bug#74855: 30.0.92; dired - slow copy across (wireless) LAN

[Michael Albinus via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Stefan Kangas <stefankangas@gmail.com> writes:

Hi Stefan,

>> Tramp's "ssh" method is not suited for this use case. It encodes the
>> local file with base64, and decodes it when it has been arrived on the
>> remote side.
>>
>> For this given use case, Tramp's "scp" method is better suited. See the
>> discussion in the manual, (info "(tramp) Connection types") and (info
>> "(tramp) Frequently Asked Questions") , the entry "How to speed up TRAMP".
>
> Thanks.  Would it be possible to detect this situation and either warn
> the user about it, or even automatically switch over to scp?

What would be the check? "A user wants to copy 600 files, with about 2GB
data total, via ssh"? Tramp doesn't know this, it works file-wise. Such a
check must reside in dired, but I still doubt we'll find a good rule.

And, btw, a file with a size less that tramp-copy-size-limit (10240 bytes)
would still be copied via ssh, and not via scp. This check must also be
part of the rule.

Best regards, Michael.