Re: Willing to debug bug #3542 (23.0.94; File access via UNC path slow again under Windows)

[Mathias Dahl]

> First, I don't see a ~100-fold slowdown, I see only a 10-fold slowdown
> (vs Emacs 22.3).  This is with a directory that has ~130
> subdirectories.

The more files there are, the bigger the slowdown seems to be, in my tests.

>  . Do you see significant difference in speed with cold and hot cache?
>   That is, if you run Dired on the above directory, then kill the
>   Dired buffer and immediately run Dired again on the same directory,
>   what times do you see then in Emacs 23?

Hehe, it got even worse the second time :)

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

Woooo! Um, yes... It helped all right. From 85 (first try) and 115
(second try as per reuest above), down to 1,4 s. Shall we call that as
success? :)

>   previous test shows a significant speedup with hot cache, please
>   try this with a cold cache, which may mean rebooting the machine
>   where you are trying this, or maybe waiting long enough for the
>   cache to "cool down" and in addition restarting Emacs (to get rid
>   of Emacs's internal caching).

I assume I don't need to test this now. If I do, ask me again.

>  . If w32-get-true-file-attributes does have a significant effect,
>   please tell how many different user names and group names you see
>   in the listing presented by "C-x d".

It looks like this:

  //gbgfs1/archive75:

  total used in directory 8728 available 8198544

  drwxrwxrwx  1 Administrators Domain Users       0 1970-01-01  .

  dr-xr-xr-x  1 mdahse         Domain Users       0 1970-01-01  ..

  drwxrwxrwx  1 demoruntime    Domain Users       0 2008-12-05  _ConfigBuild

  drwxrwxrwx  1 demoruntime    Domain Users       0 2008-06-09  acadc

...

and then all other lines after that has the same user and group names.
The one that differs above (mdahse) is my own username.

>> Not yet.  But perhaps install StraceNT
>> (http://stracent.en.softonic.com/) and see what are the differences
>> between Emacs 22 and Emacs 23.  Maybe you will even be able to see the
>> system call(s) that take most of this extra time.
>
> Did you have a chance to do this?  If so, can you post the results?

Not yet, no. Is it still interesting?

/Mathias