High cpu-usage on copy files

Vrenn · Guru Joined: 15 Dec 2004 Posts: 318

Dear Gentoo experts!

I solved many problems with my Asus ROG 751JY (Haswell). But some remain.
I noticed copy a file from one drive to another (no matter if they are ssd, hdd or usb) my kde4.14.8 has high cpu-usage on one core.

Ubuntu (Unity), Fedora23 (gnome) and arch (desktopless) have low cpu-usage on copy files.
Kubuntu 15.10 had high cpu-usage too!

Is this a kde-problem or do I have some missing kernel opt?
What is your cpu in KDE on copy files?
Do AHCI PCIe or SATA drives need extra dma-engine drivers?

Thanks for your help!
_________________
With nice greetings
Vrenn

NeddySeagoon · Posted: Tue Dec 22, 2015 1:30 pm Post subject:

Vrenn,

You can test if its KDE or or not by doing a copy from a shell, not a shell window in KDE.

High CPU use on copy usually indicates that PIO mode is in use, rather than DMA mode.
PIO - Programmed Input/Output requires that the CPU read and write every byte.

DMA - Direct Memory Access, only needs the CPU to set up the direction, the buffer location, buffer size and tell the DMA controller to go.
That's just a few bytes.

USB versions below 3.0 only support PIO.
USB 3.0 and SATA should all use DMA.
PATA can use either.
SATA running in PATA compatibility mode usually uses PIO.

Please post the output of lspci, which may offer some hints.
Also put your dmesg onto a pastebin, there will be more detail there.

-- edit --

You are posting about several problems. Please only work on one at a time or both you and your helpers will get confused.
Your helpers may not have visibility of changes made to your system due to you working other issues.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Vrenn · Guru Joined: 15 Dec 2004 Posts: 318

Thank you for your quick answer.
I'm sorry that posting multiple problems is bad, I'll go slow, (just one as you say) next time. But please understand me, that I use gentoo since 2003 and this machine makes me despair.
I thought splitting problems up is better, but these two might have to do something with each other so the solution for one could be somehow a solution for the other.

I especially mean problem "Samsung SSD producing host bus errors" https://forums.gentoo.org/viewtopic-t-1035738.html
But the upper one just hits kernel 3.18.22+. The high-cpu-copy-problem also appears in my current gentoo kernel 3.14.58.

To your questions:

NeddySeagoon · Posted: Tue Dec 22, 2015 5:28 pm Post subject:

Vrenn,

Vrenn · Guru Joined: 15 Dec 2004 Posts: 318

Thanks for giving me certainty in the AHCI-mode, your opinion is important for me.
I have looked in UEFI, Asus did deliver the notebook in AHCI-mode.

I want to upgrade the kernel, you are right. But another problem I have is that all kernels (gentoo&vanilla) above 3.18.21 producing host bus errors on my samsung ssd
Now it seems for me that this might be my key-problem. So I'm stuck with 3.14 hoping it is maintained in the stable tree for some time.

The enp60s0 thing is a normal behaviour in my case I believe:
I use networkmanager getting its IP by dhcp. As I need to run server-demons sometimes on my laptop, it gets a "fixed dhcp address" from my router (AVM Fritzbox).
Now, when I reboot my laptop in a short time (e.g. testing another kernel) my router refuses to give out the mac-fixed-address a second time and looks some time if it is really free. So networkmanager doesn't get an IP-config in the first place, but is served after the two minutes.
This doesn't happen in normal laptop usage.

edit: And I might forgot to tell, that I disabled kdm/X in systemd for the copy-test in the real shell. I started both after the test so nvidia can be late in dmesg. Sorry about that.
_________________
With nice greetings
Vrenn