Exported async functions have been changed in November to receive their arguments on the value stack, so these function calls now impose less overhead.
Imported async functions on the other hand still use a heap allocated list to pass arguments. While this is motivated by minimal overhead for back-pressure it penalizes the common case of async function calls with few parameters, e.g. a string or list. The overhead to store the arguments on the host in the (less likely?) back-pressure case could be acceptable in comparison to this unconditional heap allocation on the client side.
When I brought this up in bytecodealliance/wit-bindgen#1082 (comment) Joel proposed to open discussion here.
Exported async functions have been changed in November to receive their arguments on the value stack, so these function calls now impose less overhead.
Imported async functions on the other hand still use a heap allocated list to pass arguments. While this is motivated by minimal overhead for back-pressure it penalizes the common case of async function calls with few parameters, e.g. a string or list. The overhead to store the arguments on the host in the (less likely?) back-pressure case could be acceptable in comparison to this unconditional heap allocation on the client side.
When I brought this up in bytecodealliance/wit-bindgen#1082 (comment) Joel proposed to open discussion here.