bug#5833: 23.1.94; Opening files on network shares on w32 is slow

[Mathias Dahl]

Hi, Eli, thanks for looking into this!

> Does it help to set w32-get-true-file-attributes to a nil value?

No.

> Also, is this a regression in the last pretest?  IOW, when was the
> last time you tried visiting files on that remote file system and it
> was much faster than what you see now with 23.1.94?

As far as I can see this has been slow for quite a while. I have
recently reinstalled my PC so I don't have the old versions with me. I
downloaded 22.3 and it was even slower.

Last year (I think it was) I reported a similar issue, which was
fixed. That performance issue could be worked around by setting the
variable above. That problem was even worse though.

The reason I have noticed this at all is that one of our servers has
moved to another office lately, so the network of course plays a role
in this. However, there is still the question what Emacs does that
Notepad don't (well, I know, a lot, but computers are fast nowadays)
that makes for the difference in opening files on shares (it could be
a problem locally as well but maybe it is so fast that I don't
notice).

Just now I tested this scenario in the latest pretest: I opened (from
Dired) a file only 800 bytes in size. It took 7 seconds. I then opened
another file, over 100 000 bytes and that also took 7 seconds. Opening
the larger of the files in Notepad takes just above a second.

If there are any other tests I can do, please let me know. I currently
don't have a way to compile the source myself on w32, just so that you
know.

Thanks!

/Mathias