Re: swap prefetching merge plans

From: Helge Hafting
Date: Fri Mar 24 2006 - 03:13:35 EST


Hemmann, Volker Armin wrote:

On Thursday 23 March 2006 12:47, you wrote:


On Thursday 23 March 2006 10:26, Nick Piggin wrote:


Hemmann, Volker Armin wrote:


Hi,

I am just a user, but I would love to see this feature.

After compiling stuff, I have usually some kb in swap (300kb, 360 kb),
and lots of free ram. But even this few kb make my KDE desktop extremly
sluggish. It feels, like every byte is fetched individually and always
the wrong stuff ends in swap.


I'm almost positive this wouldn't be the cause of your problems (even a
slow disk could read all these blocks in, randomly, in under 2 seconds,
assuming they're spread from one end of the platters to the other).


Maybe he meant 300 megabytes.



no, I meant kilobytes.

And swapoff really helps.

Some moments of disk activity, and bang, computer is as fast as always again.

But having stuff in swap? konqueror is slow, kmail is slow, opening a konsole session, slow. Everything crawls with lots of disk access.

next time the computer is slow, I could gather some data - if you tell me, what is interessting for you, I'll save it.


Strange indeed. 300k in swap is nothing - I often enough
have 50M in swap without a slowdown - but then, I don't
run kde.

Be aware that the 300k in swap doesn't account for all that
is removed from memory. Linux don't put executable code
in swap - such stuff is simply dropped because it can
be reloaded from the executable files anytime.
I don't think swapoff+swapon helps with that though.

Helge Hafting

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