Gentoo Archives: gentoo-performance

From: "Douglas Breault Jr." <GenKreton@×××××××.net>
To: gentoo-performance@l.g.o
Subject: Re: [gentoo-performance] swap?
Date: Sun, 01 Aug 2004 04:33:51
Message-Id: 20040801003315.73893746.GenKreton@comcast.net
In Reply to: Re: [gentoo-performance] swap? by Colin Kingsley
Even on laptops swap has a purpose and should be used to increase space but there is a definite lack of control over it beyond the very obscure swapiness variable. It's not horribly bad right now but it seems too many people want to make this worse. The laptop sysctl variable is the closest thing we have unfortunately.

There needs to be a balance between power and performance when necessary. Swap is good stuff sometimes.

On Sun, 1 Aug 2004 00:17:47 -0400
Colin Kingsley <ckingsley@×××××.com> wrote:

> how is that "disturbing"? you _can_ > turn off swap for power reasons if you want too. > > it was a discussion about swap, what were you expecting? > by the way, I happen to be on a laptop myself. > > > On Sun, 1 Aug 2004 00:06:12 -0400, Douglas Breault Jr. > <genkreton@×××××××.net> wrote: > > The dsturbing thing about those threads you posted up is that they completely ignore those people running laptops who may also want to not swap often because it spins up the harddrive and causes a spike in power consumption everytime this happens. > > This is a problem I've experience with the CK patch set. > > > > On Fri, 30 Jul 2004 21:22:17 +0200 > > > > > > "Florian Koenig" <k0255220@××××××××××××××××××××.at> wrote: > > > > > > > Also, when I do > > > > > > > > > > free > > > > > > > > > > it shows no swap is used even though physical memory level is 98%. > > > > > > > > free shows no swap used on my system either. and 90% or more physical > > > > memory use is standard for the linux kernel. > > > > > > Exactly. In contrast to Windows NT/2000/XP, which tries to swap out as much pages as possible, Linux tries to keep the memory mostly filled. Lots of the memory gets used as cache and buffer so you might actually gain some performance. > > > > > > The difference between Windows and Linux stems from their different origins. Linux/Unix was always meant to be a server system where the set of running processes doesn't change that often. Therefore it tries to keep pages in memory for as long as possible. > > > > > > Windows' approach to the problem is geared to desktop performance and so it swaps out 'unused' pages as soon as possible to free memory and keep startup time short for programs being loaded. > > > > > > The behaviour of Linux is actually hotly debated by the developers as you can see on these two pages, which btw also include some hints on how to tune swapping: > > > > > > http://kerneltrap.org/node/view/3000 > > > http://kerneltrap.org/node/view/3202 > > > > > > Have a nice weekend and kind regards > > > floki > > > > > > > > > -- > > > gentoo-performance@g.o mailing list > > > > > > > > > > > -- > gentoo-performance@g.o mailing list >

Replies

Subject Author
Re: [gentoo-performance] swap? Colin Kingsley <ckingsley@×××××.com>