Gimp - 2.4 Guía Del Usuario
GNU Image Manipulation Program
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the work on the pictures fast and comfortable for the user. That Data memory, during the treatment, is organized in buffered
blocks of graphic data, wich could exists in two different form of data memory: in the slow not removable disk or in the fast
main RAM memory. GIMP uses preferibly the last one but, when it is scarse, the first is accessed for the remaining data. These
chunks of graphic data are commonly referred as "tiles" and the entire system si called "tile cache".
blocks of graphic data, wich could exists in two different form of data memory: in the slow not removable disk or in the fast
main RAM memory. GIMP uses preferibly the last one but, when it is scarse, the first is accessed for the remaining data. These
chunks of graphic data are commonly referred as "tiles" and the entire system si called "tile cache".
A low value for tile cache means that GIMP sends data to the disk very quickly, not making real use of the available RAM,
and making the disks work for no real reason. Too high a value for tile cache, and other applications start to have less system
resources, forcing them to use swap space, which also makes the disks work too hard; some of them may even terminate or start
to malfunction due lack of RAM.
and making the disks work for no real reason. Too high a value for tile cache, and other applications start to have less system
resources, forcing them to use swap space, which also makes the disks work too hard; some of them may even terminate or start
to malfunction due lack of RAM.
How do you choose a number for the Tile Cache size? Here are some tips to help you decide what value to use, as well as a few
tricks:
tricks:
• The easiest method is to just forget about this and hope the default works. This was a usable method when computers had little
RAM, and most people just tried to make small images with GIMP while running one or two other applications at the same
time. If you want something easy and only use GIMP to make screenshots and logos, this is probably the best solution.
time. If you want something easy and only use GIMP to make screenshots and logos, this is probably the best solution.
• If you have a modern computer with plenty of memory–say, 512 MB or more–setting the Tile Cache to half of your RAM will
probably give good performance for GIMP in most situations without depriving other applications. Probably even 3/4 of your
RAM would be fine.
RAM would be fine.
• Ask someone to do it for you, which in the case of a computer serving multiple users at the same time can be a good idea: that
way the administrator and other users do not get mad at you for abusing the machine, nor do you get a badly underperfoming
GIMP. If it is your machine and only serves a single user at a given time, this could mean money, or drinks, as price for the
service.
GIMP. If it is your machine and only serves a single user at a given time, this could mean money, or drinks, as price for the
service.
• Start changing the value a bit each time and check that it goes faster and faster with each increase, but the system does not
complain about lack of memory. Be forewarned that sometimes lack of memory shows up suddenly with some applications
being killed to make space for the others.
being killed to make space for the others.
• Do some simple math and calculate a viable value. Maybe you will have to tune it later, but maybe you have to tune it anyway
with the other previous methods. At least you know what is happening and can get the best from your computer.
Let’s suppose you prefer the last option, and want to get a good value to start with. First, you need to get some data about your
computer. This data is the amount of RAM installed in your system, the operating system’s swap space available, and a general
idea about the speed of the disks that store the operating system’s swap and the directory used for GIMP’s swap. You do not need
to do disk tests, nor check the RPM of the disks, the thing is to see which one seems clearly faster or slower, or whether all are
similar. You can change GIMP’s swap directory in the Folders page of the Preferences dialog.
computer. This data is the amount of RAM installed in your system, the operating system’s swap space available, and a general
idea about the speed of the disks that store the operating system’s swap and the directory used for GIMP’s swap. You do not need
to do disk tests, nor check the RPM of the disks, the thing is to see which one seems clearly faster or slower, or whether all are
similar. You can change GIMP’s swap directory in the Folders page of the Preferences dialog.
The next thing to do is to see how much resources you require for other apps you want to run at the same time than GIMP. So
start all your tools and do some work with them, except GIMP of course, and check the usage. You can use applications like free
or top, depending in what OS and what environment you use. The numbers you want is the memory left, including file cache.
Modern Unix keeps a very small area free, in order to be able to keep large file and buffer caches. Linux’s free command does
the maths for you: check the column that says ‘free’, and the line ‘-/+ buffers/cache’. Note down also the free swap.
start all your tools and do some work with them, except GIMP of course, and check the usage. You can use applications like free
or top, depending in what OS and what environment you use. The numbers you want is the memory left, including file cache.
Modern Unix keeps a very small area free, in order to be able to keep large file and buffer caches. Linux’s free command does
the maths for you: check the column that says ‘free’, and the line ‘-/+ buffers/cache’. Note down also the free swap.
Now time for decisions and a bit of simple math. Basically the concept is to decide if you want to base all Tile Cache in RAM,
or RAM plus operating system swap:
or RAM plus operating system swap:
1. Do you change applications a lot? Or keep working in GIMP for a long time? If you spend a lot of time in GIMP, you
can consider free RAM plus free swap as available; if not, you need to go to the following steps. (If you’re feeling unsure
about it, check the following steps.) If you are sure you switch apps every few minutes, only count the free RAM and just
go to the final decision; no more things to check.
about it, check the following steps.) If you are sure you switch apps every few minutes, only count the free RAM and just
go to the final decision; no more things to check.
2. Does the operating system swap live in the same physical disk as GIMP swap? If so, add RAM and swap. Otherwise go to
the next step.
3. Is the disk that holds the OS swap faster or the same speed as the disk that holds the GIMP swap? If slower, take only the
free RAM; if faster or similar, add free RAM and swap.
4. You now have a number, be it just the free RAM or the free RAM plus the free OS swap. Reduce it a bit, to be on the safe
side, and that is the Tile Cache you could use as a good start.