More efficient cuda implementation for ConvTranspose1d. (#2211)

* More efficient cuda implementation for ConvTranspose1d.

* Small tweak.

candle-core/src/cpu_backend/mod.rs

@@ -10,7 +10,7 @@ pub use utils::{
 };
 
 const USE_IM2COL_CONV1D: bool = true;
-const USE_IM2COL_CONV1D_TR: bool = true;
+const USE_COL2IM_CONV1D_TR: bool = true;
 const USE_IM2COL_CONV2D: bool = true;
 
 // TODO: Maybe we should not implement [Clone] here and instead have an explicit allocator +
@@ -2249,7 +2249,7 @@ impl BackendStorage for CpuStorage {
             && params.dilation == 1
             && params.padding == 0
             && params.output_padding == 0;
-        if USE_IM2COL_CONV1D_TR && can_use_col2im {
+        if USE_COL2IM_CONV1D_TR && can_use_col2im {
             let (b_size, c_in, l_in) = l.shape().dims3()?;
             let (c_in2, c_out, k_size) = kernel_l.shape().dims3()?;
             if !kernel_l.is_contiguous() {

candle-core/src/cuda_backend/mod.rs

@@ -630,6 +630,31 @@ impl<'a> Map2 for Conv2D<'a> {
     }
 }
 
+struct Col2Im1D {
+    stride: usize,
+}
+
+impl Map1 for Col2Im1D {
+    fn f<T: DeviceRepr + WithDType + ValidAsZeroBits>(
+        &self,
+        col: &CudaSlice<T>,
+        dev: &CudaDevice,
+        l: &Layout,
+    ) -> Result<CudaSlice<T>> {
+        let (b_size, l_in, c_out, k_size) = l.shape().dims4()?;
+        let stride = self.stride;
+        let l_out = (l_in - 1) * stride + k_size;
+        let dst_el = b_size * c_out * l_out;
+        let mut im = unsafe { dev.alloc::<T>(dst_el) }.w()?;
+
+        let cfg = LaunchConfig::for_num_elems(dst_el as u32);
+        let params = (dst_el, l_out, l_in, c_out, k_size, stride, col, &mut im);
+        let func = dev.get_or_load_func(&kernel_name::<T>("col2im1d"), kernels::CONV)?;
+        unsafe { func.launch(cfg, params) }.w()?;
+        Ok(im)
+    }
+}
+
 struct ConvTranspose1D<'a>(&'a crate::conv::ParamsConvTranspose1D);
 impl<'a> Map2 for ConvTranspose1D<'a> {
     fn f<T: DeviceRepr + WithDType + ValidAsZeroBits>(
@@ -1366,9 +1391,55 @@ impl BackendStorage for CudaStorage {
         kernel_l: &Layout,
         params: &crate::conv::ParamsConvTranspose1D,
     ) -> Result<Self> {
+        const USE_COL2IM_CONV1D_TR: bool = true;
+
         let device = self.device().clone();
-        let slice =
-            ConvTranspose1D(params).map(&self.slice, l, &kernel.slice, kernel_l, &device)?;
+        let can_use_col2im = kernel_l.is_contiguous()
+            && params.dilation == 1
+            && params.padding == 0
+            && params.output_padding == 0;
+        let slice = if USE_COL2IM_CONV1D_TR && can_use_col2im {
+            let (b_size, c_in, l_in) = l.shape().dims3()?;
+            let (c_in2, c_out, k_size) = kernel_l.shape().dims3()?;
+            if !kernel_l.is_contiguous() {
+                crate::bail!(
+                    "convtr1d: the second argument (kernel) has to be contiguous {kernel_l:?}"
+                )
+            }
+            if c_in != c_in2 {
+                crate::bail!(
+                    "convtr1d: shape mismatch on c_in {:?} {:?}",
+                    l.shape(),
+                    kernel_l.shape()
+                )
+            }
+            let col = {
+                // This merges the last two dimensions of the kernel together.
+                let kernel_l_mm = Layout::new(
+                    (b_size, c_in, k_size * c_out).into(),
+                    vec![0, k_size * c_out, 1],
+                    kernel_l.start_offset(),
+                );
+                self.matmul(
+                    kernel,
+                    (
+                        b_size,
+                        /* m */ l_in,
+                        /* n */ c_out * k_size,
+                        /* k */ c_in,
+                    ),
+                    &l.transpose(1, 2)?,
+                    &kernel_l_mm,
+                )?
+            };
+            let col_l = Layout::contiguous((b_size, l_in, c_out, k_size));
+            Col2Im1D {
+                stride: params.stride,
+            }
+            .map(&col.slice, &device, &col_l)?
+        } else {
+            ConvTranspose1D(params).map(&self.slice, l, &kernel.slice, kernel_l, &device)?
+        };
         Ok(Self { slice, device })
     }
 

candle-kernels/src/conv.cu

@@ -97,6 +97,50 @@ __device__ void im2col1d(
   }
 }
 
+template <typename T>
+__device__ void col2im1d(
+    const size_t dst_el,
+    const size_t l_out,
+    const size_t l_in,
+    const size_t c_out,
+    const size_t k_size,
+    const size_t stride,
+    const T *src,
+    T *dst
+) {
+  const size_t dst_i = blockIdx.x * blockDim.x + threadIdx.x;
+  // src: (b_size, l_in, c_out, l_k)
+  // dst: (b_size, c_out, l_out)
+  if (dst_i >= dst_el) {
+    return;
+  }
+
+  const size_t dst_s0 = c_out * l_out;
+  const size_t dst_s1 = l_out;
+  const size_t src_s0 = c_out * k_size * l_in;
+  const size_t src_s1 = c_out * k_size;
+  const size_t src_s2 = k_size;
+
+  size_t tmp_dst_i = dst_i;
+  const size_t b_idx = tmp_dst_i / dst_s0;
+  tmp_dst_i -= b_idx * dst_s0;
+  const size_t c_idx = tmp_dst_i / dst_s1;
+  tmp_dst_i -= c_idx * dst_s1;
+  const int l_out_idx = tmp_dst_i;
+
+  dst[dst_i] = static_cast<T>(0);
+
+  int l_in_idx = l_out_idx / stride;
+  int k0 = l_out_idx - l_in_idx * stride;
+  // l_out_idx = l_in_idx * stride + k0
+  for (; k0 < k_size && l_in_idx >= 0; k0 += stride, --l_in_idx) {
+    if (l_in_idx < l_in) {
+      const size_t src_i = b_idx * src_s0 + l_in_idx * src_s1 + c_idx * src_s2 + k0;
+      dst[dst_i] += src[src_i];
+    }
+  }
+}
+
 template <typename T>
 __device__ void im2col(
     const size_t dst_numel,
@@ -542,6 +586,20 @@ extern "C" __global__ void FN_NAME(  \
   im2col1d<TYPENAME>(dst_numel, l_out, l_k, stride, padding, dilation, info, src, dst); \
 } \
 
+#define COL2IM1D_OP(TYPENAME, FN_NAME) \
+extern "C" __global__ void FN_NAME(  \
+    const size_t dst_el, \
+    const size_t l_out, \
+    const size_t l_in, \
+    const size_t c_out, \
+    const size_t k_size, \
+    const size_t stride, \
+    const TYPENAME *src, \
+    TYPENAME *dst \
+) {  \
+  col2im1d<TYPENAME>(dst_el, l_out, l_in, c_out, k_size, stride, src, dst); \
+} \
+
 #define IM2COL_OP(TYPENAME, FN_NAME) \
 extern "C" __global__ void FN_NAME(  \
     const size_t dst_numel, \
@@ -643,6 +701,7 @@ MAX_POOL2D_OP(__nv_bfloat16, max_pool2d_bf16)
 UPSAMPLE_NEAREST2D_OP(__nv_bfloat16, upsample_nearest2d_bf16)
 IM2COL_OP(__nv_bfloat16, im2col_bf16)
 IM2COL1D_OP(__nv_bfloat16, im2col1d_bf16)
+COL2IM1D_OP(__nv_bfloat16, col2im1d_bf16)
 #endif
 
 #if __CUDA_ARCH__ >= 530
@@ -655,6 +714,7 @@ MAX_POOL2D_OP(__half, max_pool2d_f16)
 UPSAMPLE_NEAREST2D_OP(__half, upsample_nearest2d_f16)
 IM2COL_OP(__half, im2col_f16)
 IM2COL1D_OP(__half, im2col1d_f16)
+COL2IM1D_OP(__half, col2im1d_f16)
 #endif
 
 CONV1D_OP(float, float, conv1d_f32)
@@ -701,3 +761,8 @@ IM2COL1D_OP(float, im2col1d_f32)
 IM2COL1D_OP(double, im2col1d_f64)
 IM2COL1D_OP(uint8_t, im2col1d_u8)
 IM2COL1D_OP(uint32_t, im2col1d_u32)
+
+COL2IM1D_OP(float, col2im1d_f32)
+COL2IM1D_OP(double, col2im1d_f64)
+COL2IM1D_OP(uint8_t, col2im1d_u8)
+COL2IM1D_OP(uint32_t, col2im1d_u32)