Re: Cygwin Filesystem Performance degradation 1.7.5 vs 1.7.7, and methods for improving performance

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

On Oct  7 16:54, Derry Shribman wrote:
> Yet another possible improvement on this line that could be
> implemented in the future after the fs_info caching is added:
> 
> We see that reading actual DATA from a file REALLY slow: on Windows
> with AV its slow due to the AV scanning the file, and on Network
> Shares (Samba/NFS) - it means create-read-close (3 round-trips) - as
> opposed to network-open-info (1 round-trip).
> 
> Cygwin reads file content for symlinks (!<symlink>) and files that
> may be executable (#!/bin/xxx magic).
> 
> A cache could be added for this using the same cache mechanism. The
> cache-validation can be done with the quick QAF() (or QIF/QDF), and
> then the read the potential symlink/executable file's header only if
> needed.

I'm wondering if that really is such a big problem.  It depends how
often a symlink is accessed.  This might be worth to consider for
symlinks to directories, but it's probably not noticable for symlinks to
files.  Anyway, yes, we can try that at one point.


Corinna

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