[KimDaBa] Multithreaded image loader?

Robert L Krawitz rlk at alum.mit.edu
Mon Jan 10 08:39:24 CET 2005


   From: "Jesper K. Pedersen" <blackie at blackie.dk>
   Date: Mon, 10 Jan 2005 14:30:05 +0100
   Cc: Robert L Krawitz <rlk at alum.mit.edu>

   On Monday 10 January 2005 14:24, Robert L Krawitz wrote:
   | I notice a comment in the image manager that the image loader can't be
   | made multithreaded because the JPEG loader isn't MT-safe.  Is this an
   | issue in the JPEG library or somewhere else?  Particularly (but not
   | exclusively) on an SMP/CMP or HT system, multithreading the loader
   | might offer a significant performance improvement.

   Well. only if you have more than one cpu in your system, or?

Not necessarily.  While that's becoming increasingly common
(particularly in form of hyperthreading), the ability to overlap I/O
with computation may offer benefits even on single CPU systems.  If
the I/O system can reorder requests to improve latency (which is
normally the issue when loading thumbnails), there may be considerable
benefit, particularly on a fast CPU.

This is the kind of thing where it's often hard to predict what's
going to happen, and experimentation yields benefits.

-- 
Robert Krawitz                                     <rlk at alum.mit.edu>

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lpf at uunet.uu.net
Project lead for Gimp Print   --    http://gimp-print.sourceforge.net

"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton



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