Cycles: Enable inlining on Apple Silicon for 1.1x speedup

This is a stripped down version of D14645 without the scene specialisation optimisations.

The two major changes in this patch are:

- Enables more aggressive inlining on Apple Silicon resulting in a 1.1x speedup and 10% reduction in spill, at the cost of longer pipeline build times
- Revival of shader binary archives through a new ShaderCache which is shared between MetalDevice instances using the same physical MTLDevice. This mitigates the extra compile times via explicit caching (rather than, as before, relying on the implicit system shader cache which can be purged without notice)

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D14763

1 files changed, 27 insertions, 74 deletions

diff --git a/intern/cycles/device/metal/device_impl.mm b/intern/cycles/device/metal/device_impl.mm
index c01f51fb506..7d1212cb37c 100644
--- a/intern/cycles/device/metal/device_impl.mm
+++ b/intern/cycles/device/metal/device_impl.mm
@@ -275,96 +275,44 @@ bool MetalDevice::load_kernels(const uint _kernel_features)
    * active, but may still need to be rendered without motion blur if that isn't active as well. */
   motion_blur = kernel_features & KERNEL_FEATURE_OBJECT_MOTION;
 
-  NSError *error = NULL;
+  source[PSO_GENERIC] = get_source(kernel_features);
+  mtlLibrary[PSO_GENERIC] = compile(source[PSO_GENERIC]);
 
-  for (int i = 0; i < PSO_NUM; i++) {
-    if (mtlLibrary[i]) {
-      [mtlLibrary[i] release];
-      mtlLibrary[i] = nil;
-    }
-  }
+  MD5Hash md5;
+  md5.append(source[PSO_GENERIC]);
+  source_md5[PSO_GENERIC] = md5.get_hex();
+
+  metal_printf("Front-end compilation finished (generic)\n");
+
+  bool result = kernels.load(this, false);
 
+  reserve_local_memory(kernel_features);
+
+  return result;
+}
+
+id<MTLLibrary> MetalDevice::compile(string const &source)
+{
   MTLCompileOptions *options = [[MTLCompileOptions alloc] init];
 
   options.fastMathEnabled = YES;
   if (@available(macOS 12.0, *)) {
     options.languageVersion = MTLLanguageVersion2_4;
   }
-  else {
-    return false;
-  }
-
-  string metalsrc;
-
-  /* local helper: dump source to disk and return filepath */
-  auto dump_source = [&](int kernel_type) -> string {
-    string &source = source_used_for_compile[kernel_type];
-    string metalsrc = path_cache_get(path_join("kernels",
-                                               string_printf("%s.%s.metal",
-                                                             kernel_type_as_string(kernel_type),
-                                                             util_md5_string(source).c_str())));
-    path_write_text(metalsrc, source);
-    return metalsrc;
-  };
-
-  /* local helper: fetch the kernel source code, adjust it for specific PSO_.. kernel_type flavor,
-   * then compile it into a MTLLibrary */
-  auto fetch_and_compile_source = [&](int kernel_type) {
-    /* Record the source used to compile this library, for hash building later. */
-    string &source = source_used_for_compile[kernel_type];
-
-    switch (kernel_type) {
-      case PSO_GENERIC: {
-        source = get_source(kernel_features);
-        break;
-      }
-      case PSO_SPECIALISED: {
-        /* PSO_SPECIALISED derives from PSO_GENERIC */
-        string &generic_source = source_used_for_compile[PSO_GENERIC];
-        if (generic_source.empty()) {
-          generic_source = get_source(kernel_features);
-        }
-        source = "#define __KERNEL_METAL_USE_FUNCTION_SPECIALISATION__\n" + generic_source;
-        break;
-      }
-      default:
-        assert(0);
-    }
 
-    /* create MTLLibrary (front-end compilation) */
-    mtlLibrary[kernel_type] = [mtlDevice newLibraryWithSource:@(source.c_str())
+  NSError *error = NULL;
+  id<MTLLibrary> mtlLibrary = [mtlDevice newLibraryWithSource:@(source.c_str())
                                                       options:options
                                                         error:&error];
 
-    bool do_source_dump = (getenv("CYCLES_METAL_DUMP_SOURCE") != nullptr);
-
-    if (!mtlLibrary[kernel_type] || do_source_dump) {
-      string metalsrc = dump_source(kernel_type);
-
-      if (!mtlLibrary[kernel_type]) {
-        NSString *err = [error localizedDescription];
-        set_error(string_printf("Failed to compile library:\n%s", [err UTF8String]));
-
-        return false;
-      }
-    }
-    return true;
-  };
-
-  fetch_and_compile_source(PSO_GENERIC);
-
-  if (use_function_specialisation) {
-    fetch_and_compile_source(PSO_SPECIALISED);
+  if (!mtlLibrary) {
+    NSString *err = [error localizedDescription];
+    set_error(string_printf("Failed to compile library:\n%s", [err UTF8String]));
   }
 
-  metal_printf("Front-end compilation finished\n");
-
-  bool result = kernels.load(this, PSO_GENERIC);
-
   [options release];
-  reserve_local_memory(kernel_features);
 
-  return result;
+  return mtlLibrary;
 }
 
 void MetalDevice::reserve_local_memory(const uint kernel_features)
@@ -671,6 +619,11 @@ device_ptr MetalDevice::mem_alloc_sub_ptr(device_memory &mem, size_t offset, siz
   return 0;
 }
 
+const MetalKernelPipeline &MetalDevice::get_best_pipeline(DeviceKernel kernel) const
+{
+  return kernels.get_best_pipeline(this, kernel);
+}
+
 void MetalDevice::const_copy_to(const char *name, void *host, size_t size)
 {
   if (strcmp(name, "__data") == 0) {