Gentoo Archives: gentoo-performance

From: "J. Roeleveld" <joost@××××××××.org>
To: gentoo-performance@l.g.o
Subject: Re: [gentoo-performance] Horrible performance
Date: Wed, 25 Aug 2010 08:04:30
In Reply to: [gentoo-performance] Horrible performance by Alex Schuster
Hi Alex,

On Wednesday 25 August 2010 03:32:40 Alex Schuster wrote:
> Me again. > > 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.
Encrypted filesystems can cause additional with activity, but I would expect that to remain the same over a long period. However, how is the write and read performance on those disks? You're running KDE4, guess you went for the default and use mysql for "app- office/akonadi-server". I switched to using "sqlite" for this due to issues getting it to work with mysql. I think this might help there?
> 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.
Do you also encrypt swap? Disk I/O is, in my experience, a very common cause for "freeze-ups". Can you test with unencrypted disks to see if the issue occurs then as well?
> 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.
Very possibly, maybe an idea to check which applications are hogging the memory. If it is the swapping of the system, then this will be caused by the most memory-hungry processes. Can you post the result of: "ps axu"? This will give an indication which processes are running and using a lot of memory.
> 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.
Had similar issues with a desktop machine myself, managed to kill some "features" that I wasn't using and this solved most of the problems.
> I put my kernel config, make.conf, dmesg and such stuff to > in case someone wants to have a look at > it. Any help is GREATLY appreciated.
Lets see where checking for IO-speeds and memory-usage of your apps take us :) -- Joost


Subject Author
Re: [gentoo-performance] Horrible performance Alex Schuster <wonko@×××××××××.org>
Re: [gentoo-performance] Horrible performance Alex Schuster <wonko@×××××××××.org>