trueno/registry/
cuda.rs

1//! CUDA factory: `libcuda.so.1` through the driver API, never cudart (REG-2).
2use super::{Api, BackendEntry, BackendFactory, BackendKind, MemKind, Reason, Source, Status};
3use trueno_gpu::driver::{device_count, CudaContext};
4
5/// Discovers NVIDIA devices through the dlopen'd driver.
6pub struct CudaFactory;
7
8const LIB: &str = "libcuda.so.1";
9
10impl BackendFactory for CudaFactory {
11    fn kind(&self) -> BackendKind {
12        BackendKind::Cuda
13    }
14
15    fn discover(&self) -> Vec<BackendEntry> {
16        // Three distinct, reachable reasons (review quorum 2026-09-06, lane 1:
17        // `cuda_available()` folds a load failure, a probe error and zero devices
18        // into one bool, which made two arms dead). dlopen first, then count.
19        if trueno_gpu::driver::sys::CudaDriver::load().is_none() {
20            return vec![BackendEntry::unavailable(
21                BackendKind::Cuda,
22                Api::CudaDriver,
23                Source::Dlopen(LIB.to_string()),
24                Reason::DriverNotFound { path: LIB.to_string() },
25            )];
26        }
27        let n = match device_count() {
28            Ok(n) => n,
29            Err(e) => {
30                return vec![BackendEntry::unavailable(
31                    BackendKind::Cuda,
32                    Api::CudaDriver,
33                    Source::Dlopen(LIB.to_string()),
34                    Reason::ProbeFailed { error: format!("cuDeviceGetCount: {e:?}") },
35                )]
36            }
37        };
38        if n == 0 {
39            return vec![BackendEntry::unavailable(
40                BackendKind::Cuda,
41                Api::CudaDriver,
42                Source::Dlopen(LIB.to_string()),
43                Reason::NoDevice,
44            )];
45        }
46        (0..n).map(probe_device).collect()
47    }
48}
49
50#[allow(clippy::cast_possible_truncation, clippy::cast_possible_wrap)]
51fn probe_device(i: usize) -> BackendEntry {
52    let ctx = match CudaContext::new(i as i32) {
53        Ok(c) => c,
54        Err(e) => {
55            let mut entry = BackendEntry::unavailable(
56                BackendKind::Cuda,
57                Api::CudaDriver,
58                Source::Dlopen(LIB.to_string()),
59                Reason::ProbeFailed { error: format!("cuCtxCreate({i}): {e:?}") },
60            );
61            entry.device_index = Some(i as u32);
62            return entry;
63        }
64    };
65    let name = ctx.device_name().unwrap_or_else(|_| format!("cuda device {i}"));
66    let (free, total) =
67        ctx.memory_info().map(|(f, t)| (Some(f as u64), Some(t as u64))).unwrap_or((None, None));
68    let cc = ctx.compute_capability().ok().map(|(maj, min)| format!("sm_{maj}{min}"));
69    BackendEntry {
70        kind: BackendKind::Cuda,
71        api: Api::CudaDriver,
72        device_index: Some(i as u32),
73        device_uid: Some(super::device_uid("nvidia", &name)),
74        device_name: name,
75        vendor: "NVIDIA".to_string(),
76        vendor_id: Some(0x10de),
77        device_type: "discrete-gpu".to_string(),
78        mem_total: total,
79        mem_free: free,
80        mem_kind: MemKind::Discrete,
81        compute_class: cc,
82        caps: vec!["async".to_string()],
83        source: Source::Dlopen(LIB.to_string()),
84        status: Status::Ready,
85        transport: None,
86    }
87}
trueno/registry/cuda.rs

trueno/registry/
cuda.rs
