bug#49714: 28.0.50; TRAMP burns CPU and has insufficient user reporting when using xxxx-sk SSH keys

[Michael Albinus]

Dima Kogan <dima@secretsauce.net> writes:

>>> There should be a loop, but emacs shouldn't be using all my CPU cycles
>>> while waiting for user interaction. Emacs can select() on the ssh
>>> process file descriptor, and sleep until the ssh process has stuff to
>>> say.
>>
>> Well, I'm on Lisp level. I just have accept-process-output, and in my
>> loop I check whether there is new output. There's no low level API to
>> let Emacs sleep for the ssh process file descriptor.
>
> It just sounds unbelievable that emacs can't do blocking reads from the
> lisp level. Let me look at (accept-process-output)

accept-process-output could block. But it blocks the whole Emacs then,
which isn't what we want.