While setting up my prompt with fish_async_prompt I noticed that after adding multiple async functions it started getting noticable slow. After a bit of digging around I found that adding an additional async function adds around 80ms of execution time to fish_prompt:
# 1 async function configured in async_prompt_functions
$ time fish_prompt
________________________________________________________
Executed in 87.69 millis fish external
usr time 62.95 millis 243.00 micros 62.71 millis
sys time 21.77 millis 885.00 micros 20.89 millis
# 2 async functions configured in async_prompt_functions
$ time fish_prompt
________________________________________________________
Executed in 166.54 millis fish external
usr time 123.61 millis 1.29 millis 122.32 millis
sys time 41.11 millis 3.16 millis 37.94 millis
# 3 async functions configured in async_prompt_functions
$ time fish_prompt
________________________________________________________
Executed in 256.66 millis fish external
usr time 186.53 millis 1.44 millis 185.08 millis
sys time 64.06 millis 3.92 millis 60.14 millis
While having 1 function like this isn't really noticable as it is below 100ms, this starts adding up quickly and becomes really noticable, especially when the whole goal is to make the prompt faster with making it async.
I didn't dig deep enough to investigate why reading from temporary files make this process this slow, but quickly doing a proof of concept using universal variables instead showed a huge performance increase:
# 5 async functions configured in async_prompt_functions
$ time fish_prompt
________________________________________________________
Executed in 292.00 micros fish external
usr time 265.00 micros 265.00 micros 0.00 micros
sys time 28.00 micros 28.00 micros 0.00 micros
I've only tested it on my local setup (MacOS 13.2.1, fish 3.7.1), so I can't comment if this has unintended side effects on other systems, but since this variable handling is part of the shell itself I would presume no.
While setting up my prompt with fish_async_prompt I noticed that after adding multiple async functions it started getting noticable slow. After a bit of digging around I found that adding an additional async function adds around 80ms of execution time to
fish_prompt:While having 1 function like this isn't really noticable as it is below 100ms, this starts adding up quickly and becomes really noticable, especially when the whole goal is to make the prompt faster with making it async.
I didn't dig deep enough to investigate why reading from temporary files make this process this slow, but quickly doing a proof of concept using universal variables instead showed a huge performance increase:
I've only tested it on my local setup (MacOS 13.2.1, fish 3.7.1), so I can't comment if this has unintended side effects on other systems, but since this variable handling is part of the shell itself I would presume no.