Support for UG kernels. (#2579)

* Support for UG kernels.

* Add a dedicated test.

candle-core/src/cuda_backend/device.rs

@@ -51,6 +51,27 @@ impl CudaDevice {
         self.device.clone()
     }
 
+    pub fn compile(
+        &self,
+        func_name: &'static str,
+        kernel: ug::lang::ssa::Kernel,
+    ) -> Result<CudaFunction> {
+        let mut buf = vec![];
+        ug_cuda::code_gen::gen(&mut buf, func_name, &kernel)?;
+        let cuda_code = String::from_utf8(buf)?;
+        let opts = cudarc::nvrtc::CompileOptions {
+            use_fast_math: Some(true),
+            ..Default::default()
+        };
+        let ptx = cudarc::nvrtc::safe::compile_ptx_with_opts(cuda_code, opts).w()?;
+        self.device.load_ptx(ptx, "ug", &[func_name]).w()?;
+        let func = match self.device.get_func("ug", func_name) {
+            Some(func) => func,
+            None => crate::bail!("unknown function ug::{func_name}"),
+        };
+        Ok(func)
+    }
+
     pub fn id(&self) -> DeviceId {
         self.id
     }

candle-core/src/custom_op.rs

@@ -375,3 +375,70 @@ impl Tensor {
         )
     }
 }
+
+pub struct UgIOp1 {
+    name: &'static str,
+    #[cfg(feature = "cuda")]
+    func: cudarc::driver::CudaFunction,
+}
+
+impl UgIOp1 {
+    #[allow(unused)]
+    pub fn new(
+        name: &'static str,
+        kernel: ug::lang::ssa::Kernel,
+        device: &crate::Device,
+    ) -> Result<Self> {
+        #[cfg(feature = "cuda")]
+        {
+            let device = device.as_cuda_device()?;
+            let func = device.compile(name, kernel)?;
+            Ok(Self { name, func })
+        }
+        #[cfg(not(feature = "cuda"))]
+        {
+            Ok(Self { name })
+        }
+    }
+}
+
+impl InplaceOp1 for UgIOp1 {
+    fn name(&self) -> &'static str {
+        self.name
+    }
+
+    fn cpu_fwd(&self, _: &mut CpuStorage, _: &Layout) -> Result<()> {
+        crate::bail!("ug ops are only supported on cuda at the moment")
+    }
+
+    fn metal_fwd(&self, _: &mut MetalStorage, _: &Layout) -> Result<()> {
+        crate::bail!("ug ops are only supported on cuda at the moment")
+    }
+
+    #[cfg(feature = "cuda")]
+    fn cuda_fwd(&self, sto: &mut CudaStorage, layout: &Layout) -> Result<()> {
+        use crate::cuda_backend::WrapErr;
+        use cudarc::driver::LaunchAsync;
+
+        let elem_count = layout.shape().elem_count();
+        // TODO: support more dtypes.
+        let sto = sto.as_cuda_slice::<f32>()?;
+        let sto = match layout.contiguous_offsets() {
+            None => crate::bail!("input has to be contiguous"),
+            Some((o1, o2)) => sto.slice(o1..o2),
+        };
+        let params = (&sto,);
+        let (g, b) = if elem_count % 32 == 0 {
+            (elem_count / 32, 32)
+        } else {
+            (elem_count, 1)
+        };
+        let cfg = cudarc::driver::LaunchConfig {
+            grid_dim: (g as u32, 1, 1),
+            block_dim: (b as u32, 1, 1),
+            shared_mem_bytes: 0,
+        };
+        unsafe { self.func.clone().launch(cfg, params) }.w()?;
+        Ok(())
+    }
+}

candle-core/src/device.rs

@@ -130,6 +130,14 @@ impl Device {
         Ok(Self::Cuda(crate::CudaDevice::new(ordinal)?))
     }
 
+    pub fn as_cuda_device(&self) -> Result<&crate::CudaDevice> {
+        match self {
+            Self::Cuda(d) => Ok(d),
+            Self::Cpu => crate::bail!("expected a cuda device, got cpu"),
+            Self::Metal(_) => crate::bail!("expected a cuda device, got Metal"),
+        }
+    }
+
     pub fn new_cuda_with_stream(ordinal: usize) -> Result<Self> {
         Ok(Self::Cuda(crate::CudaDevice::new_with_stream(ordinal)?))
     }

candle-core/src/error.rs

@@ -165,6 +165,9 @@ pub enum Error {
     #[error("Metal error {0}")]
     Metal(#[from] MetalError),
 
+    #[error(transparent)]
+    Ug(#[from] ug::Error),
+
     #[error(transparent)]
     TryFromIntError(#[from] core::num::TryFromIntError),
 
@@ -179,6 +182,10 @@ pub enum Error {
     #[error(transparent)]
     ParseInt(#[from] std::num::ParseIntError),
 
+    /// Utf8 parse error.
+    #[error(transparent)]
+    FromUtf8(#[from] std::string::FromUtf8Error),
+
     /// I/O error.
     #[error(transparent)]
     Io(#[from] std::io::Error),

candle-core/src/lib.rs

@@ -77,7 +77,7 @@ mod variable;
 pub use cuda_backend::cudnn;
 
 pub use cpu_backend::{CpuStorage, CpuStorageRef};
-pub use custom_op::{CustomOp1, CustomOp2, CustomOp3, InplaceOp1, InplaceOp2, InplaceOp3};
+pub use custom_op::{CustomOp1, CustomOp2, CustomOp3, InplaceOp1, InplaceOp2, InplaceOp3, UgIOp1};
 pub use device::{Device, DeviceLocation, NdArray};
 pub use dtype::{DType, DTypeParseError, FloatDType, IntDType, WithDType};
 pub use error::{Error, Result};