[wasm] Disable interp pgo recording by default since it adds startup overhead (dotnet#101566)

* Disable interp pgo recording by default since it adds startup overhead
* Make withRuntimeOptions not trample existing runtime options

Author: kg

src/mono/browser/runtime/loader/run.ts

@@ -158,6 +158,10 @@ export class HostBuilder implements DotnetHostBuilder {
                 interpreterPgo: value,
                 interpreterPgoSaveDelay: autoSaveDelay
             });
+            if (monoConfig.runtimeOptions)
+                monoConfig.runtimeOptions.push("--interp-pgo-recording");
+            else
+                monoConfig.runtimeOptions = ["--interp-pgo-recording"];
             return this;
         } catch (err) {
             mono_exit(1, err);
@@ -268,9 +272,10 @@ export class HostBuilder implements DotnetHostBuilder {
     withRuntimeOptions (runtimeOptions: string[]): DotnetHostBuilder {
         try {
             mono_assert(runtimeOptions && Array.isArray(runtimeOptions), "must be array of strings");
-            deep_merge_config(monoConfig, {
-                runtimeOptions
-            });
+            if (monoConfig.runtimeOptions)
+                monoConfig.runtimeOptions.push(...runtimeOptions);
+            else
+                monoConfig.runtimeOptions = runtimeOptions;
             return this;
         } catch (err) {
             mono_exit(1, err);

src/mono/mono/utils/options-def.h

@@ -61,7 +61,7 @@ DEFINE_BOOL(wasm_exceptions, "wasm-exceptions", FALSE, "Enable codegen for WASM
 DEFINE_BOOL(aot_lazy_assembly_load, "aot-lazy-assembly-load", FALSE, "Load assemblies referenced by AOT images lazily")
 
 #if HOST_BROWSER
-DEFINE_BOOL(interp_pgo_recording, "interp-pgo-recording", TRUE, "Record interpreter tiering information for automatic PGO")
+DEFINE_BOOL(interp_pgo_recording, "interp-pgo-recording", FALSE, "Record interpreter tiering information for automatic PGO")
 #else
 DEFINE_BOOL(interp_pgo_recording, "interp-pgo-recording", FALSE, "Record interpreter tiering information for automatic PGO")
 DEFINE_BOOL(wasm_gc_safepoints, "wasm-gc-safepoints", FALSE, "Use GC safepoints on WASM")

src/mono/sample/wasm/browser-bench/main.js

@@ -225,11 +225,6 @@ try {
         //  console to see statistics on how much code it generated and whether any new opcodes
         //  are causing traces to fail to compile
         .withRuntimeOptions(["--jiterpreter-stats-enabled"])
-        // We enable interpreter PGO so that you can exercise it in local tests, i.e.
-        //  run browser-bench one, then refresh the tab to measure the performance improvement
-        //  on the second run of browser-bench. The overall speed of the benchmarks won't
-        //  improve much, but the time spent generating code during the run will go down
-        .withInterpreterPgo(true, 30)
         .withElementOnExit()
         .withExitCodeLogging()
         .create();

src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/main.js

@@ -37,7 +37,7 @@ switch (testCase) {
             let alreadyFailed = [];
             dotnet.withDiagnosticTracing(true).withResourceLoader((type, name, defaultUri, integrity, behavior) => {
                 if (type === "dotnetjs") {
-                    // loadBootResource could return string with unqualified name of resource. 
+                    // loadBootResource could return string with unqualified name of resource.
                     // It assumes that we resolve it with document.baseURI
                     // we test it here
                     return `_framework/${name}`;
@@ -131,8 +131,8 @@ try {
                 }
             });
             const iterationCount = params.get("iterationCount") ?? 70;
-            for (let i = 0; i < iterationCount; i++) { 
-                exports.InterpPgoTest.Greeting(); 
+            for (let i = 0; i < iterationCount; i++) {
+                exports.InterpPgoTest.Greeting();
             };
             await INTERNAL.interp_pgo_save_data();
             exit(0);