Cache immutable Wasm server configuration encoding

docs/wasm-runtime-architecture.md

@@ -87,9 +87,11 @@ the boundary).
   children yielding `const DValue&`.
 - The request context (`params`/`get`/`post`/`cookies`/`session`, the raw body
   `in`, and—for WS—the connection context) is marshalled into a single `ctx`
-  DValue, UCEB-encoded, and handed to the workspace. The response (body,
+  DValue and UCEB-encoded. Immutable server configuration is UCEB-encoded once
-  headers, status, and any `meta` such as `ws_commands`) comes back the same
+  per worker as a flat string map; both byte ranges are written into one guest
-  way.
+  buffer. The guest decodes the flat map directly into its fresh `Server` and
+  the dynamic tree into its fresh `Request`. The response (body, headers,
+  status, and any `meta` such as `ws_commands`) comes back as UCEB.
 
 See [`docs/wasm-phase1-dvalue-abi.md`](wasm-phase1-dvalue-abi.md) for the wire
 format details.
@@ -160,10 +162,11 @@ drops one empty workspace. This preserves Wasmtime's fork boundary while
 preventing the first request assigned to each worker from paying engine, linker,
 or pre-instantiation startup.
 Server configuration is immutable by that point. The worker therefore retains
-one native `DValue` view of it; each request's temporary context tree references
+one native `DValue` view and one UCEB encoding of it. Each request transfers
-that view while UCEB is encoded, avoiding a repeated native tree copy. The guest
+those cached bytes and the guest decodes the flat scalar map directly into its
-still decodes the bytes into its fresh request tree. Request parameters, body,
+fresh `Server`, avoiding both repeated native encoding and an intermediate guest
-cookies, session, call data, and response state are never retained this way.
+`DValue` tree. Request parameters, body, cookies, session, call data, and
+response state are never retained this way.
 Startup duration or failure is written to the service log. The serialized core
 module lives in the configured writable cache root rather than beside the
 possibly root-owned deployed `core.wasm`; freshness still uses the deployed
@@ -285,7 +288,8 @@ request rather than being deep-copied twice; the historical by-value
 artifacts stay ABI-compatible. `request_perf()` subdivides birth into policy,
 import materialization, core instantiation, export/table lookup, and initialization,
 and context transfer into bytes, host encode, guest allocation/write,
-guest decode/application, and free.
+guest decode/application, and free. The byte profile separately reports the
+worker-cached server-configuration portion.
 
 ### Task callbacks and workspace lifetime
 

site/tests/core.uce

@@ -51,6 +51,7 @@ RENDER(Request& context)
 	check("str_ends_with()", str_ends_with("component.uce", ".uce"), "component.uce ends with .uce");
 	check("to_lower() / to_upper()", to_lower("MiXeD") == "mixed" && to_upper("MiXeD") == "MIXED", to_lower("MiXeD") + " / " + to_upper("MiXeD"));
 	check("request context params", context.params["SCRIPT_URL"] != "" && context.params["BASE_URL"] != "" && context.params["ROUTE_PATH"] != "" && context.params["ROUTE_PAGE"] != "" && context.params["ROUTE_VALID"] == "1", "script=" + context.params["SCRIPT_URL"] + " base=" + context.params["BASE_URL"] + " route=" + context.params["ROUTE_PATH"] + " page=" + context.params["ROUTE_PAGE"] + " valid=" + context.params["ROUTE_VALID"]);
+	check("request server configuration", context.server && context.server->config["BIN_DIRECTORY"] != "" && context.server->config["SITE_DIRECTORY"] != "" && context.server->config["SESSION_PATH"] != "" && context.server->config["WASM_CORE_PATH"] != "", "bin=" + context.server->config["BIN_DIRECTORY"] + " site=" + context.server->config["SITE_DIRECTORY"] + " session=" + context.server->config["SESSION_PATH"] + " core=" + context.server->config["WASM_CORE_PATH"]);
 	String saved_query_string = context.params["QUERY_STRING"];
 	context.params["QUERY_STRING"] = "workspace/projects&theme=dark";
 	check("request_query_path() delegates to request_query_route()", request_query_path(context) == request_query_route(context)["l_path"].to_string() && request_query_path(context) == "workspace/projects", request_query_path(context) + " / " + json_encode(request_query_route(context)));

src/lib/dvalue.cpp

@@ -1175,6 +1175,87 @@ bool ucb_decode(const String& encoded, DValue& out, String* error_out)
 	return(false);
 }
 
+#ifdef __UCE_WASM_CORE__
+static bool ucb_decode_flat_string_map(const String& encoded, StringMap& out, String* error_out)
+{
+	String error;
+	StringMap decoded;
+	size_t offset = 0;
+	auto fail = [&](String message) {
+		error = message;
+		return(false);
+	};
+	if(encoded.size() < 5 || encoded.compare(0, 4, UCEB_MAGIC) != 0)
+		fail("missing UCEB magic header");
+	else if((u8)encoded[4] != UCEB_VERSION)
+		fail("unsupported UCEB version");
+	else
+	{
+		offset = 5;
+		if(encoded.size() - offset < 2)
+			fail("unexpected end of UCEB2 string map");
+		else
+		{
+			u8 flags = (u8)encoded[offset++];
+			char type = encoded[offset++];
+			u64 scalar_len = 0, child_count = 0;
+			if(flags != 0 || type != 'M')
+				fail("UCEB2 string map root must be a map");
+			else if(!ucb_read_varint(encoded, offset, scalar_len) || scalar_len != 0)
+				fail("UCEB2 string map root must have no scalar");
+			else if(!ucb_read_varint(encoded, offset, child_count))
+				fail("invalid UCEB2 string map child count");
+			else
+			{
+				for(u64 i = 0; error == "" && i < child_count; i++)
+				{
+					u64 key_len = 0, value_len = 0, value_children = 0;
+					if(!ucb_read_varint(encoded, offset, key_len) || key_len > encoded.size() - offset)
+					{
+						fail("invalid UCEB2 string map key");
+						break;
+					}
+					String key(encoded.data() + offset, (size_t)key_len);
+					offset += (size_t)key_len;
+					if(encoded.size() - offset < 2)
+					{
+						fail("unexpected end of UCEB2 string map value");
+						break;
+					}
+					u8 value_flags = (u8)encoded[offset++];
+					char value_type = encoded[offset++];
+					if(value_flags != 0 || value_type != 'S' || !ucb_read_varint(encoded, offset, value_len) || value_len > encoded.size() - offset)
+					{
+						fail("UCEB2 string map value must be a string scalar");
+						break;
+					}
+					String value(encoded.data() + offset, (size_t)value_len);
+					offset += (size_t)value_len;
+					if(!ucb_read_varint(encoded, offset, value_children) || value_children != 0)
+					{
+						fail("UCEB2 string map value cannot have children");
+						break;
+					}
+					decoded[std::move(key)] = std::move(value);
+				}
+				if(error == "" && offset != encoded.size())
+					fail("trailing bytes after UCEB2 string map");
+			}
+		}
+	}
+	if(error != "")
+	{
+		if(error_out)
+			*error_out = error;
+		return(false);
+	}
+	out = std::move(decoded);
+	if(error_out)
+		*error_out = "";
+	return(true);
+}
+#endif
+
 DValue ucb_decode(const String& encoded)
 {
 	DValue out;

src/wasm/backend.cpp

@@ -68,10 +68,10 @@ static String wasm_backend_ensure_started(Request* context)
 	}
 
 	g_wasm_worker = new WasmWorker(wc);
-	// Server configuration is finalized before render workers start. Retain one
+	// Server configuration is finalized before render workers start. Encode it
-	// native tree so per-request UCEB encoding can reference it without rebuilding
+	// once; each fresh guest decodes the cached flat map into its own Server.
-	// dozens of identical nodes; the guest still decodes it into fresh state.
 	g_wasm_worker->server_config_context = cfg;
+	g_wasm_worker->server_config_encoded = ucb_encode(g_wasm_worker->server_config_context);
 	g_wasm_init_error = g_wasm_worker->init();
 	if(g_wasm_init_error == "")
 		g_wasm_init_error = wasm_worker_prepare(*g_wasm_worker);
@@ -159,8 +159,6 @@ String wasm_backend_serve(Request& request, const String& entry_unit, const Stri
 		for(auto& entry : source)
 			ctx[key][entry.first] = entry.second;
 	};
-	if(request.server)
-		ctx["server_config"].set_reference(&g_wasm_worker->server_config_context);
 	copy_map(request.params, "params");
 	copy_map(request.get, "get");
 	copy_map(request.post, "post");
@@ -240,7 +238,21 @@ String wasm_backend_serve(Request& request, const String& entry_unit, const Stri
 	if(to_bool(request.server->config["WASM_BACKEND_VERBOSE"], false))
 	{
 		request.header["X-UCE-Backend"] = "wasm";
+		request.header["X-UCE-Wasm-Workspace-Setup-Us"] = std::to_string(response.workspace_setup_us);
 		request.header["X-UCE-Wasm-Workspace-Birth-Us"] = std::to_string(response.workspace_birth_us);
+		request.header["X-UCE-Wasm-Birth-Policy-Us"] = std::to_string(response.birth_policy_us);
+		request.header["X-UCE-Wasm-Birth-Import-Us"] = std::to_string(response.birth_import_us);
+		request.header["X-UCE-Wasm-Birth-Instantiate-Us"] = std::to_string(response.birth_instantiate_us);
+		request.header["X-UCE-Wasm-Birth-Exports-Us"] = std::to_string(response.birth_exports_us);
+		request.header["X-UCE-Wasm-Birth-Initialize-Us"] = std::to_string(response.birth_initialize_us);
+		request.header["X-UCE-Wasm-Context-Apply-Us"] = std::to_string(response.context_apply_us);
+		request.header["X-UCE-Wasm-Context-Bytes"] = std::to_string(response.context_bytes);
+		request.header["X-UCE-Wasm-Server-Config-Bytes"] = std::to_string(response.server_config_bytes);
+		request.header["X-UCE-Wasm-Context-Encode-Us"] = std::to_string(response.context_encode_us);
+		request.header["X-UCE-Wasm-Context-Allocate-Us"] = std::to_string(response.context_allocate_us);
+		request.header["X-UCE-Wasm-Context-Write-Us"] = std::to_string(response.context_write_us);
+		request.header["X-UCE-Wasm-Context-Guest-Apply-Us"] = std::to_string(response.context_guest_apply_us);
+		request.header["X-UCE-Wasm-Context-Free-Us"] = std::to_string(response.context_free_us);
 		request.header["X-UCE-Wasm-Workspace-Complete-Us"] = std::to_string(response.workspace_complete_us);
 		request.header["X-UCE-Wasm-Entry-Invoke-Us"] = std::to_string(response.entry_invoke_us);
 		request.header["X-UCE-Wasm-Entry-Load-Us"] = std::to_string(response.entry_load_us);

src/wasm/core.cpp

@@ -7,6 +7,7 @@
 
 #define __UCE_WASM_CORE__ 1
 #include "../lib/uce_lib.cpp"
+
 #include "../lib/mysql-connector.h"
 #include "../lib/sqlite-connector.h"
 
@@ -799,19 +800,26 @@ void uce_wasm_core_reset_request()
 	wasm_component_paths.clear();
 }
 
-// Host pushes the UCEB2-encoded request context into a guest buffer
+// Host pushes the worker-cached immutable configuration followed by the
-// (uce_alloc) and applies it here; mirrors the native param population.
+// dynamic UCEB2 request context into one guest buffer.
-int uce_wasm_apply_context(const char* buf, size_t len)
+int uce_wasm_apply_context(const char* config_buf, size_t config_len, const char* context_buf, size_t context_len)
 {
 	if(context == 0)
 		uce_wasm_core_init();
+	StringMap decoded_config;
 	DValue decoded;
 	String error;
-	if(!ucb_decode(String(buf, len), decoded, &error))
+	if(!ucb_decode_flat_string_map(String(config_buf, config_len), decoded_config, &error))
 	{
 		uce_host_log(3, error.data(), error.size());
 		return(1);
 	}
+	if(!ucb_decode(String(context_buf, context_len), decoded, &error))
+	{
+		uce_host_log(3, error.data(), error.size());
+		return(2);
+	}
+	wasm_server.config = std::move(decoded_config);
 	wasm_request.call = std::move(decoded);
 	DValue& applied = wasm_request.call;
 	auto apply_map = [](DValue* source, StringMap& dest) {
@@ -821,8 +829,6 @@ int uce_wasm_apply_context(const char* buf, size_t len)
 				dest[key] = item.to_string();
 			});
 	};
-	if(applied.key("server_config"))
-		apply_map(applied.key("server_config"), wasm_server.config);
 	apply_map(applied.key("params"), wasm_request.params);
 	wasm_request.response_code = wasm_request.params["GATEWAY_INTERFACE"] != "" ?
 		"Status: 200 OK" : "HTTP/1.1 200 OK";

src/wasm/worker.cpp

@@ -187,6 +187,7 @@ struct WasmRequestProfile
 	u64 context_apply_us = 0;
 	u64 context_apply_cpu_us = 0;
 	u64 context_bytes = 0;
+	u64 server_config_bytes = 0;
 	u64 context_encode_us = 0;
 	u64 context_allocate_us = 0;
 	u64 context_write_us = 0;
@@ -978,6 +979,7 @@ public:
 	std::optional<wasmtime::Linker> core_linker;
 	std::unique_ptr<wasmtime_instance_pre_t, WasmInstancePreDeleter> core_instance_pre;
 	DValue server_config_context;
+	String server_config_encoded;
 	struct CoreImport
 	{
 		String module;
@@ -1532,21 +1534,25 @@ public:
 			return(elapsed);
 		};
 		String encoded = ucb_encode(context_tree);
-		context_bytes = encoded.size();
+		server_config_bytes = worker.server_config_encoded.size();
+		context_bytes = server_config_bytes + encoded.size();
 		context_encode_us = phase_us();
 		int32_t guest_ptr = 0;
-		String error = call_core("uce_alloc", { (int32_t)encoded.size() }, &guest_ptr);
+		String error = call_core("uce_alloc", { (int32_t)context_bytes }, &guest_ptr);
 		context_allocate_us = phase_us();
 		if(error != "")
 			return(error);
 		if(guest_ptr == 0)
 			return("guest uce_alloc failed for context buffer");
-		error = guest_write((u32)guest_ptr, encoded);
+		error = guest_write((u32)guest_ptr, worker.server_config_encoded);
+		if(error == "")
+			error = guest_write((u32)guest_ptr + (u32)server_config_bytes, encoded);
 		context_write_us = phase_us();
 		if(error != "")
 			return(error);
 		int32_t rc = 0;
-		error = call_core("uce_wasm_apply_context", { guest_ptr, (int32_t)encoded.size() }, &rc);
+		error = call_core("uce_wasm_apply_context", { guest_ptr, (int32_t)server_config_bytes,
+			guest_ptr + (int32_t)server_config_bytes, (int32_t)encoded.size() }, &rc);
 		context_guest_apply_us = phase_us();
 		if(error != "")
 			return(error);
@@ -2592,6 +2598,7 @@ private:
 						response["context_apply_us"] = (f64)self->context_apply_us;
 						response["context_apply_cpu_us"] = (f64)self->context_apply_cpu_us;
 						response["context_bytes"] = (f64)self->context_bytes;
+						response["server_config_bytes"] = (f64)self->server_config_bytes;
 						response["context_encode_us"] = (f64)self->context_encode_us;
 						response["context_allocate_us"] = (f64)self->context_allocate_us;
 						response["context_write_us"] = (f64)self->context_write_us;