flush LuaJIT compiled code cache before executing commands

2 files changed, 19 insertions, 0 deletions

diff --git a/applause.c b/applause.c
index 4a5f453..6c3a2a3 100644
--- a/applause.c
+++ b/applause.c
@@ -638,6 +638,20 @@ do_command(lua_State *L, const char *command)
 	int stack_top;
 	char *buffer;
 
+	/*
+	 * EXPERIMENTAL: I found that performance decreases
+	 * progressively when running one and the same command.
+	 * This is probably because the limited space for the
+	 * compiled code gets filled up rapidly and LuaJIT
+	 * resorts to using the interpreter.
+	 * This flashes the entire code cache for every
+	 * new command and improves matters.
+	 * TODO: It would probably be a good idea to increase the
+	 * total size of the code cache and give some indication
+	 * of its usage (e.g. in the prompt).
+	 */
+	luaJIT_setmode(L, 0, LUAJIT_MODE_ENGINE | LUAJIT_MODE_FLUSH);
+
 	/* the error hanlder function for lua_pcall() */
 	lua_pushcfunction(L, traceback);
 
diff --git a/applause.lua b/applause.lua
index 5fe77e4..dd1d78f 100644
--- a/applause.lua
+++ b/applause.lua
@@ -400,6 +400,11 @@ function Stream:play()
 	-- Perform garbage collection cycle and turn it off
 	-- temporarily. This improves the realtime properties
 	-- of the sample generation loop below.
+	-- FIXME: Since stopping the garbage collector here
+	-- (in the Lua/C code this did not happen!?), memory
+	-- consumption increases constantly. Perhaps it is a
+	-- good idea to tweak garbage collection during the
+	-- generator loop.
 	collectgarbage("collect")
 	collectgarbage("stop")