Don't cache; separate from interpreter; use /sys/module/nvidia/version

Author: charliermarsh

Cargo.lock

@@ -1259,7 +1259,7 @@ pub struct PipCompileArgs {
     #[arg(long, overrides_with("emit_index_annotation"), hide = true)]
     pub no_emit_index_annotation: bool,
 
-    /// The backend to use when fetching packages in the `PyTorch` ecosystem (e.g., `cu126` or `auto`)
+    /// The backend to use when fetching packages in the `PyTorch` ecosystem (e.g., `cpu`, `cu126`, or `auto`).
     ///
     /// When set, uv will ignore the configured index URLs for packages in the `PyTorch` ecosystem,
     /// and will instead use the defined backend.
@@ -1269,7 +1269,7 @@ pub struct PipCompileArgs {
     ///
     /// The `auto` mode will attempt to detect the appropriate `PyTorch` index based on the currently
     /// installed CUDA drivers.
-    #[arg(long, value_enum)]
+    #[arg(long, value_enum, env = EnvVars::UV_TORCH_BACKEND)]
     pub torch_backend: Option<TorchMode>,
 
     #[command(flatten)]
@@ -1513,7 +1513,7 @@ pub struct PipSyncArgs {
     #[arg(long)]
     pub dry_run: bool,
 
-    /// The backend to use when fetching packages in the `PyTorch` ecosystem (e.g., `cu126` or `auto`)
+    /// The backend to use when fetching packages in the `PyTorch` ecosystem (e.g., `cpu`, `cu126`, or `auto`).
     ///
     /// When set, uv will ignore the configured index URLs for packages in the `PyTorch` ecosystem,
     /// and will instead use the defined backend.
@@ -1523,7 +1523,7 @@ pub struct PipSyncArgs {
     ///
     /// The `auto` mode will attempt to detect the appropriate `PyTorch` index based on the currently
     /// installed CUDA drivers.
-    #[arg(long, value_enum)]
+    #[arg(long, value_enum, env = EnvVars::UV_TORCH_BACKEND)]
     pub torch_backend: Option<TorchMode>,
 
     #[command(flatten)]
@@ -1818,7 +1818,7 @@ pub struct PipInstallArgs {
     #[arg(long)]
     pub dry_run: bool,
 
-    /// The backend to use when fetching packages in the `PyTorch` ecosystem (e.g., `cu126` or `auto`)
+    /// The backend to use when fetching packages in the `PyTorch` ecosystem (e.g., `cpu`, `cu126`, or `auto`)
     ///
     /// When set, uv will ignore the configured index URLs for packages in the `PyTorch` ecosystem,
     /// and will instead use the defined backend.
@@ -1828,7 +1828,7 @@ pub struct PipInstallArgs {
     ///
     /// The `auto` mode will attempt to detect the appropriate `PyTorch` index based on the currently
     /// installed CUDA drivers.
-    #[arg(long, value_enum)]
+    #[arg(long, value_enum, env = EnvVars::UV_TORCH_BACKEND)]
     pub torch_backend: Option<TorchMode>,
 
     #[command(flatten)]

crates/uv-cli/src/lib.rs

@@ -16,7 +16,6 @@ doctest = false
 workspace = true
 
 [dependencies]
-uv-pep440 = { workspace = true }
 uv-small-str = { workspace = true }
 
 memchr = { workspace = true }

crates/uv-platform-tags/Cargo.toml

@@ -1,12 +1,10 @@
 pub use abi_tag::{AbiTag, ParseAbiTagError};
-pub use accelerator::Accelerator;
 pub use language_tag::{LanguageTag, ParseLanguageTagError};
 pub use platform::{Arch, Os, Platform, PlatformError};
 pub use platform_tag::{ParsePlatformTagError, PlatformTag};
 pub use tags::{BinaryFormat, IncompatibleTag, TagCompatibility, TagPriority, Tags, TagsError};
 
 mod abi_tag;
-mod accelerator;
 mod language_tag;
 mod platform;
 mod platform_tag;

crates/uv-platform-tags/src/accelerator.rs

@@ -405,47 +405,6 @@ def get_distutils_scheme():
         return get_distutils_scheme()
 
 
-def _detect_cuda_driver_version():
-    """Detect the installed CUDA Driver version.
-
-    Reads from the `UV_CUDA_DRIVER_VERSION` environment variable, if set; otherwise,
-    queries `nvidia-smi` for the driver version.
-    """
-    driver_version = os.getenv("UV_CUDA_DRIVER_VERSION")
-    if driver_version is not None:
-        return driver_version
-
-    import subprocess
-
-    try:
-        result = subprocess.run(
-            [
-                "nvidia-smi",
-                "--query-gpu=driver_version",
-                "--format=csv",
-            ],
-            check=True,
-            capture_output=True,
-            text=True,
-        )
-        return result.stdout.splitlines()[-1]
-    except (FileNotFoundError, subprocess.CalledProcessError):
-        return None
-
-
-def get_accelerator():
-    cuda_driver_version = _detect_cuda_driver_version()
-    if cuda_driver_version is None:
-        accelerator = None
-    else:
-        accelerator = {
-            "name": "cuda",
-            "driver_version": cuda_driver_version,
-        }
-
-    return accelerator
-
-
 def get_operating_system_and_architecture():
     """Determine the Python interpreter architecture and operating system.
 
@@ -574,7 +533,6 @@ def get_operating_system_and_architecture():
             )
         )
         sys.exit(0)
-
     return {"os": operating_system, "arch": architecture}
 
 
@@ -593,21 +551,21 @@ def main() -> None:
         "sys_platform": sys.platform,
     }
 
-    os_arch = get_operating_system_and_architecture()
-    accelerator = get_accelerator()
+    os_and_arch = get_operating_system_and_architecture()
 
     manylinux_compatible = False
 
-    if os_arch["os"]["name"] == "manylinux":
+    if os_and_arch["os"]["name"] == "manylinux":
         # noinspection PyProtectedMember
         from .packaging._manylinux import _get_glibc_version, _is_compatible
 
         manylinux_compatible = _is_compatible(
-            arch=os_arch["arch"], version=_get_glibc_version()
+            arch=os_and_arch["arch"], version=_get_glibc_version()
         )
-    elif os_arch["os"]["name"] == "musllinux":
+    elif os_and_arch["os"]["name"] == "musllinux":
         manylinux_compatible = True
 
+
     # By default, pip uses sysconfig on Python 3.10+.
     # But Python distributors can override this decision by setting:
     #     sysconfig._PIP_USE_SYSCONFIG = True / False
@@ -665,14 +623,10 @@ def main() -> None:
         # Prior to the introduction of `sysconfig` patching, python-build-standalone installations would always use
         # "/install" as the prefix. With `sysconfig` patching, we rewrite the prefix to match the actual installation
         # location. So in newer versions, we also write a dedicated flag to indicate standalone builds.
-        "standalone": (
-            sysconfig.get_config_var("prefix") == "/install"
-            or bool(sysconfig.get_config_var("PYTHON_BUILD_STANDALONE"))
-        ),
+        "standalone": sysconfig.get_config_var("prefix") == "/install" or bool(sysconfig.get_config_var("PYTHON_BUILD_STANDALONE")),
         "scheme": get_scheme(use_sysconfig_scheme),
         "virtualenv": get_virtualenv(),
-        "platform": os_arch,
-        "accelerator": accelerator,
+        "platform": os_and_arch,
         "manylinux_compatible": manylinux_compatible,
         # The `t` abiflag for freethreading Python.
         # https://peps.python.org/pep-0703/#build-configuration-changes

crates/uv-platform-tags/src/lib.rs

@@ -21,7 +21,7 @@ use uv_fs::{write_atomic_sync, PythonExt, Simplified};
 use uv_install_wheel::Layout;
 use uv_pep440::Version;
 use uv_pep508::{MarkerEnvironment, StringVersion};
-use uv_platform_tags::{Accelerator, Platform};
+use uv_platform_tags::Platform;
 use uv_platform_tags::{Tags, TagsError};
 use uv_pypi_types::{ResolverMarkerEnvironment, Scheme};
 
@@ -53,7 +53,6 @@ pub struct Interpreter {
     target: Option<Target>,
     prefix: Option<Prefix>,
     pointer_size: PointerSize,
-    accelerator: Option<Accelerator>,
     gil_disabled: bool,
 }
 
@@ -77,7 +76,6 @@ impl Interpreter {
             sys_prefix: info.sys_prefix,
             sys_base_exec_prefix: info.sys_base_exec_prefix,
             pointer_size: info.pointer_size,
-            accelerator: info.accelerator,
             gil_disabled: info.gil_disabled,
             sys_base_prefix: info.sys_base_prefix,
             sys_base_executable: info.sys_base_executable,
@@ -174,18 +172,12 @@ impl Interpreter {
         Ok(base_python)
     }
 
-    /// Returns the [`Platform`] for this Python executable.
+    /// Returns the path to the Python virtual environment.
     #[inline]
     pub fn platform(&self) -> &Platform {
         &self.platform
     }
 
-    /// Returns the [`Accelerator`] for this Python executable.
-    #[inline]
-    pub fn accelerator(&self) -> Option<&Accelerator> {
-        self.accelerator.as_ref()
-    }
-
     /// Returns the [`MarkerEnvironment`] for this Python executable.
     #[inline]
     pub const fn markers(&self) -> &MarkerEnvironment {
@@ -737,7 +729,6 @@ struct InterpreterInfo {
     stdlib: PathBuf,
     standalone: bool,
     pointer_size: PointerSize,
-    accelerator: Option<Accelerator>,
     gil_disabled: bool,
 }
 

crates/uv-python/python/get_interpreter_info.py

@@ -3,7 +3,6 @@ use std::path::PathBuf;
 
 use url::Url;
 
-use crate::{FilesystemOptions, Options, PipOptions};
 use uv_configuration::{
     ConfigSettings, IndexStrategy, KeyringProviderType, RequiredVersion, TargetTriple,
     TrustedPublishing,
@@ -15,6 +14,8 @@ use uv_python::{PythonDownloads, PythonPreference, PythonVersion};
 use uv_resolver::{AnnotationStyle, ExcludeNewer, ForkStrategy, PrereleaseMode, ResolutionMode};
 use uv_torch::TorchMode;
 
+use crate::{FilesystemOptions, Options, PipOptions};
+
 pub trait Combine {
     /// Combine two values, preferring the values in `self`.
     ///

crates/uv-python/src/interpreter.rs

@@ -673,4 +673,11 @@ impl EnvVars {
     ///
     /// This is a quasi-standard variable, described, e.g., in `ncurses(3x)`.
     pub const COLUMNS: &'static str = "COLUMNS";
+
+    /// The CUDA driver version to assume when inferring the PyTorch backend.
+    #[attr_hidden]
+    pub const UV_CUDA_DRIVER_VERSION: &'static str = "UV_CUDA_DRIVER_VERSION";
+
+    /// Equivalent to the `--torch-backend` command-line argument (e.g., `cpu`, `cu126`, or `auto`).
+    pub const UV_TORCH_BACKEND: &'static str = "UV_TORCH_BACKEND";
 }

crates/uv-settings/src/combine.rs

@@ -14,11 +14,15 @@ uv-distribution-types = { workspace = true }
 uv-normalize = { workspace = true }
 uv-pep440 = { workspace = true }
 uv-platform-tags = { workspace = true }
+uv-static = { workspace = true }
 
 clap = { workspace = true, optional = true }
 either = { workspace = true }
+fs-err = { workspace = true }
 schemars = { workspace = true, optional = true }
 serde = { workspace = true }
+thiserror = { workspace = true }
+tracing = { workspace = true }
 
 [lints]
 workspace = true