
34    #[cfg(target_os = "linux")]
35    {
36        if let Ok(release) = std::fs::read_to_string("/proc/sys/kernel/osrelease")
37            && let Some(major) = release.split('.').next()
38            && let Ok(major) = major.parse::<u32>()
39            && major < 5
40        {
41            return false;
42        }
43        io_uring::IoUring::new(1).is_ok()
44    }
45
46    #[cfg(not(target_os = "linux"))]
47    {
48        false
49    }
50}
51
52#[cfg(test)]
53mod tests {
54    use super::*;
55
56    #[tokio::test]
57    async fn io_uring_report_matches_target_gate() {
58        let features = detect_runtime_features().await;
59        assert!(!features.io_uring || cfg!(target_os = "linux"));
60    }
61}
grr_cli/core/runtime.rs

grr_cli/core/
runtime.rs
