Add build.rs to avoid metal kernel jit compile overhead

candle-metal-kernels/build.rs

@@ -0,0 +1,61 @@
+use std::process::Command;
+use std::{env, str};
+use std::path::PathBuf;
+
+const METAL_SOURCES: [&str; 1] = ["reduce"];
+
+fn main() -> Result<(), String> {
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=*.metal");
+    println!("cargo:rerun-if-changed=*.m");
+
+    let xcrun_output = Command::new("xcrun")
+        .args(["--sdk", "macosx", "--show-sdk-path"])
+        .output()
+        .expect("xcrun command failed to start");
+
+    let sdk_path = str::from_utf8(&xcrun_output.stdout)
+        .expect("Invalid UTF-8 from xcrun")
+        .replace('\n', "");
+
+    println!("cargo:rerun-if-changed={sdk_path}");
+    let current_dir = env::current_dir().expect("Failed to get current directory");
+    let out_dir = PathBuf::from(std::env::var("OUT_DIR").map_err(|_|"OUT_DIR not set")?);
+
+    let sources = current_dir
+        .join("src")
+        .to_str()
+        .unwrap()
+        .to_string();
+
+    // Compile metal to air
+    let mut compile_air_cmd = Command::new("xcrun");
+    compile_air_cmd
+        .arg("metal")
+        .arg(format!("-working-directory={}", out_dir.to_str().ok_or("")?))
+        .arg("-c")
+        .arg("-frecord-sources")
+        .arg("-w");
+    for metal_file in METAL_SOURCES {
+        compile_air_cmd.arg(format!("{sources}/{metal_file}.metal"));
+    }
+    compile_air_cmd.spawn().expect("Failed to compile air");
+
+    // Compile air to metallib
+    let metallib = out_dir.join("candle.metallib");
+    let mut compile_metallib_cmd = Command::new("xcrun");
+    compile_metallib_cmd
+        .arg("metal")
+        .arg("-o")
+        .arg(&metallib);
+
+    for metal_file in METAL_SOURCES {
+        compile_metallib_cmd.arg(out_dir.join(format!("{metal_file}.air")));
+    }
+
+    compile_metallib_cmd
+        .spawn()
+        .expect("Failed to compile metallib");
+
+    Ok(())
+}

candle-metal-kernels/src/lib.rs

@@ -6,14 +6,14 @@ use std::collections::HashMap;
 use std::ffi::c_void;
 use std::sync::RwLock;
 
+const CANDLE: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/candle.metallib"));
 const AFFINE: &str = include_str!("affine.metal");
 const INDEXING: &str = include_str!("indexing.metal");
 const UNARY: &str = include_str!("unary.metal");
 const BINARY: &str = include_str!("binary.metal");
 const TERNARY: &str = include_str!("ternary.metal");
 const CAST: &str = include_str!("cast.metal");
 const CONV: &str = include_str!("conv.metal");
-const REDUCE: &str = include_str!("reduce.metal");
 const RANDOM: &str = include_str!("random.metal");
 const MFA: &[u8] = include_bytes!("libMetalFlashAttention.metallib");
 const QUANTIZED: &str = include_str!("quantized.metal");
@@ -114,13 +114,13 @@ macro_rules! set_params {
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum Source {
+    Candle,
     Affine,
     Indexing,
     Unary,
     Binary,
     Ternary,
     Cast,
-    Reduce,
     Mfa,
     Conv,
     Random,
@@ -243,11 +243,10 @@ impl Kernels {
             Source::Ternary => TERNARY,
             Source::Indexing => INDEXING,
             Source::Cast => CAST,
-            Source::Reduce => REDUCE,
             Source::Conv => CONV,
             Source::Random => RANDOM,
             Source::Quantized => QUANTIZED,
-            Source::Mfa => panic!("Invalid lib"),
+            _ => panic!("Invalid lib"),
         }
     }
 
@@ -263,6 +262,14 @@ impl Kernels {
             Ok(lib.clone())
         } else {
             let lib = match source {
+                Source::Candle => {
+                    let source_data = CANDLE;
+                    device.new_library_with_data(source_data).map_err(|e| {
+                        MetalKernelError::LoadLibraryError(format!(
+                            "Candle metal requires macosx > 13.0 or higher, cannot load mfa: {e}"
+                        ))
+                    })?
+                },
                 Source::Mfa => {
                     let source_data = MFA;
                     device.new_library_with_data(source_data).map_err(|e| {
@@ -569,7 +576,7 @@ pub fn call_reduce_contiguous(
     } else {
         (format!("{kernel_name}").leak(), 1)
     };
-    let pipeline = kernels.load_pipeline(device, Source::Reduce, name)?;
+    let pipeline = kernels.load_pipeline(device, Source::Candle, name)?;
 
     let encoder = command_buffer.new_compute_command_encoder();
     encoder.set_compute_pipeline_state(&pipeline);
@@ -628,7 +635,7 @@ pub fn call_reduce_strided(
 ) -> Result<(), MetalKernelError> {
     let length: usize = shape.iter().product();
     let work_per_threadgroup = length / out_length;
-    let pipeline = kernels.load_pipeline(device, Source::Reduce, kernel_name)?;
+    let pipeline = kernels.load_pipeline(device, Source::Candle, kernel_name)?;
 
     let encoder = command_buffer.new_compute_command_encoder();
     encoder.set_compute_pipeline_state(&pipeline);
@@ -697,7 +704,7 @@ pub fn call_last_softmax(
         (format!("{kernel_name}").leak(), 1)
     };
 
-    let pipeline = kernels.load_pipeline(device, Source::Reduce, name)?;
+    let pipeline = kernels.load_pipeline(device, Source::Candle, name)?;
     let encoder = command_buffer.new_compute_command_encoder();
     encoder.set_compute_pipeline_state(&pipeline);
 

candle-metal-kernels/src/reduce.metal

@@ -19,6 +19,8 @@ constexpr ushort granularity() {
 METAL_FUNC uint next_p2(uint x) {
     return 1 << (32 - clz(x - 1));
 }
+
+
 METAL_FUNC uint prev_p2(uint x) {
     return 1 << (31 - clz(x));
 }