Messages in this thread | | | Date | Tue, 03 Feb 2004 18:13:06 +1100 | From | Nick Piggin <> | Subject | Re: 2.6.1 slower than 2.4, smp/scsi/sw-raid/reiserfs |
| |
Samium Gromoff wrote:
>>>The machine is a dual P3 450MHz, 512MB, aic7xxx, 2 disk RAID-0 and >>> ReiserFS. It's a few years old and has always run Linux, most >>> recently 2.4.24. I decided to try 2.6.1 and the performance is >>> disappointing. >>> >> >>2.6 has a few performance problems under heavy pageout at present. Nick >>Piggin has some patches which largely fix it up. >> > >I`m sorry, but this is misguiding. 2.6 does not have a few performance >problems under heavy pageout. > >It`s more like _systematical_ _performance_ _degradation_ increasing with >the pageout rate. The more the box pages out the more 2.6 lags behind 2.4. > >
Well it is a few problems that cause significant performance regressions. But nevermind semantics...
>What i`m trying to say is that even light paging is affected. And light >paging is warranted when you run, say, KDE on 128M ram. > >Go measure the X desktop startup time on a 48M/64M boxen--even light paging >causes 2.6 to be just sloower. Also the vm thrashing point is much much earlier. > >
Have a look here: http://www.kerneltrap.org/~npiggin/vm/3/ and here: http://www.kerneltrap.org/~npiggin/vm/4/ patches here: http://www.kerneltrap.org/~npiggin/vm/
and I have a couple of things which improve results even more. True, its only kbuild, but after I do a bit more tuning I'll focus on other things - I'm hoping most of the improvements carry over to other cases though.
Tentatively, it looks like 2.6 under very heavy swapping can actually be significantly improved over 2.4.
>Ask Roger Luethi for details. > >
Andrew is quite well versed in the details :)
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |