Use the new MLX kernels to handle the BF16 matmul. (huggingface#2470)

JySongWithZhangCe · Sep 11, 2024 · afb6575 · afb6575
1 parent 5635650
commit afb6575
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Showing 2 changed files with 46 additions and 26 deletions.
diff --git a/candle-core/src/device.rs b/candle-core/src/device.rs
@@ -173,8 +173,8 @@ impl Device {
 
     pub fn supports_bf16(&self) -> bool {
         match self {
-            Self::Cuda(_) => true,
-            Self::Metal(_) | Self::Cpu => false,
+            Self::Cuda(_) | Self::Metal(_) => true,
+            Self::Cpu => false,
         }
     }
 

diff --git a/candle-core/src/metal_backend/mod.rs b/candle-core/src/metal_backend/mod.rs
@@ -1398,6 +1398,7 @@ impl BackendStorage for MetalStorage {
         .map_err(MetalError::from)?;
         Ok(acc)
     }
+
     fn matmul(
         &self,
         rhs: &Self,
@@ -1406,32 +1407,51 @@ impl BackendStorage for MetalStorage {
         rhs_l: &Layout,
     ) -> Result<Self> {
         let buffer = self.device.new_buffer(b * m * n, self.dtype, "matmul")?;
-        let name = match self.dtype {
-            DType::F32 => "sgemm",
-            DType::F16 => "hgemm",
-            DType::BF16 => "bgemm",
-            dtype => {
-                return Err(MetalError::Message(format!("matmul doesn't support {dtype:?}")).into())
-            }
-        };
-
         let command_buffer = self.device.command_buffer()?;
         command_buffer.set_label("matmul");
-        candle_metal_kernels::call_gemm(
-            &self.device.device,
-            &command_buffer,
-            &self.device.kernels,
-            name,
-            (b, m, n, k),
-            lhs_l.stride(),
-            lhs_l.start_offset() * self.dtype.size_in_bytes(),
-            &self.buffer,
-            rhs_l.stride(),
-            rhs_l.start_offset() * rhs.dtype.size_in_bytes(),
-            &rhs.buffer,
-            &buffer,
-        )
-        .map_err(MetalError::from)?;
+        if self.dtype == DType::BF16 {
+            candle_metal_kernels::call_mlx_gemm(
+                &self.device.device,
+                &command_buffer,
+                &self.device.kernels,
+                candle_metal_kernels::GemmDType::BF16,
+                (b, m, n, k),
+                lhs_l.stride(),
+                lhs_l.start_offset() * self.dtype.size_in_bytes(),
+                &self.buffer,
+                rhs_l.stride(),
+                rhs_l.start_offset() * rhs.dtype.size_in_bytes(),
+                &rhs.buffer,
+                &buffer,
+            )
+            .map_err(MetalError::from)?;
+        } else {
+            let name = match self.dtype {
+                DType::F32 => "sgemm",
+                DType::F16 => "hgemm",
+                dtype => {
+                    return Err(
+                        MetalError::Message(format!("matmul doesn't support {dtype:?}")).into(),
+                    )
+                }
+            };
+
+            candle_metal_kernels::call_gemm(
+                &self.device.device,
+                &command_buffer,
+                &self.device.kernels,
+                name,
+                (b, m, n, k),
+                lhs_l.stride(),
+                lhs_l.start_offset() * self.dtype.size_in_bytes(),
+                &self.buffer,
+                rhs_l.stride(),
+                rhs_l.start_offset() * rhs.dtype.size_in_bytes(),
+                &rhs.buffer,
+                &buffer,
+            )
+            .map_err(MetalError::from)?;
+        }
         Ok(Self::new(
             buffer,
             self.device.clone(),