AWARE [SYSTEMS] Imaging expertise for the Delphi developer
AWare Systems, Imaging expertise for the Delphi developer, Home TIFF and LibTiff Mailing List Archive

LibTiff Mailing List

TIFF and LibTiff Mailing List Archive
May 2010

Previous Thread
Next Thread

Previous by Thread
Next by Thread

Previous by Date
Next by Date

Contact

The TIFF Mailing List Homepage
This list is run by Frank Warmerdam
Archive maintained by AWare Systems



Valid HTML 4.01!



Thread

2010.05.10 09:35 "Increasing the number of files loadable through libtiff", by Simon R Proud
2010.05.10 13:27 "Re: Increasing the number of files loadable through libtiff", by Edward Lam
2010.05.10 15:30 "Re: Increasing the number of files loadable through libtiff", by Simon R Proud
2010.05.10 15:51 "Re: Increasing the number of files loadable through libtiff", by Bob Friesenhahn
2010.05.10 16:17 "Re: Increasing the number of files loadable through libtiff", by Olivier Paquet
2010.05.10 19:10 "Re: Increasing the number of files loadable through libtiff", by Bob Friesenhahn
2010.05.10 20:07 "Re: Increasing the number of files loadable through libtiff", by Olivier Paquet
2010.05.10 14:01 "Re: Increasing the number of files loadable through libtiff", by Olivier Paquet

2010.05.10 15:51 "Re: Increasing the number of files loadable through libtiff", by Bob Friesenhahn

On Mon, 10 May 2010, Simon R. Proud wrote:
>
> Out of interest: Is there any reason why memory mapping is enabled 
> by default? Enabling it causes problems like the ones I have been 
> having and, at least in my case, offers no speed advantage.

Libtiff seems to do a lot of file seeking and small reads because of 
the TIFF directory structures and organization.  The memory mapping 
tends to help hide this because it provides a caching effect.  It also 
helps quite a lot if the input file is opened and read several times 
without any other intermediate memory-hogging process which might lose 
the already cached data.

Regardless, my own application defaults to not using memory mapping 
for input files.

Bob
-- 
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/