Re: [gentoo-performance] Horrible performance

[Kacper Kopczyński]

Dnia 2010-08-25, o godz. 03:32:40
Alex Schuster <wonko@×××××××××.org> napisał(a):

> Me again.
>
> I wrote here about my problems with mplayer stuttering during
> emerges. Then I wrote that the problem went away when I installed
> Gentoo again, moving from i686 to x86_64. But the problems are back,
> and worse than ever. This is driving me crazy. CRAZY!
>
> I have an AMD Athlon(tm) Dual Core Processor 4850e CPU, on-board
> Radeon HD 3200 graphics, 4GB of memory, an 1.5 TB drive. Lots of LVM
> volumes, all encrypted, except for /usr/src and portage stuff. The
> system is ~amd64, and I have -march=k8-sse3 in my CFLAGS. Current
> kernel is 2.6.34-tuxonice, but I also tried others. I'm running KDE4
> with desktop effects enabled, X itself takes about 30-40% of CPU time
> according to top. After system startup and login into KDE, 3.5G of
> RAM are occupied. This increases after a while, and I need swap
> space. Nothing to worry about I think.
>
> Performance does not feel too bad at first. But after a while, I
> cannot even play videos during emerges. The playback stutters,
> sometimes I have pauses for several seconds. As long as there is no
> swap space occpied, it's not so bad I think. Maybe I have a probelm
> with disk I/O, and things get much worse when swapping occurs. When I
> look at iotop, I see various programs like chromium and various KDE
> applications appear. I guess that's normal, but should not be
> noticeable. Hey, there were times when I created a 2G tmpfs
> for /var/tmp/portage, with only 3G on my 32bit system. BTW, I lowered
> my swappiness to 10. This helps a little I think, because the
> swapping occurs later, the system is more responsive.
>
> And it feels like things get worse and worse, it's not like there was
> a specific point when I thought it's slow again. Like there were some
> degragation going on - fragmentation, bitrot, I don't know. It's just
> how it feels to me.
>
> I am debugging this for some days now. I tried different kernels,
> from 2.6.29 to 2.6.35, including the kernel I had running after the
> switch to 64bit, when I thought all was fine. No change. But all
> kernels were configured nearly identical, so I booted a GRML live-cd
> and used this kernel .config as a template. Does not feel better.
>
> When I thought the problem was gone, I had installed the system on my
> 2nd 1.5 TB drive. Meanwhile I copied the partitions back to the 1st
> drive, so I suspected a difference in the drives. I use the 2nd drive
> for backups (using rdiff-backup), with similar partitions, so I only
> have to exchange the LVM volume group names of the two drives in
> order to run my system from the 2nd one. I tried this, but it did not
> help.
>
> And I have similar problems when copying data between some old PATA
> drives. When I copy stuff and do a mkfs on another partition, mplayer
> sometimes stutters and hangs for ten seconds. No joy. Working with
> KDE sucks, switching dektops sometimes takes ages, and even now I am
> typing faster than kmail can display the characters. That's with am
> emerge of chromium running, with PORTAGE_NICENESS=10 and using ionice
> -c 3. Load is around 8, but sometimes gets even higher. And then,
> load suddenly drops back to lower values, as if somthing was
> blocking. Some applications swapping, maybe.
>
> Now I am out of ideas. I really hope someone here has one. I cannot
> work with this system any more when emerges are going on.
>
> I put my kernel config, make.conf, dmesg and such stuff to
> http://www.wonkology.org/gentoo/ in case someone wants to have a look
> at it. Any help is GREATLY appreciated.
>
> 	Wonko
>

Checkout configuration of your video driver - X should not take more
than 5% of cpu when iddle (with some minor effects). Perhaps kde is not
using OpenGL? Do you have OpenGL enabled?

Amount of ram you have should be sufficent to compile everything
without access to swap space.

-- 
Kacper Kopczyński