In regard to: Re: Re: Tile Cache Size, Marc Lehmann said (at 10:35pm on Nov...: >On Mon, Nov 01, 1999 at 10:22:08PM +0100, "Guillermo S. Romero / Familia Romero" <famrom@xxxxxxxxxxx> wrote: >> Yes, but Gimp swaps to files, while system normally swaps to partition, and >> if the admin is smart, to a fast disk which main (unique?) task is swapping, >> maybe even sharing swap among a group of disks. Kernels swap is optimized (I >> hope it is, otherwise... argh!), we dunno about Gimp. > >The point is that the kernel keyes the swap by memory address (physical or >virtual does not matter). Which means the keys are basically random. > >Gimp can use optimized ordering (e.g. group tiles that are near eahc other >near on the medium) that no kernel can use. > >Once you start to seek your performance is gone, _no matter_ how fast your >physical swap may be (for linear r/w). Wouldn't the situation be even worse, then, if we're going through the filesystem and there's "average" fragmentation? You seem to be assuming that the filesystem allocation will be contiguous (or at least close) on disk, but can you really make that assumption? Tim -- Tim Mooney mooney@xxxxxxxxxxxxxxxxxxxxxxxxx Information Technology Services (701) 231-1076 (Voice) Room 242-J1, IACC Building (701) 231-8541 (Fax) North Dakota State University, Fargo, ND 58105-5164
