On Fri, Nov 12, 2004 at 02:13:46AM +0200, Steve Stavropoulos wrote:
> > The most important thing to do is balance your tile cache setting, as
> > you've already found. You want it large enough that GIMP doesn't have
> > to use its own virtual memory, but not so large that the OS has to use
> > virtual memory to accommodate it. On a 2GB machine, I'd set to about
> > 1.5GB, assuming GIMP has pretty much free reign over the machine.
> If the OS has better virtual memory than what available to gimp, then
> you would want to use that one. In Linux, I think in most cases, you
> would want to use the (often in multiple disks) swap partitions/files
> available to the OS.
You don't want to use virtual memory if you don't have to. So give as
much memory to GIMP as possible without making the OS swap.
> If you want to keep the system friendly to other apps as well, you
> might consider a smaller than the available memory tile cache
> PS. SOT: many people have more than one disk on their system. In that
> case they should consider these example fstab entries:
> /dev/hdf1 swap swap defaults,pri=0 0 0
> /dev/hdg5 swap swap defaults,pri=0 0 0
> /stuff/swap swap swap defaults,loop,pri=0 0 > 0
> (you might spell it as: "raid0 swap with three disks")
It has always been pointed out that the access patterns of GIMP are very
specific to image operations - the tile cache is there because it gives
a significant advantage compared to the OS's virtual memory. Besides,
you get the advantage that the tile cache can be a lot larger than
usable physical memory.
BTW: You can easily try OS-only virtual memory by setting the tile cache
very large (like all of your swap), then compare whether it performs
better than limiting the tile cache to physical memory (minus some
amount for OS, Window environment and GIMP itself).
 Working ain't gonna be fun - I once had an A1 poster at 300 dpi on
an 6 GB machine and GIMP's swap grow as large as another 6 GB since GIMP
didn't seem to be able to use more than 2 or 3 GB of memory altogether.
(Is there a known limitation regarding maximum usable memory?)
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