whisper.swiftui : add model download list & bench methods (#2546)

* swift : fix resources & exclude build

* whisper : impl whisper_timings struct & api

* whisper.swiftui : model list & bench methods

* whisper : return ptr for whisper_get_timings

* revert unnecessary change

* whisper : avoid designated initializer

* whisper.swiftui: code style changes

* whisper.swiftui : get device name / os from UIDevice

* whisper.swiftui : fix UIDevice usage

* whisper.swiftui : add memcpy and ggml_mul_mat (commented)

examples/whisper.swiftui/whisper.cpp.swift/LibWhisper.swift

@@ -1,4 +1,5 @@
 import Foundation
+import UIKit
 import whisper
 
 enum WhisperError: Error {
@@ -55,11 +56,93 @@ actor WhisperContext {
         return transcription
     }
 
+    static func benchMemcpy(nThreads: Int32) async -> String {
+        return String.init(cString: whisper_bench_memcpy_str(nThreads))
+    }
+
+    static func benchGgmlMulMat(nThreads: Int32) async -> String {
+        return String.init(cString: whisper_bench_ggml_mul_mat_str(nThreads))
+    }
+
+    private func systemInfo() -> String {
+        var info = ""
+        if (ggml_cpu_has_neon() != 0) { info += "NEON " }
+        if (ggml_cpu_has_metal() != 0) { info += "METAL " }
+        if (ggml_cpu_has_blas() != 0) { info += "BLAS " }
+        return String(info.dropLast())
+    }
+
+    func benchFull(modelName: String, nThreads: Int32) async -> String {
+        let nMels = whisper_model_n_mels(context)
+        if (whisper_set_mel(context, nil, 0, nMels) != 0) {
+            return "error: failed to set mel"
+        }
+        
+        // heat encoder
+        if (whisper_encode(context, 0, nThreads) != 0) {
+            return "error: failed to encode"
+        }
+        
+        var tokens = [whisper_token](repeating: 0, count: 512)
+        
+        // prompt heat
+        if (whisper_decode(context, &tokens, 256, 0, nThreads) != 0) {
+            return "error: failed to decode"
+        }
+        
+        // text-generation heat
+        if (whisper_decode(context, &tokens, 1, 256, nThreads) != 0) {
+            return "error: failed to decode"
+        }
+        
+        whisper_reset_timings(context)
+        
+        // actual run
+        if (whisper_encode(context, 0, nThreads) != 0) {
+            return "error: failed to encode"
+        }
+        
+        // text-generation
+        for i in 0..<256 {
+            if (whisper_decode(context, &tokens, 1, Int32(i), nThreads) != 0) {
+                return "error: failed to decode"
+            }
+        }
+        
+        // batched decoding
+        for _ in 0..<64 {
+            if (whisper_decode(context, &tokens, 5, 0, nThreads) != 0) {
+                return "error: failed to decode"
+            }
+        }
+        
+        // prompt processing
+        for _ in 0..<16 {
+            if (whisper_decode(context, &tokens, 256, 0, nThreads) != 0) {
+                return "error: failed to decode"
+            }
+        }
+
+        whisper_print_timings(context)
+
+        let deviceModel = await UIDevice.current.model
+        let systemName = await UIDevice.current.systemName
+        let systemInfo = self.systemInfo()
+        let timings: whisper_timings = whisper_get_timings(context).pointee
+        let encodeMs = String(format: "%.2f", timings.encode_ms)
+        let decodeMs = String(format: "%.2f", timings.decode_ms)
+        let batchdMs = String(format: "%.2f", timings.batchd_ms)
+        let promptMs = String(format: "%.2f", timings.prompt_ms)
+        return "| \(deviceModel) | \(systemName) | \(systemInfo) | \(modelName) | \(nThreads) | 1 | \(encodeMs) | \(decodeMs) | \(batchdMs) | \(promptMs) | <todo> |"
+    }
+
     static func createContext(path: String) throws -> WhisperContext {
         var params = whisper_context_default_params()
 #if targetEnvironment(simulator)
         params.use_gpu = false
         print("Running on the simulator, using CPU")
+#else
+        params.flash_attn = true // Enabled by default for Metal
 #endif
         let context = whisper_init_from_file_with_params(path, params)
         if let context {