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

Corinna Vinschen corinna-cygwin@cygwin.com
Thu Oct 7 14:26:00 GMT 2010


On Oct  7 15:45, Corinna Vinschen wrote:
> Ok, here's one for the records.
> 
> In your original patch on the cygwin-patches ML you implemented the
> fs_info caching using the pathname.  I still don't think this is correct
> for the reasons given in another mail.  However, maybe we can use it
> nevertheless like this:
> 
> - If we don't find a path prefix matching the incoming path, call
>   symlink_info::check.
> 
> - Otherwise we have a cached fs_info for the path prefix:
> 
>   - If the path is NFS, call check.
>   - Otherwise, if the calling function doesn't need st_nlink or st_mode,
>     call xcheck.
>   - Otherwise, call check.

      - In check, test for samba and use GENERIC_WRITE
      - otherwise use FILE_READ_ATTRIBUTES etc.

> - In check and xcheck, always fetch fs_info using the current method.
>   Write back to path-based cache so we use the info the next time
>   around.

Corinna

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



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