Re: 22.1.50; insert-file-contents is slow under tramp

[David Kastrup <dak@gnu.org>]

Richard Stallman <rms@gnu.org> writes:

>     > The major bottleneck is `accept-process-output', which returns only
>     > small chunks when called again and again. With a `sleep-for' between
>     > two calls, I have improved the performance (but not dramatically).
>
>     Same old scheduler problem that prompted both of
>
>     w32-pipe-read-delay
>     process-adaptive-read-buffering
>
>     Maybe you should try setting process-adaptive-read-buffering to a
>     non-nil non-t value?
>
> Should the defaults for any of these be changed?

It is hard to say: basically, they work around deficiencies in the CPU
schedulers of the respective operating systems.

Linux is supposed to get CFS, "completely fair scheduling" in its next
released version, something like 2.6.23.  This should quite help with
the original problem.  Not because of fairness, but because of being
different: pretty much _any_ scheduler should behave better here than
the previous "context switch whenever possible" scheduling strategy.

I was actually surprised to see w32-pipe-read-delay crop up in my
apropos-documentation search.  From the description, it sounds like it
addresses a similar problem, so perhaps it might have been made
redundant by process-adaptive-read-buffering _if_ the latter does its
job reasonably well under Windows.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum