# 2.6.23 kernel slowdown when the system is "loaded" OR Xorg

## mrfree

I noticed my system with 2.6.23 kernel (tuxonice-2.6.23-r4) slowdown when the load increase (compiling for example) all works well using 2.6.22 series.

Any ideas on which kernel options should I try to toggle or any other clues?

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## Aszrael

Hi,

does this happen also when heavily accessing your disk?

If so you might want to check your kernel-config for

CONFIG_IOSCHED_*

CONFIG_DEFAULT_IOSCHED=

If it's only happening while compiling you can set 

PORTAGE_NICENESS=

in your /etc/make.conf as a workaround.

Aszrael

Some info on available schedulers stolen from http://www.wlug.org.nz/LinuxIoScheduler

 *Quote:*   

> 
> 
> Noop Scheduler
> 
> This scheduler only implements request merging.
> ...

 

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## diaconal

I think I have similar problem. The system seems to be less responsive as before, especially when compile in background (portage niceness was always set to 3) and switching tabs in Firefox. I jumped back to gentoo-sources-2.6.22-r8 and it "feels" like its faster but not entirely sure. The following packages were also recently updated so I'm not exactly which is the culprit:

```

=www-client/mozilla-firefox-2.0.0.11 from 2.0.0.10

=x11-drivers/xf86-video-i810-2.2.0 from 2.1.0

```

As for the scheduling, I didn't notice any difference between my kernel configs

```

CONFIG_IOSCHED_NOOP=y

# CONFIG_IOSCHED_AS is not set

# CONFIG_IOSCHED_DEADLINE is not set

CONFIG_IOSCHED_CFQ=y

```

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## mrfree

I'm using CFQ too and the kernel config was obtained using make oldconfig with the 2.6.22 .config file so the configurations are very "similar"

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## diaconal

Hey,

It turned out that xf86-i810-2.2.0 was the reason for slowdown. I downgraded to 2.1.0 and the system is back as it was before, with new kernel and firefox. See if that works for you....

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## JC99

Where in the kernel config (make menuconfig) do I find the choice for schedulers. The one I am currently using is "Anticipatory". What is the newest and latest scheduler for 2.6.23?

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## Dralnu

 *EvilEye wrote:*   

> Where in the kernel config (make menuconfig) do I find the choice for schedulers. The one I am currently using is "Anticipatory". What is the newest and latest scheduler for 2.6.23?

 

There are 4 (noop, deadline, anticipatory, and cfq), with three of them (all but noop) able to be set as default. Each is there for a diffrent job, so I suggest compiling them all in and playing with them (via echo "sched" > /sys/block/hda/queue/scheduler) to see how things respond. I personally have better performance with deadline (designed to line up writes/reads based on the amount of time needed to complete it), and the worst with cfq (gives equal time to all read/write ops, meaning there will be alot of head movement if you need alot of hdd i/o)

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## JC99

Where in menuconfig do I find these options?

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## Dralnu

 *EvilEye wrote:*   

> Where in menuconfig do I find these options?

 

Run a search for CFQ or something similar. I don't remember off the top of my head, but I think its under Device Drivers.

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## mrfree

 *diaconal wrote:*   

> It turned out that xf86-i810-2.2.0 was the reason for slowdown. I downgraded to 2.1.0 and the system is back as it was before, with new kernel and firefox. See if that works for you....

  You're probably right but I don't know if the "problem" is directly related with the xf86-i810 driver it could be related with EXA: 2.2.0 uses EXA by default, 2.1.0 uses XAA and I found a lot of posts on google about "intel exa slow"  :Smile: 

I tried both 2.1.0 (stable) and 2.2.0 using XAA but the problem doesn't disappear, the system works well but it monstrously slowdown when the load increase (compiling for example)

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## Dralnu

 *mrfree wrote:*   

>  *diaconal wrote:*   It turned out that xf86-i810-2.2.0 was the reason for slowdown. I downgraded to 2.1.0 and the system is back as it was before, with new kernel and firefox. See if that works for you....  You're probably right but I don't know if the "problem" is directly related with the xf86-i810 driver it could be related with EXA: 2.2.0 uses EXA by default, 2.1.0 uses XAA and I found a lot of posts on google about "intel exa slow" 
> 
> I tried both 2.1.0 (stable) and 2.2.0 using XAA but the problem doesn't disappear, the system works well but it monstrously slowdown when the load increase (compiling for example)

 

So the diffrence between 2.2.0 and 2.1.1 doesn't seem to exist until you reach a load?

I've downgraded to 2.1.1 for now, and it seems to have solved the problem. If anyone has any ideas on the improvements of 2.2.0, or a reason to use it without reaching a massive slowdown, please tell.

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## mrfree

 *Dralnu wrote:*   

> So the diffrence between 2.2.0 and 2.1.1 doesn't seem to exist until you reach a load?

 Exactly and with 1.7.4 too

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## mrfree

Now using 2.1.1 (with XAA) the system seems to work well, but in the meanwhile I downgraded x11-drm to 20070314 because the 20071019 disable intel dri (see the bugzilla) update the kernel to tuxonice-sources-2.6.23-r5 so I'm not sure the solution is strictly related with the driver   :Razz: 

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## Dralnu

 *mrfree wrote:*   

> Now using 2.1.1 (with XAA) the system seems to work well, but in the meanwhile I downgraded x11-drm to 20070314 because the 20071019 disable intel dri (see the bugzilla) update the kernel to tuxonice-sources-2.6.23-r5 so I'm not sure the solution is strictly related with the driver  

 

I'm going to downgrade that myself. I have been wondering why it kept saying my system wasn't able to run dri...

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## sargek

I am having exactly the same issue with slowness under load and kernel 2.6.23, but am running an Nvidia driver. I have switched between agpgart and the nvagp and that didn't matter, looked at 

```
free -m
```

 also and my system is doing fine with buffers and ram - no excessive usage. I've checked to see if DMA is enabled for disks and it is. I am going to try the scheduler switch to cfq to see if that helps. The system is fine until I start emerging then it falls on it's face. I know something is wrong when Debian Testing was faster...  :Shocked: 

Will also try portage niceness as well. Thanks for the tips.

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## pappy_mcfae

I found this thread, and it seems to echo what y'all have been observing. I am just now compiling a .23 version kernel to see if I get the same laggy console with it as I got with .24 kernels. I'll report back once that's done.

Blessed be!

Pappy

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