Re: Making Cygwin More Tolerant of Orphaned SIDs?

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Apr 14 07:24, Bryan Berns wrote:
> On Tue, Apr 14, 2015 at 4:00 AM, Corinna Vinschen
> >
> > The problem is that Cygwin, or any other tool trying to resolve SIDs
> > doesn't know a SID won't resolve before it tried.  And then it's an
> > OS function which takes its time.  It's like checking for network
> > machines providing shares.  Sometimes this test takes ages, but in
> > this case, fortunately, you see that it takes ages in Explorer as
> > well.
> >
> > As for ACLs, you can alleviate the problem somewhat by running cygserver
> > on the machine, which allows to cache SIDs for all processes.  So only
> > the first process trying the SID will take time, followup processes will
> > get the cached results from cygserver.
> >
> > Other than that, except for ignoring ACLs entirely (noacl) I have
> > no idea how to solve this problem differently.
> 
> Yes, I understand there's nothing Cygwin can do beforehand -- that
> means sense.  I guess what I'm saying is that Cygwin doesn't appear to
> be caching SIDs in certain scenarios.
> 
> For example, I create a whole bunch of files (like 5000),  I use
> icacls to append a new ACE.  Then I do a 'time ls -l
> /cygdrive/c/somedir/*'.  Takes four seconds.  In the same Cygwin
> session, I remove the local group (net localgroup testgroup /delete).
>  I do the same 'time ls -l /cygdrive/c/somedir/*'.  Takes 20 seconds.
> Subsequent runs in the also take 20 seconds.  Since I'm able to
> continue to see the slowdown in the same session, cygserver wouldn't
> help right?
> 
> Is the above expected?

Yes.  Without cygserver, caching only works from parent to child process.
One run of ls can't cache data for a parallel run of ls in trhe same
session.  As, btw., explained in the documentation:

  https://cygwin.com/cygwin-ug-net/ntsec.html


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

Attachment: pgp66H2lUmPUU.pgp
Description: PGP signature