# System lags *heavily* during cp.

## Martux

Hello.

Here's another problem which annoys me right now.

I copy over several gigs from one external SATA-drive to my internal SATA drive.

Even if it copies quite fast, the system is unresponsive beyond usage during cp.

Meaning, music stops, typing is very laggy, swiching windows takes seconds.

I just reactivated my swap space of 2 GB, though this machine has 4 GB of RAM of which gkrellm tells me 430MB are used. That brought some relief, right now 55MB swap are used (and only 430MB RAM   :Twisted Evil: ).

What really makes me angry is, that this is a Intel Quad Core Q9450 with 4G RAM. The harddisk are quite recent SATA-drives from Samsung with 32MB cache. This must work better...

Where could i look for solutions?

Ah, in kernel i have activated libata and AHCI and nothing else.

Thanks, 

Marcus

EDIT: The above mentioned is true even if the cp process is reniced to 19...

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## DaggyStyle

what system is that 32 bit or 64 bit?

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## Martux

64bit, ~amd64

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## albright

There4 is a giant thread on what looks to be your problem:

https://forums.gentoo.org/viewtopic-t-482731-highlight-disk.html

It's a bad problem, with no hint of a solution so far as I can tell. It has been

like this for years!!

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## DaggyStyle

 *albright wrote:*   

> There4 is a giant thread on what looks to be your problem:
> 
> https://forums.gentoo.org/viewtopic-t-482731-highlight-disk.html
> 
> It's a bad problem, with no hint of a solution so far as I can tell. It has been
> ...

 

bingo... you beat me to the punch.

welcome to the club.

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## Martux

 *Quote:*   

> 
> 
> https://forums.gentoo.org/viewtopic-t-482731-highlight-disk.html
> 
> 

 

Holy shit... I really have exactly the same problem as the thread starter   :Sad: 

This thread is two years old and over 30 pages long, this can't be true.

Can anybody sum up this for me? I only read the first 2 and the last 2 pages.

Seems this is kernel related and not fixed at all?!

Regards, Martux

PS: It's not that I have these problems during compile, it's just when e.g. replaying my backup.

Still annoying on such a fast computer...

EDIT: I am blind, i just "recovered" the Gentoo on AMD64 subforum   :Embarassed:   :Embarassed: 

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## DaggyStyle

in a nuteshell, something in the kernel is not working good in relation to io usage no one of the kernel dev (AFAIK) tries to fix it...

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## Martux

Thanks for the quick overview.

That's really a nasty bugger...

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## Mad Merlin

There's also kernel bugs open for this:

http://bugzilla.kernel.org/show_bug.cgi?id=7372

http://bugzilla.kernel.org/show_bug.cgi?id=12309

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## saellaven

There's a massive thread with sub-threads on lkml right now concerning the increasing latencies people have been experiencing over the last couple years. Linus has started banging some heads around about how bad it's gotten and there are some patches trickling out, threats to switch the default disk IO scheduler from CFQ to the Anticipatory Scheduler if CFQ isn't fixed ASAP, creating a process to auto-tune throughput vs latency in the kernel, etc. Virtually all of the big names in kernel development are involved first hand, so I'm guessing we'll see something within the next week, most likely for 2.6.30. Whether or not it gets included for 2.6.29.x will probably come down to how invasive the fix is.

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