Improving OOTB performance

Len Ovens len at
Mon May 14 03:41:37 UTC 2012

On Sun, May 13, 2012 10:36 am, Sergey \"Shnatsel\" Davidoff wrote:

> Another useful thing would be avoiding swapping for as long as possible.
> In
> Linux there are several facilities competing for RAM - in Ubuntu's stock
> configuration executable code often gets swapped to disk to make way for
> various caches. Here's the best article I've found about it so far:
> there's something better in kernel documentation, but I'm not aware
> of that.

I am not sure where to stand on this. Back in the days of 4Meg (not Gig)
being a normal size. Swap space was mandatory. X needed 8Meg and kernel
building needed 16M (and everyone built there own kernel because modules
had yet to be introduced and 16M of ram cost more than the rest of the
computer) Swap size was determined by what needed to be done. Now, we have
big memory, swap size is suggested at 100% ram size. So I have 1G of ram,
ubuntu install sets swap at 1G.... maybe it is time to start running with
no swap. If I go and buy 2G of ram and have no swap... I have the same
visible ram (more because the ram used to deal with swapping is free) but
no swapping to worry about. If I use something that takes more than those
2G of ram the kernel kills it, but so what? It would have done that anyway
with 1G ram and 1G swap... but everything up to that it fast. Hey we are
playing with audio, we have to stay within the physical ram anyway....
lets kill swap.

Thats the audio argument. However, someone who is dealing with a large
highrez graphic might feel differently. They may have only 20% of the
picture even on the screen and work on the portion for several minutes
before moving the window over and doing something else. They may need swap
just to do their work... I'm thinking cinipaint where a picture(or frame)
of the same rez as gimp can still use 4 times the memory just for colour
depth and may have much more rez as well. There may be several of these
images in memory at once too. Swap might be needed just to do the job.

Ok, one more thing about audio. Good audio tools lock the ram they need to
operate from being swapped anyway. This is why we set memlock so high.

This is one of those areas where each user needs to be able to find out
what the options are and set their machine up to meet their requirements.
US could help by having a great setup tool that makes this easy (easier).


Len Ovens

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