Messages in this thread | | | Subject | Re: why swap at all? | From | FabF <> | Date | Wed, 02 Jun 2004 19:06:44 +0200 |
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On Wed, 2004-06-02 at 13:42, Con Kolivas wrote: > On Wed, 2 Jun 2004 15:38, FabF wrote: > > On Wed, 2004-06-02 at 01:17, Bernd Eckenfels wrote: > > > In article <200406012000.i51K0vor019011@turing-police.cc.vt.edu> you > wrote: > > > > out (unlike some, I don't mind if Mozilla or OpenOffice end up out on > > > > disk after extended inactivity - but if my window manager gets swapped > > > > out, I get peeved when focus-follows-mouse doesn't and my typing goes > > > > into the wrong window or some such... ;) > > > > > > Yes but: your wm is so often used/activated it will not get swaped out. > > > But if your mouse passes over mozilla and tries to focus it, then you > > > will feel the pain of a swapped-out x program. > > > > Exactly ! > > Does autoregulated VM swap. patch could help here ? > > Unless you are pushing the limits of your available ram by your usage pattern > then yes the autoregulated swappiness patch should help. > > available here: > http://ck.kolivas.org/patches/2.6/2.6.7-rc2/patch-2.6.7-rc2-am11 > > Just a brief word that might clarify things for people. It seems this huge > swap discussion centres around 2 different arguments. Akpm has said that the > correct way for the vm to behave is that of swappiness=100. Desktop users > note they have less swap out of the programs they use with swappiness 0 or > their swap turned off. When your swappiness is set high, the current vm > decisions are the fastest they can be, but when you go back to your > applications they will take longer to restart. When your swappiness is set > low your applications will restart rapidly, but the current vm will be doing > more work and be slower. Most benchmarks will show the latter, but most > desktop users will feel the former and not really notice the latter. > > Try the little experiment to see: Boot with mem=128M and try to compile a 2.6 > kernel with all the debugging symbols option enabled - do this with > swappiness set to 0 and then at 100. You'll see it compile much faster at > 100. Yet you know that if you set your swappiness to 0 mozilla will load > faster next time you use it on your desktop during your normal usage pattern > (of course you'd probably be using mozilla on a system with a bit more than > 128M ram but this helps demonstrate the point). > > Does this explain in coarse examples to the desktop users why ideal systems > shouldn't be swap disabled or swappiness=0 ? > > The autoregulated swappiness patch tries to get some sort of common ground, > where it sacrifices performance slightly currently to improve what happens > the next time you use your machine substantially. Because it changes with the > amount of application pages in ram, it will not increasingly sacrifice > performance when your memory is full with application pages. What it will not > do is improve the swap thrash situation when you have grossly overloaded your > ram. > > Con
My box rocks with you patch Con ! Swappiness is floating between 50->65. I never saw a 2.6 box so quick in rl5.
Thanks ! FabF
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